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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 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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 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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

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".

1 0

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

17 Aug '13

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".

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Re: [Utah-astronomy] Patch Springs fire updated image
by Kelly Ricks 17 Aug '13

17 Aug '13

Nice shots Patrick! Just a heads up: the second one seems to load upside down. I was wondering if after setting your speed record (wow! and congrats), you were hyped up enough to try loop de loops in your plane...while simultaneously taking photos no less! ~Kelly ------------------------------ > > Message: 3 > Date: Sat, 17 Aug 2013 01:22:21 -0600 > From: Patrick Wiggins <paw(a)wirelessbeehive.com> > To: utah astronomy listserve utah astronomy > <utah-astronomy(a)mailman.xmission.com> > Subject: [Utah-astronomy] Patch Springs fire updated image > Message-ID: <C740A57D-8DF5-41D0-8548-104655A69D3F(a)wirelessbeehive.com> > Content-Type: text/plain; charset=us-ascii > > Skies in the Tooele Valley still smokey but improving. > > Suspecting the fire was getting smaller I flew out west yesterday and saw > that it is considerably smaller and less smokey than when I saw it > Wednesday. > > Here's how it looked from the south looking north on Wednesday: > http://users.wirelessbeehive.com/~paw/temp/patchsprings20130814.jpg > > And here it is yesterday from the north looking south: > http://users.wirelessbeehive.com/~paw/temp/patchsprings20130816.jpg > > The top of the smoke is still way up there. Before taking the picture I'd > made a jump at the Tooele airport where we got out at 13,000 feet above the > ground and we were still in it (on a side note, on that jump I set my > personal vertical speed record of 183 mph <before losing it and flying all > out of control> ) > > So, maybe if the rain holds off the skies will be ok for this evening's > Stansbury Days star party at SPOC. > > patrick > > > ------------------------------ > > _______________________________________________ > Utah-Astronomy mailing list > Utah-Astronomy(a)mailman.xmission.com > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy > Visit the Photo Gallery: http://www.slas.us/gallery2/main.php > > End of Utah-Astronomy Digest, Vol 126, Issue 76 > *********************************************** >

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

17 Aug '13

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? > >Brent > > >________________________________ > From: Joe Bauman <josephmbauman(a)yahoo.com> >To: Utah Astronomy <utah-astronomy(a)mailman.xmission.com> >Sent: Thursday, August 15, 2013 10:25 PM >Subject: [Utah-astronomy] Galaxy NGC 6946 through smoke and meteriors > > >Hi Gang, Here are shots I took at Lakeside early Wednesday morning; the captions explain them. > > >http://www.slas.us/gallery2/main.php?g2_itemId=5713&g2_imageViewsIndex=1 > >http://www.slas.us/gallery2/main.php?g2_itemId=5716&g2_imageViewsIndex=1 > >http://www.slas.us/gallery2/main.php?g2_itemId=5719&g2_imageViewsIndex=1 > >Almost nothing but a few bright stars showed up in the blue exposures, thanks to the Patch Springs air filter. > >-- Thanks for looking, Joe >_______________________________________________ >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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Watch a 10 story building maneuver, hover and land
by Patrick Wiggins 17 Aug '13

17 Aug '13

In the latest from SpaceX, they've got their "Grasshopper" maneuvering as well as the previously demonstrated hovering. http://www.spacex.com/news/2013/08/14/grasshopper-100m-lateral-divert-test My question is how long until they start flying people in their "cargo carrying" Falcon 9? Look close at the the payload section and see that it's got windows. Cargo don't need no stinkin' windows... :) patrick

3 4

Patch Springs fire updated image
by Patrick Wiggins 17 Aug '13

17 Aug '13

Skies in the Tooele Valley still smokey but improving. Suspecting the fire was getting smaller I flew out west yesterday and saw that it is considerably smaller and less smokey than when I saw it Wednesday. Here's how it looked from the south looking north on Wednesday: http://users.wirelessbeehive.com/~paw/temp/patchsprings20130814.jpg And here it is yesterday from the north looking south: http://users.wirelessbeehive.com/~paw/temp/patchsprings20130816.jpg The top of the smoke is still way up there. Before taking the picture I'd made a jump at the Tooele airport where we got out at 13,000 feet above the ground and we were still in it (on a side note, on that jump I set my personal vertical speed record of 183 mph <before losing it and flying all out of control> ) So, maybe if the rain holds off the skies will be ok for this evening's Stansbury Days star party at SPOC. patrick

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