August 2013 - Utah-Astronomy - mailman.xmission.com

Re: [Utah-astronomy] Galaxy NGC 6946 through smoke and meteriors
by Joe Bauman 18 Aug '13

18 Aug '13

Dear all -- I never interpreted any of your responses as an attack! I love lively debates and I am always grateful to lose false assumptions. Thank you for a stimulating and very educational discussion. -- Joe ------------------------------ On Sat, Aug 17, 2013 10:56 PM MDT Brent Watson wrote: >Joe, > >All objects in the sky remain fixed in relation to the celestial sphere. They do not rotate from one part of the sky to another - they are fixed. That relationship does not change in relation to the celestial sphere. If one spiral arm points to the north celestial pole, or any other place on the celestial sphere, it will always point to that location. The same is true of one object in relation to another. It WILL NOT rotate. If you draw a great circle from one object to another you will see that the great circle does not move against the celestial sphere. > >Now, specifically, the Perseid radiant, and NGC 6946 have a FIXED relationship with each other. The galaxy does not rotate against the celestial sphere. The path of a meteor against the celestial sphere is along a great circle. They cannot travel along a different path. If you do not believe this, please study your spherical trigonometry and physics. It can be no other way. Therefore, if you have two tracks across the galaxy, and they are not parallel nor coincident, they have to have different radiants. If they have different radiants then at least one of them is not a Perseid. It is simple geometry. Time has nothing to do with it. It is irrelevant because we are talking about objects on the celestial sphere. > >What you are suggesting goes against all physics and geometry. At most, one of the traces in your images is a Perseid, and I question whether they are meteors at all. > >Sorry to disagree, but "I cannot change the laws of physics" - nor geometry. Please do not interpret this as an attack against you personally. I am only questioning the assumption that you captured two Perseid meteors. I still like your images and find genuine interest in the color shift caused by the smoke. That is intriguing to me. > >Brent > > >________________________________ > From: Joe Bauman <josephmbauman(a)yahoo.com> >To: utah-astronomy(a)mailman.xmission.com >Sent: Saturday, August 17, 2013 2:00 PM >Subject: Re: [Utah-astronomy] Galaxy NGC 6946 through smoke and meteriors > > > > >I wasn't claiming a Perseus could come from the North Star. I used that as a thought experiment to show that a meteor coming from a certain location will cross different constellations depending on when it happens because of the sky's rotaion. It works the same way with another meteor locus and a half-hour difference, just not as much of a difference. Celestial targets do rotate as you track them with a telescope but your tracking compensates for this. If you weren't automatically compensating you would need to use a clumsy device called a field derotator. Look up to see how it works. Just as the moon rotates from one pole up to the opposite pole up during the night, a galaxy does too. Pretend a galaxy is adjacent to the moon and you can see them both. Does the moon "stand on its head" while the galaxy doesn't? Now say the galaxy is in some other location and we're talking about half an hour. Do you imagine it has no rotational change in that period? If >a meteor is coming through it a dust stream at 3:14 a.m. and another at 3:44, would the galaxy have rotated relative to the meteor source in that time? I think so bur I don't claim to know anything about celestial mechanics. -- Joe > > >------------------------------ >On Sat, Aug 17, 2013 12:50 PM MDT Siegfried Jachmann wrote: > >>I think Brent is spot on. >> >> >>On Sat, Aug 17, 2013 at 10:15 AM, Chuck Hards <chuck.hards(a)gmail.com> wrote: >> >> Brent, I think Joe is just having trouble with polar coordinates. >> Joe, a straight line on the sky will always project as a curve on a >> 2-dimensional computer screen, unless extremely short. >> On Aug 17, 2013 9:23 AM, "Brent Watson" <brentjwatson(a)yahoo.com> wrote: >> >> > Joe, >> > >> > I think we have to agree to disagree. A perseid can never come from the >> > North Star. Likewise, north in your photo will always be north, and the >> > direction the galaxy is facing relative to celestial north will not >> change. >> > Your exercise of putting a piece of paper on your screen is not valid >> > either. I am at a loss to be able to explain this unless we sit down >> > together and use some visual aids, so lets agree to disagree. >> > >> > Brent >> > >> > >> > ________________________________ >> > From: Joe Bauman <josephmbauman(a)yahoo.com> >> > To: Utah Astronomy <utah-astronomy(a)mailman.xmission.com> >> > Sent: Friday, August 16, 2013 11:38 PM >> > Subject: Re: [Utah-astronomy] Galaxy NGC 6946 through smoke and meteriors >> > >> > >> > That's just not entirely true, Brent. The galaxy itself appears to rotate >> > as the night progresses, even minute by minute, just as the moon ends >> > upside down at sunrise from what it was at sunset. Let's remember first >> > that the Perseids aren't really coming from Perseus but from a stream of >> > dust through which Earth passes. The dust doesn't rotate as Earth does. >> > Then do this thought experiment: pretend you're a meteor that's going to >> > flash into our atmosphere from the direction of the North Star and cross >> > the whole sky. If you do that in the middle of the night you cross a >> > certain number of constellations that are up at that time. But if you >> > decide to zoom in 12 hours later, during the day, you will cross an >> > entirely different set of (unseen to Earthlings) constellations. The >> entry >> > point was the same place and the angle of entry was the same but the >> > trajectory crossed entirely different locations. If you vary that by an >> > hour instead of half a day you still >> > get a different track. A galaxy rotates as it crosses the sky just the >> way >> > the moon does. I got my planetarium program going and I put the edge of a >> > piece of paper from NGC6946 to Perseus. Then I advanced the time by half >> an >> > hour. The galaxy rotated considerably in that time while I kept the paper >> > pointed at Perseus. In half an hour the direction that the Perseid >> meteors >> > streak across the galaxy changes. -- Joe >> > >> > >> > >> > ________________________________ >> > From: Brent Watson <brentjwatson(a)yahoo.com> >> > To: Utah Astronomy <utah-astronomy(a)mailman.xmission.com> >> > Sent: Friday, August 16, 2013 9:31 PM >> > Subject: Re: [Utah-astronomy] Galaxy NGC 6946 through smoke and meteriors >> > >> > >> > Joe, >> > >> > The whole sky rotates at the same rate. It rotates very close to 1 hour >> > of right ascension per hour of mean solar time, as measured by your >> watch. >> > The angle between the radiant and the galaxy will not change, neglecting >> > the movement of the radiant itself. (That movement happens over days, >> not >> > minutes.) Both of those traces cannot be due to Perseid meteors because >> of >> > the angle formed by the two traces. One of them MAY be, but the other is >> > certainly not. How does the the line from the radiant intersect NGC 6946 >> > as seen on your digital planetarium? Does it pass through at the same >> > angle as one of the traces? If not, then both are either sporadic or not >> > meteors at all. >> > >> > Brent >> > >> > >> > ________________________________ >> > From: Joe Bauman <josephmbauman(a)yahoo.com> >> > To: Utah Astronomy <utah-astronomy(a)mailman.xmission.com> >> > Sent: Friday, August 16, 2013 6:09 PM >> > Subject: Re: [Utah-astronomy] Galaxy NGC 6946 through smoke and meteriors >> > >> > >> > Looking at my computerized planetarium, it's certainly possible to draw a >> > radiant from Perseus to NGC 6946 at the time I took the views, about 3:14 >> > and 3:44 a.m., respectively, on Wednesday morning. I haven't had time to >> > figure it out formally yet, but by running my planetarium program from >> the >> > first to the second time it looks like NGC 6946 revolves about the same >> > amount as the difference in the lines in the two subs. Because they are >> in >> > different sections of the sky, the galaxy and the constellation revolve >> at >> > different rates. So unless someone wants to be a lot more scientific >> about >> > calculating >> > these things and proves me wrong, I will continue to believe they are >> both >> > Perseids. -- Joe >> > >> > >> > >> > >> > ________________________________ >> > From: Chuck Hards <chuck.hards(a)gmail.com> >> > To: Utah Astronomy <utah-astronomy(a)mailman.xmission.com> >> > Sent: Friday, August 16, 2013 4:40 PM >> > Subject: Re: [Utah-astronomy] Galaxy NGC 6946 through smoke and meteriors >> > >> > >> > For the meteors to be considered Perseids, they must have radiated from >> the >> > Perseid radiant. They can appear anywhere in the sky, and at any angle >> > relative to the observer, but in order to be a member of a given shower, >> if >> > you extend their path backwards across the sky, it must intersect the >> > radiant. If it doesn't, it's a sporadic, or a member of a different >> > shower. Some showers do overlap their times of activity. >> > >> > All members of a given shower hit the earth's atmosphere at the same >> > angle. They are traveling parallel in space. It just looks different >> to a >> > ground-based observer. >> > >> > Imagine the radiant as a sort of "vanishing point" in the sky. >> > >> > On Fri, Aug 16, 2013 at 2:25 PM, Joe Bauman <josephmbauman(a)yahoo.com> >> > wrote: >> > >> > > >> > > >> > > >> > > I did consult a star atlas ant I think they could be perseids -- >> > > meteorites seem to show up at various parts of the sky, not necessarily >> > > heading from Perseus directly. It is a wide stream of cometary dust >> that >> > > yge Earth passes through and I reckon that the atmosphere may hit the >> > dust >> > > grains at various angles. Also saying the tracks look too uniform >> isn't a >> > > good way to judge them when you consider the field of view is tiny -- >> in >> > a >> > > larger field they may have been less regular over s lmgrt stretch of >> > their >> > > entry path. Well, that's my story and I'm stickin' with if! -- Thanks, >> > Joe >> > > >> > > ------------------------------ >> > > On Fri, Aug 16, 2013 9:48 AM MDT Brent Watson wrote: >> > > >> > > >Joe, >> > > > >> > > >They can't both be Perseids. They are coming from different >> directions. >> > > I am not sure where the Perseid radiant is with respect to your >> > > photograph, but in fact neither may be a Perseid. Please check the >> > > direction of travel. The tracks also look pretty uniform. In fact, >> > almost >> > > too uniform to be meteors. Are they instead, satellites? >> > > > >> > > >> > _______________________________________________ >> > Utah-Astronomy mailing list >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > >> > Send messages to the list to >> > Utah-Astronomy(a)mailman.xmission.com >> > >> > The Utah-Astronomy mailing list is not affiliated with any astronomy >> club. >> > >> > To unsubscribe go to: >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > Then enter your email address in the space provided and click on >> > "Unsubscribe or edit options". >> > _______________________________________________ >> > Utah-Astronomy mailing list >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > >> > Send messages to the list to >> > Utah-Astronomy(a)mailman.xmission.com >> > >> > The Utah-Astronomy mailing list is not affiliated with any astronomy >> club. >> > >> > To unsubscribe go to: >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > Then enter your email address in the space provided and click on >> > "Unsubscribe or edit options". >> > _______________________________________________ >> > Utah-Astronomy mailing list >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > >> > Send messages to the list to >> > Utah-Astronomy(a)mailman.xmission.com >> > >> > The Utah-Astronomy mailing list is not affiliated with any astronomy >> club. >> > >> > To unsubscribe go to: >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > Then enter your email address in the space provided and click on >> > "Unsubscribe or edit options". >> > _______________________________________________ >> > Utah-Astronomy mailing list >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > >> > Send messages to the list to >> > Utah-Astronomy(a)mailman.xmission.com >> > >> > The Utah-Astronomy mailing list is not affiliated with any astronomy >> club. >> > >> > To unsubscribe go to: >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > Then enter your email address in the space provided and click on >> > "Unsubscribe or edit options". >> > _______________________________________________ >> > Utah-Astronomy mailing list >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > >> > Send messages to the list to >> > Utah-Astronomy(a)mailman.xmission.com >> > >> > The Utah-Astronomy mailing list is not affiliated with any astronomy >> club. >> > >> > To unsubscribe go to: >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > Then enter your email address in the space provided and click on >> > "Unsubscribe or edit options". >> > >> _______________________________________________ >> Utah-Astronomy mailing list >> http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> >> Send messages to the list to >> Utah-Astronomy(a)mailman.xmission.com >> >> The Utah-Astronomy mailing list is not affiliated with any astronomy club. >> >> To unsubscribe go to: >> http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> Then enter your email address in the space provided and click on >> "Unsubscribe or edit options". >> >> >> >> >>-- >>Siegfried >>_______________________________________________ >>Utah-Astronomy mailing list >>http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> >>Send messages to the list to >>Utah-Astronomy(a)mailman.xmission.com >> >>The Utah-Astronomy mailing list is not affiliated with any astronomy club. >> >>To unsubscribe go to: >>http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>Then enter your email address in the space provided and click on "Unsubscribe or edit options". > > >_______________________________________________ >Utah-Astronomy mailing list >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy > >Send messages to the list to >Utah-Astronomy(a)mailman.xmission.com > >The Utah-Astronomy mailing list is not affiliated with any astronomy club. > >To unsubscribe go to: >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >Then enter your email address in the space provided and click on "Unsubscribe or edit options". >_______________________________________________ >Utah-Astronomy mailing list >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy > >Send messages to the list to >Utah-Astronomy(a)mailman.xmission.com > >The Utah-Astronomy mailing list is not affiliated with any astronomy club. > >To unsubscribe go to: >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >Then enter your email address in the space provided and click on "Unsubscribe or edit options".

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Re: [Utah-astronomy] WHITE FLAG -- was Galaxy NGC 6946 through smoke and meteriors
by Joe Bauman 18 Aug '13

18 Aug '13

Chuck, the first was taken at 3:14 a.m. and the second at 3:44. Thanks for the interest, Joe ------------------------------ On Sun, Aug 18, 2013 5:40 AM MDT Chuck Hards wrote: >Joe's first pic, the brighter trail of the two, has that meteor "feel" to >it- it's not solidly consistent throughout it's length, and the knots >aren't regular which could denote satellite rotation; while the dimmer one >seems more like a satellite or small piece of space junk. > > Knowing the time of night of the exposures could help nail it down. >Satellites shine by reflected sunlight so are typically seen shortly after >sunset and before sunrise. Only those in very high orbits are visible in >the middle of the night, and those don't tend to move very fast. >Geosynchronous satellites at most just bob around a bit relative to the >background stars, but not over very short lengths of time. > >If we knew when the pics were taken, it would be easy to compare them to >online databases of known satellites and larger space junk. Of course >there are hundreds of thousands of smaller bits of orbiting flotsam and >jetsam that aren't catalogued. > >My gut is telling me that Joe got at least one meteor and possibly two >depending on time of night; some careful sleuthing may prove me wrong. > > >On Sat, Aug 17, 2013 at 7:48 PM, Jared Smith <jared(a)smithplanet.com> wrote: > >> For what it's >> worth, I think it most likely that they are satellites, but we'll >> never know for sure. >> >> >_______________________________________________ >Utah-Astronomy mailing list >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy > >Send messages to the list to >Utah-Astronomy(a)mailman.xmission.com > >The Utah-Astronomy mailing list is not affiliated with any astronomy club. > >To unsubscribe go to: >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >Then enter your email address in the space provided and click on "Unsubscribe or edit options".

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Re: [Utah-astronomy] Galaxy NGC 6946 through smoke and meteriors
by Joe Bauman 17 Aug '13

17 Aug '13

I wasn't claiming a Perseus could come from the North Star. I used that as a thought experiment to show that a meteor coming from a certain location will cross different constellations depending on when it happens because of the sky's rotaion. It works the same way with another meteor locus and a half-hour difference, just not as much of a difference. Celestial targets do rotate as you track them with a telescope but your tracking compensates for this. If you weren't automatically compensating you would need to use a clumsy device called a field derotator. Look up to see how it works. Just as the moon rotates from one pole up to the opposite pole up during the night, a galaxy does too. Pretend a galaxy is adjacent to the moon and you can see them both. Does the moon "stand on its head" while the galaxy doesn't? Now say the galaxy is in some other location and we're talking about half an hour. Do you imagine it has no rotational change in that period? If a meteor is coming through it a dust stream at 3:14 a.m. and another at 3:44, would the galaxy have rotated relative to the meteor source in that time? I think so bur I don't claim to know anything about celestial mechanics. -- Joe ------------------------------ On Sat, Aug 17, 2013 12:50 PM MDT Siegfried Jachmann wrote: >I think Brent is spot on. > > >On Sat, Aug 17, 2013 at 10:15 AM, Chuck Hards <chuck.hards(a)gmail.com> wrote: > >> Brent, I think Joe is just having trouble with polar coordinates. >> Joe, a straight line on the sky will always project as a curve on a >> 2-dimensional computer screen, unless extremely short. >> On Aug 17, 2013 9:23 AM, "Brent Watson" <brentjwatson(a)yahoo.com> wrote: >> >> > Joe, >> > >> > I think we have to agree to disagree. A perseid can never come from the >> > North Star. Likewise, north in your photo will always be north, and the >> > direction the galaxy is facing relative to celestial north will not >> change. >> > Your exercise of putting a piece of paper on your screen is not valid >> > either. I am at a loss to be able to explain this unless we sit down >> > together and use some visual aids, so lets agree to disagree. >> > >> > Brent >> > >> > >> > ________________________________ >> > From: Joe Bauman <josephmbauman(a)yahoo.com> >> > To: Utah Astronomy <utah-astronomy(a)mailman.xmission.com> >> > Sent: Friday, August 16, 2013 11:38 PM >> > Subject: Re: [Utah-astronomy] Galaxy NGC 6946 through smoke and meteriors >> > >> > >> > That's just not entirely true, Brent. The galaxy itself appears to rotate >> > as the night progresses, even minute by minute, just as the moon ends >> > upside down at sunrise from what it was at sunset. Let's remember first >> > that the Perseids aren't really coming from Perseus but from a stream of >> > dust through which Earth passes. The dust doesn't rotate as Earth does. >> > Then do this thought experiment: pretend you're a meteor that's going to >> > flash into our atmosphere from the direction of the North Star and cross >> > the whole sky. If you do that in the middle of the night you cross a >> > certain number of constellations that are up at that time. But if you >> > decide to zoom in 12 hours later, during the day, you will cross an >> > entirely different set of (unseen to Earthlings) constellations. The >> entry >> > point was the same place and the angle of entry was the same but the >> > trajectory crossed entirely different locations. If you vary that by an >> > hour instead of half a day you still >> > get a different track. A galaxy rotates as it crosses the sky just the >> way >> > the moon does. I got my planetarium program going and I put the edge of a >> > piece of paper from NGC6946 to Perseus. Then I advanced the time by half >> an >> > hour. The galaxy rotated considerably in that time while I kept the paper >> > pointed at Perseus. In half an hour the direction that the Perseid >> meteors >> > streak across the galaxy changes. -- Joe >> > >> > >> > >> > ________________________________ >> > From: Brent Watson <brentjwatson(a)yahoo.com> >> > To: Utah Astronomy <utah-astronomy(a)mailman.xmission.com> >> > Sent: Friday, August 16, 2013 9:31 PM >> > Subject: Re: [Utah-astronomy] Galaxy NGC 6946 through smoke and meteriors >> > >> > >> > Joe, >> > >> > The whole sky rotates at the same rate. It rotates very close to 1 hour >> > of right ascension per hour of mean solar time, as measured by your >> watch. >> > The angle between the radiant and the galaxy will not change, neglecting >> > the movement of the radiant itself. (That movement happens over days, >> not >> > minutes.) Both of those traces cannot be due to Perseid meteors because >> of >> > the angle formed by the two traces. One of them MAY be, but the other is >> > certainly not. How does the the line from the radiant intersect NGC 6946 >> > as seen on your digital planetarium? Does it pass through at the same >> > angle as one of the traces? If not, then both are either sporadic or not >> > meteors at all. >> > >> > Brent >> > >> > >> > ________________________________ >> > From: Joe Bauman <josephmbauman(a)yahoo.com> >> > To: Utah Astronomy <utah-astronomy(a)mailman.xmission.com> >> > Sent: Friday, August 16, 2013 6:09 PM >> > Subject: Re: [Utah-astronomy] Galaxy NGC 6946 through smoke and meteriors >> > >> > >> > Looking at my computerized planetarium, it's certainly possible to draw a >> > radiant from Perseus to NGC 6946 at the time I took the views, about 3:14 >> > and 3:44 a.m., respectively, on Wednesday morning. I haven't had time to >> > figure it out formally yet, but by running my planetarium program from >> the >> > first to the second time it looks like NGC 6946 revolves about the same >> > amount as the difference in the lines in the two subs. Because they are >> in >> > different sections of the sky, the galaxy and the constellation revolve >> at >> > different rates. So unless someone wants to be a lot more scientific >> about >> > calculating >> > these things and proves me wrong, I will continue to believe they are >> both >> > Perseids. -- Joe >> > >> > >> > >> > >> > ________________________________ >> > From: Chuck Hards <chuck.hards(a)gmail.com> >> > To: Utah Astronomy <utah-astronomy(a)mailman.xmission.com> >> > Sent: Friday, August 16, 2013 4:40 PM >> > Subject: Re: [Utah-astronomy] Galaxy NGC 6946 through smoke and meteriors >> > >> > >> > For the meteors to be considered Perseids, they must have radiated from >> the >> > Perseid radiant. They can appear anywhere in the sky, and at any angle >> > relative to the observer, but in order to be a member of a given shower, >> if >> > you extend their path backwards across the sky, it must intersect the >> > radiant. If it doesn't, it's a sporadic, or a member of a different >> > shower. Some showers do overlap their times of activity. >> > >> > All members of a given shower hit the earth's atmosphere at the same >> > angle. They are traveling parallel in space. It just looks different >> to a >> > ground-based observer. >> > >> > Imagine the radiant as a sort of "vanishing point" in the sky. >> > >> > On Fri, Aug 16, 2013 at 2:25 PM, Joe Bauman <josephmbauman(a)yahoo.com> >> > wrote: >> > >> > > >> > > >> > > >> > > I did consult a star atlas ant I think they could be perseids -- >> > > meteorites seem to show up at various parts of the sky, not necessarily >> > > heading from Perseus directly. It is a wide stream of cometary dust >> that >> > > yge Earth passes through and I reckon that the atmosphere may hit the >> > dust >> > > grains at various angles. Also saying the tracks look too uniform >> isn't a >> > > good way to judge them when you consider the field of view is tiny -- >> in >> > a >> > > larger field they may have been less regular over s lmgrt stretch of >> > their >> > > entry path. Well, that's my story and I'm stickin' with if! -- Thanks, >> > Joe >> > > >> > > ------------------------------ >> > > On Fri, Aug 16, 2013 9:48 AM MDT Brent Watson wrote: >> > > >> > > >Joe, >> > > > >> > > >They can't both be Perseids. They are coming from different >> directions. >> > > I am not sure where the Perseid radiant is with respect to your >> > > photograph, but in fact neither may be a Perseid. Please check the >> > > direction of travel. The tracks also look pretty uniform. In fact, >> > almost >> > > too uniform to be meteors. Are they instead, satellites? >> > > > >> > > >> > _______________________________________________ >> > Utah-Astronomy mailing list >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > >> > Send messages to the list to >> > Utah-Astronomy(a)mailman.xmission.com >> > >> > The Utah-Astronomy mailing list is not affiliated with any astronomy >> club. >> > >> > To unsubscribe go to: >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > Then enter your email address in the space provided and click on >> > "Unsubscribe or edit options". >> > _______________________________________________ >> > Utah-Astronomy mailing list >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > >> > Send messages to the list to >> > Utah-Astronomy(a)mailman.xmission.com >> > >> > The Utah-Astronomy mailing list is not affiliated with any astronomy >> club. >> > >> > To unsubscribe go to: >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > Then enter your email address in the space provided and click on >> > "Unsubscribe or edit options". >> > _______________________________________________ >> > Utah-Astronomy mailing list >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > >> > Send messages to the list to >> > Utah-Astronomy(a)mailman.xmission.com >> > >> > The Utah-Astronomy mailing list is not affiliated with any astronomy >> club. >> > >> > To unsubscribe go to: >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > Then enter your email address in the space provided and click on >> > "Unsubscribe or edit options". >> > _______________________________________________ >> > Utah-Astronomy mailing list >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > >> > Send messages to the list to >> > Utah-Astronomy(a)mailman.xmission.com >> > >> > The Utah-Astronomy mailing list is not affiliated with any astronomy >> club. >> > >> > To unsubscribe go to: >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > Then enter your email address in the space provided and click on >> > "Unsubscribe or edit options". >> > _______________________________________________ >> > Utah-Astronomy mailing list >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > >> > Send messages to the list to >> > Utah-Astronomy(a)mailman.xmission.com >> > >> > The Utah-Astronomy mailing list is not affiliated with any astronomy >> club. >> > >> > To unsubscribe go to: >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > Then enter your email address in the space provided and click on >> > "Unsubscribe or edit options". >> > >> _______________________________________________ >> Utah-Astronomy mailing list >> http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> >> Send messages to the list to >> Utah-Astronomy(a)mailman.xmission.com >> >> The Utah-Astronomy mailing list is not affiliated with any astronomy club. >> >> To unsubscribe go to: >> http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> Then enter your email address in the space provided and click on >> "Unsubscribe or edit options". >> > > > >-- >Siegfried >_______________________________________________ >Utah-Astronomy mailing list >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy > >Send messages to the list to >Utah-Astronomy(a)mailman.xmission.com > >The Utah-Astronomy mailing list is not affiliated with any astronomy club. > >To unsubscribe go to: >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >Then enter your email address in the space provided and click on "Unsubscribe or edit options".

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WHITE FLAG -- was Galaxy NGC 6946 through smoke and meteriors
by Joe Bauman 17 Aug '13

17 Aug '13

OK OK I admit I was wrong. But I think one of my two streaked subexposures may have been a Perseid. Maybe this debate was only because of my directional dydlexia. -- Joe ------------------------------ On Sat, Aug 17, 2013 7:09 PM MDT Jared Smith wrote: >Sorry Joe, but this photo proves that you're incorrect. It shows a >bunch of Perseids and one non-Perseid. Because the Perseids all >originate from the same point, no matter what time of night a photo is >taken, a Perseid will always pass through the same point of sky at the >same angle. > >http://i.imgur.com/lVyDxEF.jpg > >Above is an illustration showing the radiant from Perseus to Andromeda >Galaxy (green line) and also from Polaris to Andromeda Galaxy (red >line) at both late night and early morning. No matter the time, the >Perseid will pass through Andromeda following the same path relative >to true north (55.8º angle between the two lines in both examples). If >you follow a straight line from point A to point B you can only >intersect point B at exactly one angle relative to point B. > >Jared > >On Sat, Aug 17, 2013 at 5:28 PM, Joe Bauman <josephmbauman(a)yahoo.com> wrote: >> >> OK, I would like to know what you non-roadblacks think of this. It clearly shows Perseid mterors traveling in different vectors. Look especially at the one aimed at the top of the mountain and the one right below it. Draw their trajectories back a short distance and they would actually cross. If someone were taking a several-minutes exposure of the galaxy and got a photo of both trails, Chuck would claim they weren't Perseids. What you fail to understand is that the dust forms a broad river above the atmosphere and the dust grains can intersect the river at many points and enter the atmosphere in many directions. To quote you, if you can't accept this simple fact or believe this photo, there's just no sense in arguing. -- Joe >> >> >> http://www.google.com/imgres?imgurl=http://i.space.com/images/i/000/020/498… >> >> ------------------------------ >> On Sat, Aug 17, 2013 4:14 PM MDT Chuck Hards wrote: >> >>You are battling a conceptual roadblock, Joe. The radiant does rotate with >>the stars as the earth turns. You need to bone-up on meteor showers and >>the way a radiant works as seen from the ground. >> >>This discussion is pointless until then. >>On Aug 17, 2013 4:02 PM, "Joe Bauman" <josephmbauman(a)yahoo.com> wrote: >> >>> >>> >>> No, the radiant does change because it comes from an essentially unmoving >>> stream of dust particles in space generally toward the northeast. As Earn >>> rotates relative yo this stream different sections of the atmosphere impact >>> it. The stream is a physical trail that the Earth bumps against as Earth >>> turns. >>> >>> >>> ------------------------------ >>> On Sat, Aug 17, 2013 3:46 PM MDT Chuck Hards wrote: >>> >>> >What you are forgetting, Joe, is that the radiant is rotating with the sky >>> >as well. The relationship between the target galaxy and the radiant >>> >doesn't change. >>> > On Aug 17, 2013 3:19 PM, "Joe Bauman" <josephmbauman(a)yahoo.com> wrote: >>> > >>> > >>> > >>> > Field rotation is relative to the observer on Earth -- true. But the >>> > tracking telescope compensates for it, meaning that the view in the >>> camera >>> > actually rotates as the camera does. A shot fired across the view from >>> the >>> > northeast part of the sky -- the trail of a Perseid metetor -- will cut >>> > across the frame at one direction. When the camera has rotated for half >>> an >>> > hour a shot from the same northeastern section would seem to cross the >>> > frame at a different angle. The stream of dust is still coming from the >>> > northeast but the galaxy has rotated a certain amount relative to it. >>> The >>> > distance of the target from the North Star will dictate how much >>> difference >>> > there is. -- Joe >>> > >>> > >>> > ------------------------------ >>> > On Sat, Aug 17, 2013 2:33 PM MDT Chuck Hards wrote: >>> > >>> > >But they do not rotate relative to the RA/DEC coordinate grid, which is >>> > the >>> > >crux of this discussion. Field rotation, which is rotation relative >>> to an >>> > >observer on earth, has nothing to do with it. You keep invoking it >>> Joe, >>> > >and It's really outside the matter of determining if a meteor is a >>> Perseid >>> > >or not. >>> > > >>> > >Brent is correct. >>> > >On Aug 17, 2013 2:23 PM, "Joe Bauman" <josephmbauman(a)yahoo.com> wrote: >>> > > >>> > > >>> > > Right, but celectial objects do rotate relative to that line. -- Joe >>> > > >>> > > >>> > > >>> > > ------------------------------ >>> > > On Sat, Aug 17, 2013 10:15 AM MDT Chuck Hards wrote: >>> > > >>> > > >Brent, I think Joe is just having trouble with polar coordinates. >>> > > >Joe, a straight line on the sky will always project as a curve on a >>> > > >2-dimensional computer screen, unless extremely short. >>> > > > On Aug 17, 2013 9:23 AM, "Brent Watson" <brentjwatson(a)yahoo.com> >>> > wrote: >>> > > > >>> > > > Joe, >>> > > > >>> > > > I think we have to agree to disagree. A perseid can never come from >>> > the >>> > > > North Star. Likewise, north in your photo will always be north, and >>> > the >>> > > > direction the galaxy is facing relative to celestial north will not >>> > > change. >>> > > > Your exercise of putting a piece of paper on your screen is not >>> > valid >>> > > > either. I am at a loss to be able to explain this unless we sit >>> down >>> > > > together and use some visual aids, so lets agree to disagree. >>> > > > >>> > > > Brent >>> > > > >>> > > > >>> > > > ________________________________ >>> > > > From: Joe Bauman <josephmbauman(a)yahoo.com> >>> > > > To: Utah Astronomy <utah-astronomy(a)mailman.xmission.com> >>> > > > Sent: Friday, August 16, 2013 11:38 PM >>> > > > Subject: Re: [Utah-astronomy] Galaxy NGC 6946 through smoke and >>> > > meteriors >>> > > > >>> > > > >>> > > > That's just not entirely true, Brent. The galaxy itself appears to >>> > > rotate >>> > > > as the night progresses, even minute by minute, just as the moon >>> ends >>> > > > upside down at sunrise from what it was at sunset. Let's remember >>> > first >>> > > > that the Perseids aren't really coming from Perseus but from a >>> stream >>> > of >>> > > > dust through which Earth passes. The dust doesn't rotate as Earth >>> > does. >>> > > > Then do this thought experiment: pretend you're a meteor that's >>> going >>> > to >>> > > > flash into our atmosphere from the direction of the North Star and >>> > cross >>> > > > the whole sky. If you do that in the middle of the night you cross a >>> > > > certain number of constellations that are up at that time. But if >>> you >>> > > > decide to zoom in 12 hours later, during the day, you will cross an >>> > > > entirely different set of (unseen to Earthlings) constellations. The >>> > > entry >>> > > > point was the same place and the angle of entry was the same but the >>> > > > trajectory crossed entirely different locations. If you vary that by >>> > an >>> > > > hour instead of half a day you still >>> > > > get a different track. A galaxy rotates as it crosses the sky just >>> the >>> > > way >>> > > > the moon does. I got my planetarium program going and I put the edge >>> > of >>> > > a >>> > > > piece of paper from NGC6946 to Perseus. Then I advanced the time by >>> > > half an >>> > > > hour. The galaxy rotated considerably in that time while I kept the >>> > > paper >>> > > > pointed at Perseus. In half an hour the direction that the Perseid >>> > > meteors >>> > > > streak across the galaxy changes. -- Joe >>> > > > >>> > > > >>> > > > >>> > > > ________________________________ >>> > > > From: Brent Watson <brentjwatson(a)yahoo.com> >>> > > > To: Utah Astronomy <utah-astronomy(a)mailman.xmission.com> >>> > > > Sent: Friday, August 16, 2013 9:31 PM >>> > > > Subject: Re: [Utah-astronomy] Galaxy NGC 6946 through smoke and >>> > > meteriors >>> > > > >>> > > > >>> > > > Joe, >>> > > > >>> > > > The whole sky rotates at the same rate. It rotates very close to 1 >>> > hour >>> > > > of right ascension per hour of mean solar time, as measured by your >>> > > watch. >>> > > > The angle between the radiant and the galaxy will not change, >>> > > neglecting >>> > > > the movement of the radiant itself. (That movement happens over >>> days, >>> > > not >>> > > > minutes.) Both of those traces cannot be due to Perseid meteors >>> > > because of >>> > > > the angle formed by the two traces. One of them MAY be, but the >>> other >>> > > is >>> > > > certainly not. How does the the line from the radiant intersect NGC >>> > > 6946 >>> > > > as seen on your digital planetarium? Does it pass through at the >>> same >>> > > > angle as one of the traces? If not, then both are either sporadic >>> or >>> > > not >>> > > > meteors at all. >>> > > > >>> > > > Brent >>> > > > >>> > > > >>> > > > ________________________________ >>> > > > From: Joe Bauman <josephmbauman(a)yahoo.com> >>> > > > To: Utah Astronomy <utah-astronomy(a)mailman.xmission.com> >>> > > > Sent: Friday, August 16, 2013 6:09 PM >>> > > > Subject: Re: [Utah-astronomy] Galaxy NGC 6946 through smoke and >>> > > meteriors >>> > > > >>> > > > >>> > > > Looking at my computerized planetarium, it's certainly possible to >>> > draw >>> > > a >>> > > > radiant from Perseus to NGC 6946 at the time I took the views, about >>> > > 3:14 >>> > > > and 3:44 a.m., respectively, on Wednesday morning. I haven't had >>> time >>> > to >>> > > > figure it out formally yet, but by running my planetarium program >>> from >>> > > the >>> > > > first to the second time it looks like NGC 6946 revolves about the >>> > same >>> > > > amount as the difference in the lines in the two subs. Because they >>> > are >>> > > in >>> > > > different sections of the sky, the galaxy and the constellation >>> > revolve >>> > > at >>> > > > different rates. So unless someone wants to be a lot more scientific >>> > > about >>> > > > calculating >>> > > > these things and proves me wrong, I will continue to believe they >>> are >>> > > both >>> > > > Perseids. -- Joe >>> > > > >>> > > > >>> > > > >>> > > > >>> > > > ________________________________ >>> > > > From: Chuck Hards <chuck.hards(a)gmail.com> >>> > > > To: Utah Astronomy <utah-astronomy(a)mailman.xmission.com> >>> > > > Sent: Friday, August 16, 2013 4:40 PM >>> > > > Subject: Re: [Utah-astronomy] Galaxy NGC 6946 through smoke and >>> > > meteriors >>> > > > >>> > > > >>> > > > For the meteors to be considered Perseids, they must have radiated >>> > from >>> > > the >>> > > > Perseid radiant. They can appear anywhere in the sky, and at any >>> > angle >>> > > > relative to the observer, but in order to be a member of a given >>> > > shower, if >>> > > > you extend their path backwards across the sky, it must intersect >>> the >>> > > > radiant. If it doesn't, it's a sporadic, or a member of a different >>> > > > shower. Some showers do overlap their times of activity. >>> > > > >>> > > > All members of a given shower hit the earth's atmosphere at the same >>> > > > angle. They are traveling parallel in space. It just looks >>> different >>> > > to a >>> > > > ground-based observer. >>> > > > >>> > > > Imagine the radiant as a sort of "vanishing point" in the sky. >>> > > > >>> > > > On Fri, Aug 16, 2013 at 2:25 PM, Joe Bauman < >>> josephmbauman(a)yahoo.com> >>> > > > wrote: >>> > > > >>> > > > > >>> > > > > >>> > > > > >>> > > > > I did consult a star atlas ant I think they could be perseids -- >>> > > > > meteorites seem to show up at various parts of the sky, not >>> > > necessarily >>> > > > > heading from Perseus directly. It is a wide stream of cometary >>> dust >>> > > that >>> > > > > yge Earth passes through and I reckon that the atmosphere may hit >>> > the >>> > > > dust >>> > > > > grains at various angles. Also saying the tracks look too uniform >>> > > isn't a >>> > > > > good way to judge them when you consider the field of view is tiny >>> > -- >>> > > in >>> > > > a >>> > > > > larger field they may have been less regular over s lmgrt stretch >>> of >>> > > > their >>> > > > > entry path. Well, that's my story and I'm stickin' with if! -- >>> > Thanks, >>> > > > Joe >>> > > > > >>> > > > > ------------------------------ >>> > > > > On Fri, Aug 16, 2013 9:48 AM MDT Brent Watson wrote: >>> > > > > >>> > > > > >Joe, >>> > > > > > >>> > > > > >They can't both be Perseids. They are coming from different >>> > > directions. >>> > > > > I am not sure where the Perseid radiant is with respect to your >>> > > > > photograph, but in fact neither may be a Perseid. Please check >>> the >>> > > > > direction of travel. The tracks also look pretty uniform. In >>> fact, >>> > > > almost >>> > > > > too uniform to be meteors. Are they instead, satellites? >>> > > > > > >>> > > > > >>> > > > _______________________________________________ >>> > > > Utah-Astronomy mailing list >>> > > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> > > > >>> > > > Send messages to the list to >>> > > > Utah-Astronomy(a)mailman.xmission.com >>> > > > >>> > > > The Utah-Astronomy mailing list is not affiliated with any astronomy >>> > > club. >>> > > > >>> > > > To unsubscribe go to: >>> > > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> > > > Then enter your email address in the space provided and click on >>> > > > "Unsubscribe or edit options". >>> > > > _______________________________________________ >>> > > > Utah-Astronomy mailing list >>> > > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> > > > >>> > > > Send messages to the list to >>> > > > Utah-Astronomy(a)mailman.xmission.com >>> > > > >>> > > > The Utah-Astronomy mailing list is not affiliated with any astronomy >>> > > club. >>> > > > >>> > > > To unsubscribe go to: >>> > > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> > > > Then enter your email address in the space provided and click on >>> > > > "Unsubscribe or edit options". >>> > > > _______________________________________________ >>> > > > Utah-Astronomy mailing list >>> > > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> > > > >>> > > > Send messages to the list to >>> > > > Utah-Astronomy(a)mailman.xmission.com >>> > > > >>> > > > The Utah-Astronomy mailing list is not affiliated with any astronomy >>> > > club. >>> > > > >>> > > > To unsubscribe go to: >>> > > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> > > > Then enter your email address in the space provided and click on >>> > > > "Unsubscribe or edit options". >>> > > > _______________________________________________ >>> > > > Utah-Astronomy mailing list >>> > > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> > > > >>> > > > Send messages to the list to >>> > > > Utah-Astronomy(a)mailman.xmission.com >>> > > > >>> > > > The Utah-Astronomy mailing list is not affiliated with any astronomy >>> > > club. >>> > > > >>> > > > To unsubscribe go to: >>> > > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> > > > Then enter your email address in the space provided and click on >>> > > > "Unsubscribe or edit options". >>> > > > _______________________________________________ >>> > > > Utah-Astronomy mailing list >>> > > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> > > > >>> > > > Send messages to the list to >>> > > > Utah-Astronomy(a)mailman.xmission.com >>> > > > >>> > > > The Utah-Astronomy mailing list is not affiliated with any astronomy >>> > > club. >>> > > > >>> > > > To unsubscribe go to: >>> > > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> > > > Then enter your email address in the space provided and click on >>> > > > "Unsubscribe or edit options". >>> > > > >>> > > >_______________________________________________ >>> > > >Utah-Astronomy mailing list >>> > > >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> > > > >>> > > >Send messages to the list to >>> > > >Utah-Astronomy(a)mailman.xmission.com >>> > > > >>> > > >The Utah-Astronomy mailing list is not affiliated with any astronomy >>> > club. >>> > > > >>> > > >To unsubscribe go to: >>> > > >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> > > >Then enter your email address in the space provided and click on >>> > > "Unsubscribe or edit options". >>> > > >>> > > >>> > > _______________________________________________ >>> > > Utah-Astronomy mailing list >>> > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> > > >>> > > Send messages to the list to >>> > > Utah-Astronomy(a)mailman.xmission.com >>> > > >>> > > The Utah-Astronomy mailing list is not affiliated with any astronomy >>> > club. >>> > > >>> > > To unsubscribe go to: >>> > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> > > Then enter your email address in the space provided and click on >>> > > "Unsubscribe or edit options". >>> > > >>> > >_______________________________________________ >>> > >Utah-Astronomy mailing list >>> > >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> > > >>> > >Send messages to the list to >>> > >Utah-Astronomy(a)mailman.xmission.com >>> > > >>> > >The Utah-Astronomy mailing list is not affiliated with any astronomy >>> club. >>> > > >>> > >To unsubscribe go to: >>> > >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> > >Then enter your email address in the space provided and click on >>> > "Unsubscribe or edit options". >>> > >>> > >>> > _______________________________________________ >>> > Utah-Astronomy mailing list >>> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> > >>> > Send messages to the list to >>> > Utah-Astronomy(a)mailman.xmission.com >>> > >>> > The Utah-Astronomy mailing list is not affiliated with any astronomy >>> club. >>> > >>> > To unsubscribe go to: >>> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> > Then enter your email address in the space provided and click on >>> > "Unsubscribe or edit options". >>> > >>> >_______________________________________________ >>> >Utah-Astronomy mailing list >>> >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> > >>> >Send messages to the list to >>> >Utah-Astronomy(a)mailman.xmission.com >>> > >>> >The Utah-Astronomy mailing list is not affiliated with any astronomy club. >>> > >>> >To unsubscribe go to: >>> >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> >Then enter your email address in the space provided and click on >>> "Unsubscribe or edit options". >>> >>> >>> _______________________________________________ >>> Utah-Astronomy mailing list >>> http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> >>> Send messages to the list to >>> Utah-Astronomy(a)mailman.xmission.com >>> >>> The Utah-Astronomy mailing list is not affiliated with any astronomy club. >>> >>> To unsubscribe go to: >>> http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> Then enter your email address in the space provided and click on >>> "Unsubscribe or edit options". >>> >>_______________________________________________ >>Utah-Astronomy mailing list >>http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> >>Send messages to the list to >>Utah-Astronomy(a)mailman.xmission.com >> >>The Utah-Astronomy mailing list is not affiliated with any astronomy club. >> >>To unsubscribe go to: >>http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>Then enter your email address in the space provided and click on "Unsubscribe or edit options". >> >> >> _______________________________________________ >> Utah-Astronomy mailing list >> http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> >> Send messages to the list to >> Utah-Astronomy(a)mailman.xmission.com >> >> The Utah-Astronomy mailing list is not affiliated with any astronomy club. >> >> To unsubscribe go to: >> http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> Then enter your email address in the space provided and click on "Unsubscribe or edit options". > >_______________________________________________ >Utah-Astronomy mailing list >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy > >Send messages to the list to >Utah-Astronomy(a)mailman.xmission.com > >The Utah-Astronomy mailing list is not affiliated with any astronomy club. > >To unsubscribe go to: >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >Then enter your email address in the space provided and click on "Unsubscribe or edit options".

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Re: [Utah-astronomy] Galaxy NGC 6946 through smoke and meteriors
by Joe Bauman 17 Aug '13

17 Aug '13

Well let's say I'm exploring ideas I don't fully understand yet. -- Joe ------------------------------ On Sat, Aug 17, 2013 6:28 PM MDT daniel turner wrote: >Joe: >you are wrong and Brent, Chuck, and Sigfried are correct. You are arguing from a couple of misconceptions. Bravely and vigorously, but still wrong none the less. > >DT >_______________________________________________ >Utah-Astronomy mailing list >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy > >Send messages to the list to >Utah-Astronomy(a)mailman.xmission.com > >The Utah-Astronomy mailing list is not affiliated with any astronomy club. > >To unsubscribe go to: >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >Then enter your email address in the space provided and click on "Unsubscribe or edit options".

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Re: [Utah-astronomy] WHITE FLAG -- was Galaxy NGC 6946 through smoke and meteriors
by Joe Bauman 17 Aug '13

17 Aug '13

Well, rats. ------------------------------ On Sat, Aug 17, 2013 7:48 PM MDT Jared Smith wrote: >:-) It's all good. This was actually a really good thought experiment. >I had to really think through it and draw things out myself (and even >then I wasn't absolutely sure). > >As I examine the angle at which the objects passed through the galaxy >(assuming the orientation of NGC6946 in Stellarium is correct - which >it usually is), both were at almost 90 degree angles to Perseus. This >would make it quite unlikely for them to be Perseids. For what it's >worth, I think it most likely that they are satellites, but we'll >never know for sure. > >Jared > >On Sat, Aug 17, 2013 at 7:18 PM, Joe Bauman <josephmbauman(a)yahoo.com> wrote: >> >> OK OK I admit I was wrong. But I think one of my two streaked subexposures may have been a Perseid. Maybe this debate was only because of my directional dydlexia. -- Joe >> >> >> ------------------------------ >> On Sat, Aug 17, 2013 7:09 PM MDT Jared Smith wrote: >> >>Sorry Joe, but this photo proves that you're incorrect. It shows a >>bunch of Perseids and one non-Perseid. Because the Perseids all >>originate from the same point, no matter what time of night a photo is >>taken, a Perseid will always pass through the same point of sky at the >>same angle. >> >>http://i.imgur.com/lVyDxEF.jpg >> >>Above is an illustration showing the radiant from Perseus to Andromeda >>Galaxy (green line) and also from Polaris to Andromeda Galaxy (red >>line) at both late night and early morning. No matter the time, the >>Perseid will pass through Andromeda following the same path relative >>to true north (55.8º angle between the two lines in both examples). If >>you follow a straight line from point A to point B you can only >>intersect point B at exactly one angle relative to point B. >> >>Jared >> >>On Sat, Aug 17, 2013 at 5:28 PM, Joe Bauman <josephmbauman(a)yahoo.com> wrote: >>> >>> OK, I would like to know what you non-roadblacks think of this. It clearly shows Perseid mterors traveling in different vectors. Look especially at the one aimed at the top of the mountain and the one right below it. Draw their trajectories back a short distance and they would actually cross. If someone were taking a several-minutes exposure of the galaxy and got a photo of both trails, Chuck would claim they weren't Perseids. What you fail to understand is that the dust forms a broad river above the atmosphere and the dust grains can intersect the river at many points and enter the atmosphere in many directions. To quote you, if you can't accept this simple fact or believe this photo, there's just no sense in arguing. -- Joe >>> >>> >>> http://www.google.com/imgres?imgurl=http://i.space.com/images/i/000/020/498… >>> >>> ------------------------------ >>> On Sat, Aug 17, 2013 4:14 PM MDT Chuck Hards wrote: >>> >>>You are battling a conceptual roadblock, Joe. The radiant does rotate with >>>the stars as the earth turns. You need to bone-up on meteor showers and >>>the way a radiant works as seen from the ground. >>> >>>This discussion is pointless until then. >>>On Aug 17, 2013 4:02 PM, "Joe Bauman" <josephmbauman(a)yahoo.com> wrote: >>> >>> >>> >>> No, the radiant does change because it comes from an essentially unmoving >>> stream of dust particles in space generally toward the northeast. As Earn >>> rotates relative yo this stream different sections of the atmosphere impact >>> it. The stream is a physical trail that the Earth bumps against as Earth >>> turns. >>> >>> >>> ------------------------------ >>> On Sat, Aug 17, 2013 3:46 PM MDT Chuck Hards wrote: >>> >>> >What you are forgetting, Joe, is that the radiant is rotating with the sky >>> >as well. The relationship between the target galaxy and the radiant >>> >doesn't change. >>> > On Aug 17, 2013 3:19 PM, "Joe Bauman" <josephmbauman(a)yahoo.com> wrote: >>> > >>> > >>> > >>> > Field rotation is relative to the observer on Earth -- true. But the >>> > tracking telescope compensates for it, meaning that the view in the >>> camera >>> > actually rotates as the camera does. A shot fired across the view from >>> the >>> > northeast part of the sky -- the trail of a Perseid metetor -- will cut >>> > across the frame at one direction. When the camera has rotated for half >>> an >>> > hour a shot from the same northeastern section would seem to cross the >>> > frame at a different angle. The stream of dust is still coming from the >>> > northeast but the galaxy has rotated a certain amount relative to it. >>> The >>> > distance of the target from the North Star will dictate how much >>> difference >>> > there is. -- Joe >>> > >>> > >>> > ------------------------------ >>> > On Sat, Aug 17, 2013 2:33 PM MDT Chuck Hards wrote: >>> > >>> > >But they do not rotate relative to the RA/DEC coordinate grid, which is >>> > the >>> > >crux of this discussion. Field rotation, which is rotation relative >>> to an >>> > >observer on earth, has nothing to do with it. You keep invoking it >>> Joe, >>> > >and It's really outside the matter of determining if a meteor is a >>> Perseid >>> > >or not. >>> > > >>> > >Brent is correct. >>> > >On Aug 17, 2013 2:23 PM, "Joe Bauman" <josephmbauman(a)yahoo.com> wrote: >>> > > >>> > > >>> > > Right, but celectial objects do rotate relative to that line. -- Joe >>> > > >>> > > >>> > > >>> > > ------------------------------ >>> > > On Sat, Aug 17, 2013 10:15 AM MDT Chuck Hards wrote: >>> > > >>> > > >Brent, I think Joe is just having trouble with polar coordinates. >>> > > >Joe, a straight line on the sky will always project as a curve on a >>> > > >2-dimensional computer screen, unless extremely short. >>> > > > On Aug 17, 2013 9:23 AM, "Brent Watson" <brentjwatson(a)yahoo.com> >>> > wrote: >>> > > > >>> > > > Joe, >>> > > > >>> > > > I think we have to agree to disagree. A perseid can never come from >>> > the >>> > > > North Star. Likewise, north in your photo will always be north, and >>> > the >>> > > > direction the galaxy is facing relative to celestial north will not >>> > > change. >>> > > > Your exercise of putting a piece of paper on your screen is not >>> > valid >>> > > > either. I am at a loss to be able to explain this unless we sit >>> down >>> > > > together and use some visual aids, so lets agree to disagree. >>> > > > >>> > > > Brent >>> > > > >>> > > > >>> > > > ________________________________ >>> > > > From: Joe Bauman <josephmbauman(a)yahoo.com> >>> > > > To: Utah Astronomy <utah-astronomy(a)mailman.xmission.com> >>> > > > Sent: Friday, August 16, 2013 11:38 PM >>> > > > Subject: Re: [Utah-astronomy] Galaxy NGC 6946 through smoke and >>> > > meteriors >>> > > > >>> > > > >>> > > > That's just not entirely true, Brent. The galaxy itself appears to >>> > > rotate >>> > > > as the night progresses, even minute by minute, just as the moon >>> ends >>> > > > upside down at sunrise from what it was at sunset. Let's remember >>> > first >>> > > > that the Perseids aren't really coming from Perseus but from a >>> stream >>> > of >>> > > > dust through which Earth passes. The dust doesn't rotate as Earth >>> > does. >>> > > > Then do this thought experiment: pretend you're a meteor that's >>> going >>> > to >>> > > > flash into our atmosphere from the direction of the North Star and >>> > cross >>> > > > the whole sky. If you do that in the middle of the night you cross a >>> > > > certain number of constellations that are up at that time. But if >>> you >>> > > > decide to zoom in 12 hours later, during the day, you will cross an >>> > > > entirely different set of (unseen to Earthlings) constellations. The >>> > > entry >>> > > > point was the same place and the angle of entry was the same but the >>> > > > trajectory crossed entirely different locations. If you vary that by >>> > an >>> > > > hour instead of half a day you still >>> > > > get a different track. A galaxy rotates as it crosses the sky just >>> the >>> > > way >>> > > > the moon does. I got my planetarium program going and I put the edge >>> > of >>> > > a >>> > > > piece of paper from NGC6946 to Perseus. Then I advanced the time by >>> > > half an >>> > > > hour. The galaxy rotated considerably in that time while I kept the >>> > > paper >>> > > > pointed at Perseus. In half an hour the direction that the Perseid >>> > > meteors >>> > > > streak across the galaxy changes. -- Joe >>> > > > >>> > > > >>> > > > >>> > > > ________________________________ >>> > > > From: Brent Watson <brentjwatson(a)yahoo.com> >>> > > > To: Utah Astronomy <utah-astronomy(a)mailman.xmission.com> >>> > > > Sent: Friday, August 16, 2013 9:31 PM >>> > > > Subject: Re: [Utah-astronomy] Galaxy NGC 6946 through smoke and >>> > > meteriors >>> > > > >>> > > > >>> > > > Joe, >>> > > > >>> > > > The whole sky rotates at the same rate. It rotates very close to 1 >>> > hour >>> > > > of right ascension per hour of mean solar time, as measured by your >>> > > watch. >>> > > > The angle between the radiant and the galaxy will not change, >>> > > neglecting >>> > > > the movement of the radiant itself. (That movement happens over >>> days, >>> > > not >>> > > > minutes.) Both of those traces cannot be due to Perseid meteors >>> > > because of >>> > > > the angle formed by the two traces. One of them MAY be, but the >>> other >>> > > is >>> > > > certainly not. How does the the line from the radiant intersect NGC >>> > > 6946 >>> > > > as seen on your digital planetarium? Does it pass through at the >>> same >>> > > > angle as one of the traces? If not, then both are either sporadic >>> or >>> > > not >>> > > > meteors at all. >>> > > > >>> > > > Brent >>> > > > >>> > > > >>> > > > ________________________________ >>> > > > From: Joe Bauman <josephmbauman(a)yahoo.com> >>> > > > To: Utah Astronomy <utah-astronomy(a)mailman.xmission.com> >>> > > > Sent: Friday, August 16, 2013 6:09 PM >>> > > > Subject: Re: [Utah-astronomy] Galaxy NGC 6946 through smoke and >>> > > meteriors >>> > > > >>> > > > >>> > > > Looking at my computerized planetarium, it's certainly possible to >>> > draw >>> > > a >>> > > > radiant from Perseus to NGC 6946 at the time I took the views, about >>> > > 3:14 >>> > > > and 3:44 a.m., respectively, on Wednesday morning. I haven't had >>> time >>> > to >>> > > > figure it out formally yet, but by running my planetarium program >>> from >>> > > the >>> > > > first to the second time it looks like NGC 6946 revolves about the >>> > same >>> > > > amount as the difference in the lines in the two subs. Because they >>> > are >>> > > in >>> > > > different sections of the sky, the galaxy and the constellation >>> > revolve >>> > > at >>> > > > different rates. So unless someone wants to be a lot more scientific >>> > > about >>> > > > calculating >>> > > > these things and proves me wrong, I will continue to believe they >>> are >>> > > both >>> > > > Perseids. -- Joe >>> > > > >>> > > > >>> > > > >>> > > > >>> > > > ________________________________ >>> > > > From: Chuck Hards <chuck.hards(a)gmail.com> >>> > > > To: Utah Astronomy <utah-astronomy(a)mailman.xmission.com> >>> > > > Sent: Friday, August 16, 2013 4:40 PM >>> > > > Subject: Re: [Utah-astronomy] Galaxy NGC 6946 through smoke and >>> > > meteriors >>> > > > >>> > > > >>> > > > For the meteors to be considered Perseids, they must have radiated >>> > from >>> > > the >>> > > > Perseid radiant. They can appear anywhere in the sky, and at any >>> > angle >>> > > > relative to the observer, but in order to be a member of a given >>> > > shower, if >>> > > > you extend their path backwards across the sky, it must intersect >>> the >>> > > > radiant. If it doesn't, it's a sporadic, or a member of a different >>> > > > shower. Some showers do overlap their times of activity. >>> > > > >>> > > > All members of a given shower hit the earth's atmosphere at the same >>> > > > angle. They are traveling parallel in space. It just looks >>> different >>> > > to a >>> > > > ground-based observer. >>> > > > >>> > > > Imagine the radiant as a sort of "vanishing point" in the sky. >>> > > > >>> > > > On Fri, Aug 16, 2013 at 2:25 PM, Joe Bauman < >>> josephmbauman(a)yahoo.com> >>> > > > wrote: >>> > > > >>> > > > > >>> > > > > >>> > > > > >>> > > > > I did consult a star atlas ant I think they could be perseids -- >>> > > > > meteorites seem to show up at various parts of the sky, not >>> > > necessarily >>> > > > > heading from Perseus directly. It is a wide stream of cometary >>> dust >>> > > that >>> > > > > yge Earth passes through and I reckon that the atmosphere may hit >>> > the >>> > > > dust >>> > > > > grains at various angles. Also saying the tracks look too uniform >>> > > isn't a >>> > > > > good way to judge them when you consider the field of view is tiny >>> > -- >>> > > in >>> > > > a >>> > > > > larger field they may have been less regular over s lmgrt stretch >>> of >>> > > > their >>> > > > > entry path. Well, that's my story and I'm stickin' with if! -- >>> > Thanks, >>> > > > Joe >>> > > > > >>> > > > > ------------------------------ >>> > > > > On Fri, Aug 16, 2013 9:48 AM MDT Brent Watson wrote: >>> > > > > >>> > > > > >Joe, >>> > > > > > >>> > > > > >They can't both be Perseids. They are coming from different >>> > > directions. >>> > > > > I am not sure where the Perseid radiant is with respect to your >>> > > > > photograph, but in fact neither may be a Perseid. Please check >>> the >>> > > > > direction of travel. The tracks also look pretty uniform. In >>> fact, >>> > > > almost >>> > > > > too uniform to be meteors. Are they instead, satellites? >>> > > > > > >>> > > > > >>> > > > _______________________________________________ >>> > > > Utah-Astronomy mailing list >>> > > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> > > > >>> > > > Send messages to the list to >>> > > > Utah-Astronomy(a)mailman.xmission.com >>> > > > >>> > > > The Utah-Astronomy mailing list is not affiliated with any astronomy >>> > > club. >>> > > > >>> > > > To unsubscribe go to: >>> > > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> > > > Then enter your email address in the space provided and click on >>> > > > "Unsubscribe or edit options". >>> > > > _______________________________________________ >>> > > > Utah-Astronomy mailing list >>> > > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> > > > >>> > > > Send messages to the list to >>> > > > Utah-Astronomy(a)mailman.xmission.com >>> > > > >>> > > > The Utah-Astronomy mailing list is not affiliated with any astronomy >>> > > club. >>> > > > >>> > > > To unsubscribe go to: >>> > > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> > > > Then enter your email address in the space provided and click on >>> > > > "Unsubscribe or edit options". >>> > > > _______________________________________________ >>> > > > Utah-Astronomy mailing list >>> > > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> > > > >>> > > > Send messages to the list to >>> > > > Utah-Astronomy(a)mailman.xmission.com >>> > > > >>> > > > The Utah-Astronomy mailing list is not affiliated with any astronomy >>> > > club. >>> > > > >>> > > > To unsubscribe go to: >>> > > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> > > > Then enter your email address in the space provided and click on >>> > > > "Unsubscribe or edit options". >>> > > > _______________________________________________ >>> > > > Utah-Astronomy mailing list >>> > > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> > > > >>> > > > Send messages to the list to >>> > > > Utah-Astronomy(a)mailman.xmission.com >>> > > > >>> > > > The Utah-Astronomy mailing list is not affiliated with any astronomy >>> > > club. >>> > > > >>> > > > To unsubscribe go to: >>> > > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> > > > Then enter your email address in the space provided and click on >>> > > > "Unsubscribe or edit options". >>> > > > _______________________________________________ >>> > > > Utah-Astronomy mailing list >>> > > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> > > > >>> > > > Send messages to the list to >>> > > > Utah-Astronomy(a)mailman.xmission.com >>> > > > >>> > > > The Utah-Astronomy mailing list is not affiliated with any astronomy >>> > > club. >>> > > > >>> > > > To unsubscribe go to: >>> > > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> > > > Then enter your email address in the space provided and click on >>> > > > "Unsubscribe or edit options". >>> > > > >>> > > >_______________________________________________ >>> > > >Utah-Astronomy mailing list >>> > > >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> > > > >>> > > >Send messages to the list to >>> > > >Utah-Astronomy(a)mailman.xmission.com >>> > > > >>> > > >The Utah-Astronomy mailing list is not affiliated with any astronomy >>> > club. >>> > > > >>> > > >To unsubscribe go to: >>> > > >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> > > >Then enter your email address in the space provided and click on >>> > > "Unsubscribe or edit options". >>> > > >>> > > >>> > > _______________________________________________ >>> > > Utah-Astronomy mailing list >>> > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> > > >>> > > Send messages to the list to >>> > > Utah-Astronomy(a)mailman.xmission.com >>> > > >>> > > The Utah-Astronomy mailing list is not affiliated with any astronomy >>> > club. >>> > > >>> > > To unsubscribe go to: >>> > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> > > Then enter your email address in the space provided and click on >>> > > "Unsubscribe or edit options". >>> > > >>> > >_______________________________________________ >>> > >Utah-Astronomy mailing list >>> > >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> > > >>> > >Send messages to the list to >>> > >Utah-Astronomy(a)mailman.xmission.com >>> > > >>> > >The Utah-Astronomy mailing list is not affiliated with any astronomy >>> club. >>> > > >>> > >To unsubscribe go to: >>> > >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> > >Then enter your email address in the space provided and click on >>> > "Unsubscribe or edit options". >>> > >>> > >>> > _______________________________________________ >>> > Utah-Astronomy mailing list >>> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> > >>> > Send messages to the list to >>> > Utah-Astronomy(a)mailman.xmission.com >>> > >>> > The Utah-Astronomy mailing list is not affiliated with any astronomy >>> club. >>> > >>> > To unsubscribe go to: >>> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> > Then enter your email address in the space provided and click on >>> > "Unsubscribe or edit options". >>> > >>> >_______________________________________________ >>> >Utah-Astronomy mailing list >>> >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> > >>> >Send messages to the list to >>> >Utah-Astronomy(a)mailman.xmission.com >>> > >>> >The Utah-Astronomy mailing list is not affiliated with any astronomy club. >>> > >>> >To unsubscribe go to: >>> >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> >Then enter your email address in the space provided and click on >>> "Unsubscribe or edit options". >>> >>> >>> _______________________________________________ >>> Utah-Astronomy mailing list >>> http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> >>> Send messages to the list to >>> Utah-Astronomy(a)mailman.xmission.com >>> >>> The Utah-Astronomy mailing list is not affiliated with any astronomy club. >>> >>> To unsubscribe go to: >>> http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> Then enter your email address in the space provided and click on >>> "Unsubscribe or edit options". >>> >>>_______________________________________________ >>>Utah-Astronomy mailing list >>>http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> >>>Send messages to the list to >>>Utah-Astronomy(a)mailman.xmission.com >>> >>>The Utah-Astronomy mailing list is not affiliated with any astronomy club. >>> >>>To unsubscribe go to: >>>http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>>Then enter your email address in the space provided and click on "Unsubscribe or edit options". >>> >>> >>> _______________________________________________ >>> Utah-Astronomy mailing list >>> http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> >>> Send messages to the list to >>> Utah-Astronomy(a)mailman.xmission.com >>> >>> The Utah-Astronomy mailing list is not affiliated with any astronomy club. >>> >>> To unsubscribe go to: >>> http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>> Then enter your email address in the space provided and click on "Unsubscribe or edit options". >> >>_______________________________________________ >>Utah-Astronomy mailing list >>http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> >>Send messages to the list to >>Utah-Astronomy(a)mailman.xmission.com >> >>The Utah-Astronomy mailing list is not affiliated with any astronomy club. >> >>To unsubscribe go to: >>http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >>Then enter your email address in the space provided and click on "Unsubscribe or edit options". >> >> >> _______________________________________________ >> Utah-Astronomy mailing list >> http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> >> Send messages to the list to >> Utah-Astronomy(a)mailman.xmission.com >> >> The Utah-Astronomy mailing list is not affiliated with any astronomy club. >> >> To unsubscribe go to: >> http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> Then enter your email address in the space provided and click on "Unsubscribe or edit options". > >_______________________________________________ >Utah-Astronomy mailing list >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy > >Send messages to the list to >Utah-Astronomy(a)mailman.xmission.com > >The Utah-Astronomy mailing list is not affiliated with any astronomy club. > >To unsubscribe go to: >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >Then enter your email address in the space provided and click on "Unsubscribe or edit options".

1 0

Re: [Utah-astronomy] Galaxy NGC 6946 through smoke and meteriors
by Joe Bauman 17 Aug '13

17 Aug '13

OK, I would like to know what you non-roadblacks think of this. It clearly shows Perseid mterors traveling in different vectors. Look especially at the one aimed at the top of the mountain and the one right below it. Draw their trajectories back a short distance and they would actually cross. If someone were taking a several-minutes exposure of the galaxy and got a photo of both trails, Chuck would claim they weren't Perseids. What you fail to understand is that the dust forms a broad river above the atmosphere and the dust grains can intersect the river at many points and enter the atmosphere in many directions. To quote you, if you can't accept this simple fact or believe this photo, there's just no sense in arguing. -- Joe http://www.google.com/imgres?imgurl=http://i.space.com/images/i/000/020/498… ------------------------------ On Sat, Aug 17, 2013 4:14 PM MDT Chuck Hards wrote: >You are battling a conceptual roadblock, Joe. The radiant does rotate with >the stars as the earth turns. You need to bone-up on meteor showers and >the way a radiant works as seen from the ground. > >This discussion is pointless until then. >On Aug 17, 2013 4:02 PM, "Joe Bauman" <josephmbauman(a)yahoo.com> wrote: > >> >> >> No, the radiant does change because it comes from an essentially unmoving >> stream of dust particles in space generally toward the northeast. As Earn >> rotates relative yo this stream different sections of the atmosphere impact >> it. The stream is a physical trail that the Earth bumps against as Earth >> turns. >> >> >> ------------------------------ >> On Sat, Aug 17, 2013 3:46 PM MDT Chuck Hards wrote: >> >> >What you are forgetting, Joe, is that the radiant is rotating with the sky >> >as well. The relationship between the target galaxy and the radiant >> >doesn't change. >> > On Aug 17, 2013 3:19 PM, "Joe Bauman" <josephmbauman(a)yahoo.com> wrote: >> > >> > >> > >> > Field rotation is relative to the observer on Earth -- true. But the >> > tracking telescope compensates for it, meaning that the view in the >> camera >> > actually rotates as the camera does. A shot fired across the view from >> the >> > northeast part of the sky -- the trail of a Perseid metetor -- will cut >> > across the frame at one direction. When the camera has rotated for half >> an >> > hour a shot from the same northeastern section would seem to cross the >> > frame at a different angle. The stream of dust is still coming from the >> > northeast but the galaxy has rotated a certain amount relative to it. >> The >> > distance of the target from the North Star will dictate how much >> difference >> > there is. -- Joe >> > >> > >> > ------------------------------ >> > On Sat, Aug 17, 2013 2:33 PM MDT Chuck Hards wrote: >> > >> > >But they do not rotate relative to the RA/DEC coordinate grid, which is >> > the >> > >crux of this discussion. Field rotation, which is rotation relative >> to an >> > >observer on earth, has nothing to do with it. You keep invoking it >> Joe, >> > >and It's really outside the matter of determining if a meteor is a >> Perseid >> > >or not. >> > > >> > >Brent is correct. >> > >On Aug 17, 2013 2:23 PM, "Joe Bauman" <josephmbauman(a)yahoo.com> wrote: >> > > >> > > >> > > Right, but celectial objects do rotate relative to that line. -- Joe >> > > >> > > >> > > >> > > ------------------------------ >> > > On Sat, Aug 17, 2013 10:15 AM MDT Chuck Hards wrote: >> > > >> > > >Brent, I think Joe is just having trouble with polar coordinates. >> > > >Joe, a straight line on the sky will always project as a curve on a >> > > >2-dimensional computer screen, unless extremely short. >> > > > On Aug 17, 2013 9:23 AM, "Brent Watson" <brentjwatson(a)yahoo.com> >> > wrote: >> > > > >> > > > Joe, >> > > > >> > > > I think we have to agree to disagree. A perseid can never come from >> > the >> > > > North Star. Likewise, north in your photo will always be north, and >> > the >> > > > direction the galaxy is facing relative to celestial north will not >> > > change. >> > > > Your exercise of putting a piece of paper on your screen is not >> > valid >> > > > either. I am at a loss to be able to explain this unless we sit >> down >> > > > together and use some visual aids, so lets agree to disagree. >> > > > >> > > > Brent >> > > > >> > > > >> > > > ________________________________ >> > > > From: Joe Bauman <josephmbauman(a)yahoo.com> >> > > > To: Utah Astronomy <utah-astronomy(a)mailman.xmission.com> >> > > > Sent: Friday, August 16, 2013 11:38 PM >> > > > Subject: Re: [Utah-astronomy] Galaxy NGC 6946 through smoke and >> > > meteriors >> > > > >> > > > >> > > > That's just not entirely true, Brent. The galaxy itself appears to >> > > rotate >> > > > as the night progresses, even minute by minute, just as the moon >> ends >> > > > upside down at sunrise from what it was at sunset. Let's remember >> > first >> > > > that the Perseids aren't really coming from Perseus but from a >> stream >> > of >> > > > dust through which Earth passes. The dust doesn't rotate as Earth >> > does. >> > > > Then do this thought experiment: pretend you're a meteor that's >> going >> > to >> > > > flash into our atmosphere from the direction of the North Star and >> > cross >> > > > the whole sky. If you do that in the middle of the night you cross a >> > > > certain number of constellations that are up at that time. But if >> you >> > > > decide to zoom in 12 hours later, during the day, you will cross an >> > > > entirely different set of (unseen to Earthlings) constellations. The >> > > entry >> > > > point was the same place and the angle of entry was the same but the >> > > > trajectory crossed entirely different locations. If you vary that by >> > an >> > > > hour instead of half a day you still >> > > > get a different track. A galaxy rotates as it crosses the sky just >> the >> > > way >> > > > the moon does. I got my planetarium program going and I put the edge >> > of >> > > a >> > > > piece of paper from NGC6946 to Perseus. Then I advanced the time by >> > > half an >> > > > hour. The galaxy rotated considerably in that time while I kept the >> > > paper >> > > > pointed at Perseus. In half an hour the direction that the Perseid >> > > meteors >> > > > streak across the galaxy changes. -- Joe >> > > > >> > > > >> > > > >> > > > ________________________________ >> > > > From: Brent Watson <brentjwatson(a)yahoo.com> >> > > > To: Utah Astronomy <utah-astronomy(a)mailman.xmission.com> >> > > > Sent: Friday, August 16, 2013 9:31 PM >> > > > Subject: Re: [Utah-astronomy] Galaxy NGC 6946 through smoke and >> > > meteriors >> > > > >> > > > >> > > > Joe, >> > > > >> > > > The whole sky rotates at the same rate. It rotates very close to 1 >> > hour >> > > > of right ascension per hour of mean solar time, as measured by your >> > > watch. >> > > > The angle between the radiant and the galaxy will not change, >> > > neglecting >> > > > the movement of the radiant itself. (That movement happens over >> days, >> > > not >> > > > minutes.) Both of those traces cannot be due to Perseid meteors >> > > because of >> > > > the angle formed by the two traces. One of them MAY be, but the >> other >> > > is >> > > > certainly not. How does the the line from the radiant intersect NGC >> > > 6946 >> > > > as seen on your digital planetarium? Does it pass through at the >> same >> > > > angle as one of the traces? If not, then both are either sporadic >> or >> > > not >> > > > meteors at all. >> > > > >> > > > Brent >> > > > >> > > > >> > > > ________________________________ >> > > > From: Joe Bauman <josephmbauman(a)yahoo.com> >> > > > To: Utah Astronomy <utah-astronomy(a)mailman.xmission.com> >> > > > Sent: Friday, August 16, 2013 6:09 PM >> > > > Subject: Re: [Utah-astronomy] Galaxy NGC 6946 through smoke and >> > > meteriors >> > > > >> > > > >> > > > Looking at my computerized planetarium, it's certainly possible to >> > draw >> > > a >> > > > radiant from Perseus to NGC 6946 at the time I took the views, about >> > > 3:14 >> > > > and 3:44 a.m., respectively, on Wednesday morning. I haven't had >> time >> > to >> > > > figure it out formally yet, but by running my planetarium program >> from >> > > the >> > > > first to the second time it looks like NGC 6946 revolves about the >> > same >> > > > amount as the difference in the lines in the two subs. Because they >> > are >> > > in >> > > > different sections of the sky, the galaxy and the constellation >> > revolve >> > > at >> > > > different rates. So unless someone wants to be a lot more scientific >> > > about >> > > > calculating >> > > > these things and proves me wrong, I will continue to believe they >> are >> > > both >> > > > Perseids. -- Joe >> > > > >> > > > >> > > > >> > > > >> > > > ________________________________ >> > > > From: Chuck Hards <chuck.hards(a)gmail.com> >> > > > To: Utah Astronomy <utah-astronomy(a)mailman.xmission.com> >> > > > Sent: Friday, August 16, 2013 4:40 PM >> > > > Subject: Re: [Utah-astronomy] Galaxy NGC 6946 through smoke and >> > > meteriors >> > > > >> > > > >> > > > For the meteors to be considered Perseids, they must have radiated >> > from >> > > the >> > > > Perseid radiant. They can appear anywhere in the sky, and at any >> > angle >> > > > relative to the observer, but in order to be a member of a given >> > > shower, if >> > > > you extend their path backwards across the sky, it must intersect >> the >> > > > radiant. If it doesn't, it's a sporadic, or a member of a different >> > > > shower. Some showers do overlap their times of activity. >> > > > >> > > > All members of a given shower hit the earth's atmosphere at the same >> > > > angle. They are traveling parallel in space. It just looks >> different >> > > to a >> > > > ground-based observer. >> > > > >> > > > Imagine the radiant as a sort of "vanishing point" in the sky. >> > > > >> > > > On Fri, Aug 16, 2013 at 2:25 PM, Joe Bauman < >> josephmbauman(a)yahoo.com> >> > > > wrote: >> > > > >> > > > > >> > > > > >> > > > > >> > > > > I did consult a star atlas ant I think they could be perseids -- >> > > > > meteorites seem to show up at various parts of the sky, not >> > > necessarily >> > > > > heading from Perseus directly. It is a wide stream of cometary >> dust >> > > that >> > > > > yge Earth passes through and I reckon that the atmosphere may hit >> > the >> > > > dust >> > > > > grains at various angles. Also saying the tracks look too uniform >> > > isn't a >> > > > > good way to judge them when you consider the field of view is tiny >> > -- >> > > in >> > > > a >> > > > > larger field they may have been less regular over s lmgrt stretch >> of >> > > > their >> > > > > entry path. Well, that's my story and I'm stickin' with if! -- >> > Thanks, >> > > > Joe >> > > > > >> > > > > ------------------------------ >> > > > > On Fri, Aug 16, 2013 9:48 AM MDT Brent Watson wrote: >> > > > > >> > > > > >Joe, >> > > > > > >> > > > > >They can't both be Perseids. They are coming from different >> > > directions. >> > > > > I am not sure where the Perseid radiant is with respect to your >> > > > > photograph, but in fact neither may be a Perseid. Please check >> the >> > > > > direction of travel. The tracks also look pretty uniform. In >> fact, >> > > > almost >> > > > > too uniform to be meteors. Are they instead, satellites? >> > > > > > >> > > > > >> > > > _______________________________________________ >> > > > Utah-Astronomy mailing list >> > > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > > > >> > > > Send messages to the list to >> > > > Utah-Astronomy(a)mailman.xmission.com >> > > > >> > > > The Utah-Astronomy mailing list is not affiliated with any astronomy >> > > club. >> > > > >> > > > To unsubscribe go to: >> > > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > > > Then enter your email address in the space provided and click on >> > > > "Unsubscribe or edit options". >> > > > _______________________________________________ >> > > > Utah-Astronomy mailing list >> > > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > > > >> > > > Send messages to the list to >> > > > Utah-Astronomy(a)mailman.xmission.com >> > > > >> > > > The Utah-Astronomy mailing list is not affiliated with any astronomy >> > > club. >> > > > >> > > > To unsubscribe go to: >> > > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > > > Then enter your email address in the space provided and click on >> > > > "Unsubscribe or edit options". >> > > > _______________________________________________ >> > > > Utah-Astronomy mailing list >> > > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > > > >> > > > Send messages to the list to >> > > > Utah-Astronomy(a)mailman.xmission.com >> > > > >> > > > The Utah-Astronomy mailing list is not affiliated with any astronomy >> > > club. >> > > > >> > > > To unsubscribe go to: >> > > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > > > Then enter your email address in the space provided and click on >> > > > "Unsubscribe or edit options". >> > > > _______________________________________________ >> > > > Utah-Astronomy mailing list >> > > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > > > >> > > > Send messages to the list to >> > > > Utah-Astronomy(a)mailman.xmission.com >> > > > >> > > > The Utah-Astronomy mailing list is not affiliated with any astronomy >> > > club. >> > > > >> > > > To unsubscribe go to: >> > > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > > > Then enter your email address in the space provided and click on >> > > > "Unsubscribe or edit options". >> > > > _______________________________________________ >> > > > Utah-Astronomy mailing list >> > > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > > > >> > > > Send messages to the list to >> > > > Utah-Astronomy(a)mailman.xmission.com >> > > > >> > > > The Utah-Astronomy mailing list is not affiliated with any astronomy >> > > club. >> > > > >> > > > To unsubscribe go to: >> > > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > > > Then enter your email address in the space provided and click on >> > > > "Unsubscribe or edit options". >> > > > >> > > >_______________________________________________ >> > > >Utah-Astronomy mailing list >> > > >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > > > >> > > >Send messages to the list to >> > > >Utah-Astronomy(a)mailman.xmission.com >> > > > >> > > >The Utah-Astronomy mailing list is not affiliated with any astronomy >> > club. >> > > > >> > > >To unsubscribe go to: >> > > >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > > >Then enter your email address in the space provided and click on >> > > "Unsubscribe or edit options". >> > > >> > > >> > > _______________________________________________ >> > > Utah-Astronomy mailing list >> > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > > >> > > Send messages to the list to >> > > Utah-Astronomy(a)mailman.xmission.com >> > > >> > > The Utah-Astronomy mailing list is not affiliated with any astronomy >> > club. >> > > >> > > To unsubscribe go to: >> > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > > Then enter your email address in the space provided and click on >> > > "Unsubscribe or edit options". >> > > >> > >_______________________________________________ >> > >Utah-Astronomy mailing list >> > >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > > >> > >Send messages to the list to >> > >Utah-Astronomy(a)mailman.xmission.com >> > > >> > >The Utah-Astronomy mailing list is not affiliated with any astronomy >> club. >> > > >> > >To unsubscribe go to: >> > >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > >Then enter your email address in the space provided and click on >> > "Unsubscribe or edit options". >> > >> > >> > _______________________________________________ >> > Utah-Astronomy mailing list >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > >> > Send messages to the list to >> > Utah-Astronomy(a)mailman.xmission.com >> > >> > The Utah-Astronomy mailing list is not affiliated with any astronomy >> club. >> > >> > To unsubscribe go to: >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > Then enter your email address in the space provided and click on >> > "Unsubscribe or edit options". >> > >> >_______________________________________________ >> >Utah-Astronomy mailing list >> >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > >> >Send messages to the list to >> >Utah-Astronomy(a)mailman.xmission.com >> > >> >The Utah-Astronomy mailing list is not affiliated with any astronomy club. >> > >> >To unsubscribe go to: >> >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> >Then enter your email address in the space provided and click on >> "Unsubscribe or edit options". >> >> >> _______________________________________________ >> Utah-Astronomy mailing list >> http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> >> Send messages to the list to >> Utah-Astronomy(a)mailman.xmission.com >> >> The Utah-Astronomy mailing list is not affiliated with any astronomy club. >> >> To unsubscribe go to: >> http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> Then enter your email address in the space provided and click on >> "Unsubscribe or edit options". >> >_______________________________________________ >Utah-Astronomy mailing list >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy > >Send messages to the list to >Utah-Astronomy(a)mailman.xmission.com > >The Utah-Astronomy mailing list is not affiliated with any astronomy club. > >To unsubscribe go to: >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >Then enter your email address in the space provided and click on "Unsubscribe or edit options".

5 5

Re: [Utah-astronomy] Galaxy NGC 6946 through smoke and meteriors
by Joe Bauman 17 Aug '13

17 Aug '13

No, the radiant does change because it comes from an essentially unmoving stream of dust particles in space generally toward the northeast. As Earn rotates relative yo this stream different sections of the atmosphere impact it. The stream is a physical trail that the Earth bumps against as Earth turns. ------------------------------ On Sat, Aug 17, 2013 3:46 PM MDT Chuck Hards wrote: >What you are forgetting, Joe, is that the radiant is rotating with the sky >as well. The relationship between the target galaxy and the radiant >doesn't change. > On Aug 17, 2013 3:19 PM, "Joe Bauman" <josephmbauman(a)yahoo.com> wrote: > >> >> >> Field rotation is relative to the observer on Earth -- true. But the >> tracking telescope compensates for it, meaning that the view in the camera >> actually rotates as the camera does. A shot fired across the view from the >> northeast part of the sky -- the trail of a Perseid metetor -- will cut >> across the frame at one direction. When the camera has rotated for half an >> hour a shot from the same northeastern section would seem to cross the >> frame at a different angle. The stream of dust is still coming from the >> northeast but the galaxy has rotated a certain amount relative to it. The >> distance of the target from the North Star will dictate how much difference >> there is. -- Joe >> >> >> ------------------------------ >> On Sat, Aug 17, 2013 2:33 PM MDT Chuck Hards wrote: >> >> >But they do not rotate relative to the RA/DEC coordinate grid, which is >> the >> >crux of this discussion. Field rotation, which is rotation relative to an >> >observer on earth, has nothing to do with it. You keep invoking it Joe, >> >and It's really outside the matter of determining if a meteor is a Perseid >> >or not. >> > >> >Brent is correct. >> >On Aug 17, 2013 2:23 PM, "Joe Bauman" <josephmbauman(a)yahoo.com> wrote: >> > >> > >> > Right, but celectial objects do rotate relative to that line. -- Joe >> > >> > >> > >> > ------------------------------ >> > On Sat, Aug 17, 2013 10:15 AM MDT Chuck Hards wrote: >> > >> > >Brent, I think Joe is just having trouble with polar coordinates. >> > >Joe, a straight line on the sky will always project as a curve on a >> > >2-dimensional computer screen, unless extremely short. >> > > On Aug 17, 2013 9:23 AM, "Brent Watson" <brentjwatson(a)yahoo.com> >> wrote: >> > > >> > > Joe, >> > > >> > > I think we have to agree to disagree. A perseid can never come from >> the >> > > North Star. Likewise, north in your photo will always be north, and >> the >> > > direction the galaxy is facing relative to celestial north will not >> > change. >> > > Your exercise of putting a piece of paper on your screen is not >> valid >> > > either. I am at a loss to be able to explain this unless we sit down >> > > together and use some visual aids, so lets agree to disagree. >> > > >> > > Brent >> > > >> > > >> > > ________________________________ >> > > From: Joe Bauman <josephmbauman(a)yahoo.com> >> > > To: Utah Astronomy <utah-astronomy(a)mailman.xmission.com> >> > > Sent: Friday, August 16, 2013 11:38 PM >> > > Subject: Re: [Utah-astronomy] Galaxy NGC 6946 through smoke and >> > meteriors >> > > >> > > >> > > That's just not entirely true, Brent. The galaxy itself appears to >> > rotate >> > > as the night progresses, even minute by minute, just as the moon ends >> > > upside down at sunrise from what it was at sunset. Let's remember >> first >> > > that the Perseids aren't really coming from Perseus but from a stream >> of >> > > dust through which Earth passes. The dust doesn't rotate as Earth >> does. >> > > Then do this thought experiment: pretend you're a meteor that's going >> to >> > > flash into our atmosphere from the direction of the North Star and >> cross >> > > the whole sky. If you do that in the middle of the night you cross a >> > > certain number of constellations that are up at that time. But if you >> > > decide to zoom in 12 hours later, during the day, you will cross an >> > > entirely different set of (unseen to Earthlings) constellations. The >> > entry >> > > point was the same place and the angle of entry was the same but the >> > > trajectory crossed entirely different locations. If you vary that by >> an >> > > hour instead of half a day you still >> > > get a different track. A galaxy rotates as it crosses the sky just the >> > way >> > > the moon does. I got my planetarium program going and I put the edge >> of >> > a >> > > piece of paper from NGC6946 to Perseus. Then I advanced the time by >> > half an >> > > hour. The galaxy rotated considerably in that time while I kept the >> > paper >> > > pointed at Perseus. In half an hour the direction that the Perseid >> > meteors >> > > streak across the galaxy changes. -- Joe >> > > >> > > >> > > >> > > ________________________________ >> > > From: Brent Watson <brentjwatson(a)yahoo.com> >> > > To: Utah Astronomy <utah-astronomy(a)mailman.xmission.com> >> > > Sent: Friday, August 16, 2013 9:31 PM >> > > Subject: Re: [Utah-astronomy] Galaxy NGC 6946 through smoke and >> > meteriors >> > > >> > > >> > > Joe, >> > > >> > > The whole sky rotates at the same rate. It rotates very close to 1 >> hour >> > > of right ascension per hour of mean solar time, as measured by your >> > watch. >> > > The angle between the radiant and the galaxy will not change, >> > neglecting >> > > the movement of the radiant itself. (That movement happens over days, >> > not >> > > minutes.) Both of those traces cannot be due to Perseid meteors >> > because of >> > > the angle formed by the two traces. One of them MAY be, but the other >> > is >> > > certainly not. How does the the line from the radiant intersect NGC >> > 6946 >> > > as seen on your digital planetarium? Does it pass through at the same >> > > angle as one of the traces? If not, then both are either sporadic or >> > not >> > > meteors at all. >> > > >> > > Brent >> > > >> > > >> > > ________________________________ >> > > From: Joe Bauman <josephmbauman(a)yahoo.com> >> > > To: Utah Astronomy <utah-astronomy(a)mailman.xmission.com> >> > > Sent: Friday, August 16, 2013 6:09 PM >> > > Subject: Re: [Utah-astronomy] Galaxy NGC 6946 through smoke and >> > meteriors >> > > >> > > >> > > Looking at my computerized planetarium, it's certainly possible to >> draw >> > a >> > > radiant from Perseus to NGC 6946 at the time I took the views, about >> > 3:14 >> > > and 3:44 a.m., respectively, on Wednesday morning. I haven't had time >> to >> > > figure it out formally yet, but by running my planetarium program from >> > the >> > > first to the second time it looks like NGC 6946 revolves about the >> same >> > > amount as the difference in the lines in the two subs. Because they >> are >> > in >> > > different sections of the sky, the galaxy and the constellation >> revolve >> > at >> > > different rates. So unless someone wants to be a lot more scientific >> > about >> > > calculating >> > > these things and proves me wrong, I will continue to believe they are >> > both >> > > Perseids. -- Joe >> > > >> > > >> > > >> > > >> > > ________________________________ >> > > From: Chuck Hards <chuck.hards(a)gmail.com> >> > > To: Utah Astronomy <utah-astronomy(a)mailman.xmission.com> >> > > Sent: Friday, August 16, 2013 4:40 PM >> > > Subject: Re: [Utah-astronomy] Galaxy NGC 6946 through smoke and >> > meteriors >> > > >> > > >> > > For the meteors to be considered Perseids, they must have radiated >> from >> > the >> > > Perseid radiant. They can appear anywhere in the sky, and at any >> angle >> > > relative to the observer, but in order to be a member of a given >> > shower, if >> > > you extend their path backwards across the sky, it must intersect the >> > > radiant. If it doesn't, it's a sporadic, or a member of a different >> > > shower. Some showers do overlap their times of activity. >> > > >> > > All members of a given shower hit the earth's atmosphere at the same >> > > angle. They are traveling parallel in space. It just looks different >> > to a >> > > ground-based observer. >> > > >> > > Imagine the radiant as a sort of "vanishing point" in the sky. >> > > >> > > On Fri, Aug 16, 2013 at 2:25 PM, Joe Bauman <josephmbauman(a)yahoo.com> >> > > wrote: >> > > >> > > > >> > > > >> > > > >> > > > I did consult a star atlas ant I think they could be perseids -- >> > > > meteorites seem to show up at various parts of the sky, not >> > necessarily >> > > > heading from Perseus directly. It is a wide stream of cometary dust >> > that >> > > > yge Earth passes through and I reckon that the atmosphere may hit >> the >> > > dust >> > > > grains at various angles. Also saying the tracks look too uniform >> > isn't a >> > > > good way to judge them when you consider the field of view is tiny >> -- >> > in >> > > a >> > > > larger field they may have been less regular over s lmgrt stretch of >> > > their >> > > > entry path. Well, that's my story and I'm stickin' with if! -- >> Thanks, >> > > Joe >> > > > >> > > > ------------------------------ >> > > > On Fri, Aug 16, 2013 9:48 AM MDT Brent Watson wrote: >> > > > >> > > > >Joe, >> > > > > >> > > > >They can't both be Perseids. They are coming from different >> > directions. >> > > > I am not sure where the Perseid radiant is with respect to your >> > > > photograph, but in fact neither may be a Perseid. Please check the >> > > > direction of travel. The tracks also look pretty uniform. In fact, >> > > almost >> > > > too uniform to be meteors. Are they instead, satellites? >> > > > > >> > > > >> > > _______________________________________________ >> > > Utah-Astronomy mailing list >> > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > > >> > > Send messages to the list to >> > > Utah-Astronomy(a)mailman.xmission.com >> > > >> > > The Utah-Astronomy mailing list is not affiliated with any astronomy >> > club. >> > > >> > > To unsubscribe go to: >> > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > > Then enter your email address in the space provided and click on >> > > "Unsubscribe or edit options". >> > > _______________________________________________ >> > > Utah-Astronomy mailing list >> > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > > >> > > Send messages to the list to >> > > Utah-Astronomy(a)mailman.xmission.com >> > > >> > > The Utah-Astronomy mailing list is not affiliated with any astronomy >> > club. >> > > >> > > To unsubscribe go to: >> > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > > Then enter your email address in the space provided and click on >> > > "Unsubscribe or edit options". >> > > _______________________________________________ >> > > Utah-Astronomy mailing list >> > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > > >> > > Send messages to the list to >> > > Utah-Astronomy(a)mailman.xmission.com >> > > >> > > The Utah-Astronomy mailing list is not affiliated with any astronomy >> > club. >> > > >> > > To unsubscribe go to: >> > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > > Then enter your email address in the space provided and click on >> > > "Unsubscribe or edit options". >> > > _______________________________________________ >> > > Utah-Astronomy mailing list >> > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > > >> > > Send messages to the list to >> > > Utah-Astronomy(a)mailman.xmission.com >> > > >> > > The Utah-Astronomy mailing list is not affiliated with any astronomy >> > club. >> > > >> > > To unsubscribe go to: >> > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > > Then enter your email address in the space provided and click on >> > > "Unsubscribe or edit options". >> > > _______________________________________________ >> > > Utah-Astronomy mailing list >> > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > > >> > > Send messages to the list to >> > > Utah-Astronomy(a)mailman.xmission.com >> > > >> > > The Utah-Astronomy mailing list is not affiliated with any astronomy >> > club. >> > > >> > > To unsubscribe go to: >> > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > > Then enter your email address in the space provided and click on >> > > "Unsubscribe or edit options". >> > > >> > >_______________________________________________ >> > >Utah-Astronomy mailing list >> > >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > > >> > >Send messages to the list to >> > >Utah-Astronomy(a)mailman.xmission.com >> > > >> > >The Utah-Astronomy mailing list is not affiliated with any astronomy >> club. >> > > >> > >To unsubscribe go to: >> > >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > >Then enter your email address in the space provided and click on >> > "Unsubscribe or edit options". >> > >> > >> > _______________________________________________ >> > Utah-Astronomy mailing list >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > >> > Send messages to the list to >> > Utah-Astronomy(a)mailman.xmission.com >> > >> > The Utah-Astronomy mailing list is not affiliated with any astronomy >> club. >> > >> > To unsubscribe go to: >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > Then enter your email address in the space provided and click on >> > "Unsubscribe or edit options". >> > >> >_______________________________________________ >> >Utah-Astronomy mailing list >> >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > >> >Send messages to the list to >> >Utah-Astronomy(a)mailman.xmission.com >> > >> >The Utah-Astronomy mailing list is not affiliated with any astronomy club. >> > >> >To unsubscribe go to: >> >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> >Then enter your email address in the space provided and click on >> "Unsubscribe or edit options". >> >> >> _______________________________________________ >> Utah-Astronomy mailing list >> http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> >> Send messages to the list to >> Utah-Astronomy(a)mailman.xmission.com >> >> The Utah-Astronomy mailing list is not affiliated with any astronomy club. >> >> To unsubscribe go to: >> http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> Then enter your email address in the space provided and click on >> "Unsubscribe or edit options". >> >_______________________________________________ >Utah-Astronomy mailing list >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy > >Send messages to the list to >Utah-Astronomy(a)mailman.xmission.com > >The Utah-Astronomy mailing list is not affiliated with any astronomy club. > >To unsubscribe go to: >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >Then enter your email address in the space provided and click on "Unsubscribe or edit options".

2 1

Re: [Utah-astronomy] Galaxy NGC 6946 through smoke and meteriors
by Joe Bauman 17 Aug '13

17 Aug '13

Field rotation is relative to the observer on Earth -- true. But the tracking telescope compensates for it, meaning that the view in the camera actually rotates as the camera does. A shot fired across the view from the northeast part of the sky -- the trail of a Perseid metetor -- will cut across the frame at one direction. When the camera has rotated for half an hour a shot from the same northeastern section would seem to cross the frame at a different angle. The stream of dust is still coming from the northeast but the galaxy has rotated a certain amount relative to it. The distance of the target from the North Star will dictate how much difference there is. -- Joe ------------------------------ On Sat, Aug 17, 2013 2:33 PM MDT Chuck Hards wrote: >But they do not rotate relative to the RA/DEC coordinate grid, which is the >crux of this discussion. Field rotation, which is rotation relative to an >observer on earth, has nothing to do with it. You keep invoking it Joe, >and It's really outside the matter of determining if a meteor is a Perseid >or not. > >Brent is correct. >On Aug 17, 2013 2:23 PM, "Joe Bauman" <josephmbauman(a)yahoo.com> wrote: > >> >> Right, but celectial objects do rotate relative to that line. -- Joe >> >> >> >> ------------------------------ >> On Sat, Aug 17, 2013 10:15 AM MDT Chuck Hards wrote: >> >> >Brent, I think Joe is just having trouble with polar coordinates. >> >Joe, a straight line on the sky will always project as a curve on a >> >2-dimensional computer screen, unless extremely short. >> > On Aug 17, 2013 9:23 AM, "Brent Watson" <brentjwatson(a)yahoo.com> wrote: >> > >> > Joe, >> > >> > I think we have to agree to disagree. A perseid can never come from the >> > North Star. Likewise, north in your photo will always be north, and the >> > direction the galaxy is facing relative to celestial north will not >> change. >> > Your exercise of putting a piece of paper on your screen is not valid >> > either. I am at a loss to be able to explain this unless we sit down >> > together and use some visual aids, so lets agree to disagree. >> > >> > Brent >> > >> > >> > ________________________________ >> > From: Joe Bauman <josephmbauman(a)yahoo.com> >> > To: Utah Astronomy <utah-astronomy(a)mailman.xmission.com> >> > Sent: Friday, August 16, 2013 11:38 PM >> > Subject: Re: [Utah-astronomy] Galaxy NGC 6946 through smoke and >> meteriors >> > >> > >> > That's just not entirely true, Brent. The galaxy itself appears to >> rotate >> > as the night progresses, even minute by minute, just as the moon ends >> > upside down at sunrise from what it was at sunset. Let's remember first >> > that the Perseids aren't really coming from Perseus but from a stream of >> > dust through which Earth passes. The dust doesn't rotate as Earth does. >> > Then do this thought experiment: pretend you're a meteor that's going to >> > flash into our atmosphere from the direction of the North Star and cross >> > the whole sky. If you do that in the middle of the night you cross a >> > certain number of constellations that are up at that time. But if you >> > decide to zoom in 12 hours later, during the day, you will cross an >> > entirely different set of (unseen to Earthlings) constellations. The >> entry >> > point was the same place and the angle of entry was the same but the >> > trajectory crossed entirely different locations. If you vary that by an >> > hour instead of half a day you still >> > get a different track. A galaxy rotates as it crosses the sky just the >> way >> > the moon does. I got my planetarium program going and I put the edge of >> a >> > piece of paper from NGC6946 to Perseus. Then I advanced the time by >> half an >> > hour. The galaxy rotated considerably in that time while I kept the >> paper >> > pointed at Perseus. In half an hour the direction that the Perseid >> meteors >> > streak across the galaxy changes. -- Joe >> > >> > >> > >> > ________________________________ >> > From: Brent Watson <brentjwatson(a)yahoo.com> >> > To: Utah Astronomy <utah-astronomy(a)mailman.xmission.com> >> > Sent: Friday, August 16, 2013 9:31 PM >> > Subject: Re: [Utah-astronomy] Galaxy NGC 6946 through smoke and >> meteriors >> > >> > >> > Joe, >> > >> > The whole sky rotates at the same rate. It rotates very close to 1 hour >> > of right ascension per hour of mean solar time, as measured by your >> watch. >> > The angle between the radiant and the galaxy will not change, >> neglecting >> > the movement of the radiant itself. (That movement happens over days, >> not >> > minutes.) Both of those traces cannot be due to Perseid meteors >> because of >> > the angle formed by the two traces. One of them MAY be, but the other >> is >> > certainly not. How does the the line from the radiant intersect NGC >> 6946 >> > as seen on your digital planetarium? Does it pass through at the same >> > angle as one of the traces? If not, then both are either sporadic or >> not >> > meteors at all. >> > >> > Brent >> > >> > >> > ________________________________ >> > From: Joe Bauman <josephmbauman(a)yahoo.com> >> > To: Utah Astronomy <utah-astronomy(a)mailman.xmission.com> >> > Sent: Friday, August 16, 2013 6:09 PM >> > Subject: Re: [Utah-astronomy] Galaxy NGC 6946 through smoke and >> meteriors >> > >> > >> > Looking at my computerized planetarium, it's certainly possible to draw >> a >> > radiant from Perseus to NGC 6946 at the time I took the views, about >> 3:14 >> > and 3:44 a.m., respectively, on Wednesday morning. I haven't had time to >> > figure it out formally yet, but by running my planetarium program from >> the >> > first to the second time it looks like NGC 6946 revolves about the same >> > amount as the difference in the lines in the two subs. Because they are >> in >> > different sections of the sky, the galaxy and the constellation revolve >> at >> > different rates. So unless someone wants to be a lot more scientific >> about >> > calculating >> > these things and proves me wrong, I will continue to believe they are >> both >> > Perseids. -- Joe >> > >> > >> > >> > >> > ________________________________ >> > From: Chuck Hards <chuck.hards(a)gmail.com> >> > To: Utah Astronomy <utah-astronomy(a)mailman.xmission.com> >> > Sent: Friday, August 16, 2013 4:40 PM >> > Subject: Re: [Utah-astronomy] Galaxy NGC 6946 through smoke and >> meteriors >> > >> > >> > For the meteors to be considered Perseids, they must have radiated from >> the >> > Perseid radiant. They can appear anywhere in the sky, and at any angle >> > relative to the observer, but in order to be a member of a given >> shower, if >> > you extend their path backwards across the sky, it must intersect the >> > radiant. If it doesn't, it's a sporadic, or a member of a different >> > shower. Some showers do overlap their times of activity. >> > >> > All members of a given shower hit the earth's atmosphere at the same >> > angle. They are traveling parallel in space. It just looks different >> to a >> > ground-based observer. >> > >> > Imagine the radiant as a sort of "vanishing point" in the sky. >> > >> > On Fri, Aug 16, 2013 at 2:25 PM, Joe Bauman <josephmbauman(a)yahoo.com> >> > wrote: >> > >> > > >> > > >> > > >> > > I did consult a star atlas ant I think they could be perseids -- >> > > meteorites seem to show up at various parts of the sky, not >> necessarily >> > > heading from Perseus directly. It is a wide stream of cometary dust >> that >> > > yge Earth passes through and I reckon that the atmosphere may hit the >> > dust >> > > grains at various angles. Also saying the tracks look too uniform >> isn't a >> > > good way to judge them when you consider the field of view is tiny -- >> in >> > a >> > > larger field they may have been less regular over s lmgrt stretch of >> > their >> > > entry path. Well, that's my story and I'm stickin' with if! -- Thanks, >> > Joe >> > > >> > > ------------------------------ >> > > On Fri, Aug 16, 2013 9:48 AM MDT Brent Watson wrote: >> > > >> > > >Joe, >> > > > >> > > >They can't both be Perseids. They are coming from different >> directions. >> > > I am not sure where the Perseid radiant is with respect to your >> > > photograph, but in fact neither may be a Perseid. Please check the >> > > direction of travel. The tracks also look pretty uniform. In fact, >> > almost >> > > too uniform to be meteors. Are they instead, satellites? >> > > > >> > > >> > _______________________________________________ >> > Utah-Astronomy mailing list >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > >> > Send messages to the list to >> > Utah-Astronomy(a)mailman.xmission.com >> > >> > The Utah-Astronomy mailing list is not affiliated with any astronomy >> club. >> > >> > To unsubscribe go to: >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > Then enter your email address in the space provided and click on >> > "Unsubscribe or edit options". >> > _______________________________________________ >> > Utah-Astronomy mailing list >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > >> > Send messages to the list to >> > Utah-Astronomy(a)mailman.xmission.com >> > >> > The Utah-Astronomy mailing list is not affiliated with any astronomy >> club. >> > >> > To unsubscribe go to: >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > Then enter your email address in the space provided and click on >> > "Unsubscribe or edit options". >> > _______________________________________________ >> > Utah-Astronomy mailing list >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > >> > Send messages to the list to >> > Utah-Astronomy(a)mailman.xmission.com >> > >> > The Utah-Astronomy mailing list is not affiliated with any astronomy >> club. >> > >> > To unsubscribe go to: >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > Then enter your email address in the space provided and click on >> > "Unsubscribe or edit options". >> > _______________________________________________ >> > Utah-Astronomy mailing list >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > >> > Send messages to the list to >> > Utah-Astronomy(a)mailman.xmission.com >> > >> > The Utah-Astronomy mailing list is not affiliated with any astronomy >> club. >> > >> > To unsubscribe go to: >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > Then enter your email address in the space provided and click on >> > "Unsubscribe or edit options". >> > _______________________________________________ >> > Utah-Astronomy mailing list >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > >> > Send messages to the list to >> > Utah-Astronomy(a)mailman.xmission.com >> > >> > The Utah-Astronomy mailing list is not affiliated with any astronomy >> club. >> > >> > To unsubscribe go to: >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > Then enter your email address in the space provided and click on >> > "Unsubscribe or edit options". >> > >> >_______________________________________________ >> >Utah-Astronomy mailing list >> >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > >> >Send messages to the list to >> >Utah-Astronomy(a)mailman.xmission.com >> > >> >The Utah-Astronomy mailing list is not affiliated with any astronomy club. >> > >> >To unsubscribe go to: >> >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> >Then enter your email address in the space provided and click on >> "Unsubscribe or edit options". >> >> >> _______________________________________________ >> Utah-Astronomy mailing list >> http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> >> Send messages to the list to >> Utah-Astronomy(a)mailman.xmission.com >> >> The Utah-Astronomy mailing list is not affiliated with any astronomy club. >> >> To unsubscribe go to: >> http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> Then enter your email address in the space provided and click on >> "Unsubscribe or edit options". >> >_______________________________________________ >Utah-Astronomy mailing list >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy > >Send messages to the list to >Utah-Astronomy(a)mailman.xmission.com > >The Utah-Astronomy mailing list is not affiliated with any astronomy club. > >To unsubscribe go to: >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >Then enter your email address in the space provided and click on "Unsubscribe or edit options".

3 2

Re: [Utah-astronomy] Galaxy NGC 6946 through smoke and meteriors
by Joe Bauman 17 Aug '13

17 Aug '13

Field rotation is relative to the observer on Earth -- true. But the tracking telescope compensates for it, meaning that the view in the camera actually rotates as the camera does. A shot fired across the view from the northeast part of the sky -- the trail of a Perseid metetor -- will cut across the frame at one direction. When the camera has rotated for half an hour a shot from the same northeastern section would seem to cross the frame at a different angle. The stream of dust is still coming from the northeast but the galaxy has rotated a certain amount relative to it. The distance of the target from the North Star will dictate how much difference there is. -- Joe ------------------------------ On Sat, Aug 17, 2013 2:33 PM MDT Chuck Hards wrote: >But they do not rotate relative to the RA/DEC coordinate grid, which is the >crux of this discussion. Field rotation, which is rotation relative to an >observer on earth, has nothing to do with it. You keep invoking it Joe, >and It's really outside the matter of determining if a meteor is a Perseid >or not. > >Brent is correct. >On Aug 17, 2013 2:23 PM, "Joe Bauman" <josephmbauman(a)yahoo.com> wrote: > >> >> Right, but celectial objects do rotate relative to that line. -- Joe >> >> >> >> ------------------------------ >> On Sat, Aug 17, 2013 10:15 AM MDT Chuck Hards wrote: >> >> >Brent, I think Joe is just having trouble with polar coordinates. >> >Joe, a straight line on the sky will always project as a curve on a >> >2-dimensional computer screen, unless extremely short. >> > On Aug 17, 2013 9:23 AM, "Brent Watson" <brentjwatson(a)yahoo.com> wrote: >> > >> > Joe, >> > >> > I think we have to agree to disagree. A perseid can never come from the >> > North Star. Likewise, north in your photo will always be north, and the >> > direction the galaxy is facing relative to celestial north will not >> change. >> > Your exercise of putting a piece of paper on your screen is not valid >> > either. I am at a loss to be able to explain this unless we sit down >> > together and use some visual aids, so lets agree to disagree. >> > >> > Brent >> > >> > >> > ________________________________ >> > From: Joe Bauman <josephmbauman(a)yahoo.com> >> > To: Utah Astronomy <utah-astronomy(a)mailman.xmission.com> >> > Sent: Friday, August 16, 2013 11:38 PM >> > Subject: Re: [Utah-astronomy] Galaxy NGC 6946 through smoke and >> meteriors >> > >> > >> > That's just not entirely true, Brent. The galaxy itself appears to >> rotate >> > as the night progresses, even minute by minute, just as the moon ends >> > upside down at sunrise from what it was at sunset. Let's remember first >> > that the Perseids aren't really coming from Perseus but from a stream of >> > dust through which Earth passes. The dust doesn't rotate as Earth does. >> > Then do this thought experiment: pretend you're a meteor that's going to >> > flash into our atmosphere from the direction of the North Star and cross >> > the whole sky. If you do that in the middle of the night you cross a >> > certain number of constellations that are up at that time. But if you >> > decide to zoom in 12 hours later, during the day, you will cross an >> > entirely different set of (unseen to Earthlings) constellations. The >> entry >> > point was the same place and the angle of entry was the same but the >> > trajectory crossed entirely different locations. If you vary that by an >> > hour instead of half a day you still >> > get a different track. A galaxy rotates as it crosses the sky just the >> way >> > the moon does. I got my planetarium program going and I put the edge of >> a >> > piece of paper from NGC6946 to Perseus. Then I advanced the time by >> half an >> > hour. The galaxy rotated considerably in that time while I kept the >> paper >> > pointed at Perseus. In half an hour the direction that the Perseid >> meteors >> > streak across the galaxy changes. -- Joe >> > >> > >> > >> > ________________________________ >> > From: Brent Watson <brentjwatson(a)yahoo.com> >> > To: Utah Astronomy <utah-astronomy(a)mailman.xmission.com> >> > Sent: Friday, August 16, 2013 9:31 PM >> > Subject: Re: [Utah-astronomy] Galaxy NGC 6946 through smoke and >> meteriors >> > >> > >> > Joe, >> > >> > The whole sky rotates at the same rate. It rotates very close to 1 hour >> > of right ascension per hour of mean solar time, as measured by your >> watch. >> > The angle between the radiant and the galaxy will not change, >> neglecting >> > the movement of the radiant itself. (That movement happens over days, >> not >> > minutes.) Both of those traces cannot be due to Perseid meteors >> because of >> > the angle formed by the two traces. One of them MAY be, but the other >> is >> > certainly not. How does the the line from the radiant intersect NGC >> 6946 >> > as seen on your digital planetarium? Does it pass through at the same >> > angle as one of the traces? If not, then both are either sporadic or >> not >> > meteors at all. >> > >> > Brent >> > >> > >> > ________________________________ >> > From: Joe Bauman <josephmbauman(a)yahoo.com> >> > To: Utah Astronomy <utah-astronomy(a)mailman.xmission.com> >> > Sent: Friday, August 16, 2013 6:09 PM >> > Subject: Re: [Utah-astronomy] Galaxy NGC 6946 through smoke and >> meteriors >> > >> > >> > Looking at my computerized planetarium, it's certainly possible to draw >> a >> > radiant from Perseus to NGC 6946 at the time I took the views, about >> 3:14 >> > and 3:44 a.m., respectively, on Wednesday morning. I haven't had time to >> > figure it out formally yet, but by running my planetarium program from >> the >> > first to the second time it looks like NGC 6946 revolves about the same >> > amount as the difference in the lines in the two subs. Because they are >> in >> > different sections of the sky, the galaxy and the constellation revolve >> at >> > different rates. So unless someone wants to be a lot more scientific >> about >> > calculating >> > these things and proves me wrong, I will continue to believe they are >> both >> > Perseids. -- Joe >> > >> > >> > >> > >> > ________________________________ >> > From: Chuck Hards <chuck.hards(a)gmail.com> >> > To: Utah Astronomy <utah-astronomy(a)mailman.xmission.com> >> > Sent: Friday, August 16, 2013 4:40 PM >> > Subject: Re: [Utah-astronomy] Galaxy NGC 6946 through smoke and >> meteriors >> > >> > >> > For the meteors to be considered Perseids, they must have radiated from >> the >> > Perseid radiant. They can appear anywhere in the sky, and at any angle >> > relative to the observer, but in order to be a member of a given >> shower, if >> > you extend their path backwards across the sky, it must intersect the >> > radiant. If it doesn't, it's a sporadic, or a member of a different >> > shower. Some showers do overlap their times of activity. >> > >> > All members of a given shower hit the earth's atmosphere at the same >> > angle. They are traveling parallel in space. It just looks different >> to a >> > ground-based observer. >> > >> > Imagine the radiant as a sort of "vanishing point" in the sky. >> > >> > On Fri, Aug 16, 2013 at 2:25 PM, Joe Bauman <josephmbauman(a)yahoo.com> >> > wrote: >> > >> > > >> > > >> > > >> > > I did consult a star atlas ant I think they could be perseids -- >> > > meteorites seem to show up at various parts of the sky, not >> necessarily >> > > heading from Perseus directly. It is a wide stream of cometary dust >> that >> > > yge Earth passes through and I reckon that the atmosphere may hit the >> > dust >> > > grains at various angles. Also saying the tracks look too uniform >> isn't a >> > > good way to judge them when you consider the field of view is tiny -- >> in >> > a >> > > larger field they may have been less regular over s lmgrt stretch of >> > their >> > > entry path. Well, that's my story and I'm stickin' with if! -- Thanks, >> > Joe >> > > >> > > ------------------------------ >> > > On Fri, Aug 16, 2013 9:48 AM MDT Brent Watson wrote: >> > > >> > > >Joe, >> > > > >> > > >They can't both be Perseids. They are coming from different >> directions. >> > > I am not sure where the Perseid radiant is with respect to your >> > > photograph, but in fact neither may be a Perseid. Please check the >> > > direction of travel. The tracks also look pretty uniform. In fact, >> > almost >> > > too uniform to be meteors. Are they instead, satellites? >> > > > >> > > >> > _______________________________________________ >> > Utah-Astronomy mailing list >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > >> > Send messages to the list to >> > Utah-Astronomy(a)mailman.xmission.com >> > >> > The Utah-Astronomy mailing list is not affiliated with any astronomy >> club. >> > >> > To unsubscribe go to: >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > Then enter your email address in the space provided and click on >> > "Unsubscribe or edit options". >> > _______________________________________________ >> > Utah-Astronomy mailing list >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > >> > Send messages to the list to >> > Utah-Astronomy(a)mailman.xmission.com >> > >> > The Utah-Astronomy mailing list is not affiliated with any astronomy >> club. >> > >> > To unsubscribe go to: >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > Then enter your email address in the space provided and click on >> > "Unsubscribe or edit options". >> > _______________________________________________ >> > Utah-Astronomy mailing list >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > >> > Send messages to the list to >> > Utah-Astronomy(a)mailman.xmission.com >> > >> > The Utah-Astronomy mailing list is not affiliated with any astronomy >> club. >> > >> > To unsubscribe go to: >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > Then enter your email address in the space provided and click on >> > "Unsubscribe or edit options". >> > _______________________________________________ >> > Utah-Astronomy mailing list >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > >> > Send messages to the list to >> > Utah-Astronomy(a)mailman.xmission.com >> > >> > The Utah-Astronomy mailing list is not affiliated with any astronomy >> club. >> > >> > To unsubscribe go to: >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > Then enter your email address in the space provided and click on >> > "Unsubscribe or edit options". >> > _______________________________________________ >> > Utah-Astronomy mailing list >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > >> > Send messages to the list to >> > Utah-Astronomy(a)mailman.xmission.com >> > >> > The Utah-Astronomy mailing list is not affiliated with any astronomy >> club. >> > >> > To unsubscribe go to: >> > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > Then enter your email address in the space provided and click on >> > "Unsubscribe or edit options". >> > >> >_______________________________________________ >> >Utah-Astronomy mailing list >> >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> > >> >Send messages to the list to >> >Utah-Astronomy(a)mailman.xmission.com >> > >> >The Utah-Astronomy mailing list is not affiliated with any astronomy club. >> > >> >To unsubscribe go to: >> >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> >Then enter your email address in the space provided and click on >> "Unsubscribe or edit options". >> >> >> _______________________________________________ >> Utah-Astronomy mailing list >> http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> >> Send messages to the list to >> Utah-Astronomy(a)mailman.xmission.com >> >> The Utah-Astronomy mailing list is not affiliated with any astronomy club. >> >> To unsubscribe go to: >> http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >> Then enter your email address in the space provided and click on >> "Unsubscribe or edit options". >> >_______________________________________________ >Utah-Astronomy mailing list >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy > >Send messages to the list to >Utah-Astronomy(a)mailman.xmission.com > >The Utah-Astronomy mailing list is not affiliated with any astronomy club. > >To unsubscribe go to: >http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy >Then enter your email address in the space provided and click on "Unsubscribe or edit options".

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