March 2009 - Utah-Astronomy - mailman.xmission.com

Re: [Utah-astronomy] Surface Brightness
by Jim Gibson 30 Mar '09

30 Mar '09

Good point Chuck. It’s only an approximation anyway. The answer to the surface brightness question goes into another formula. The formula I plug the surface brightness into only gives an approximation of how long an exposure is needed, so it doesn’t have to be exact. Since my camera sees in rectangles I figure it will be good enough to get an idea. The math for computing the area in a rectangle is easier than using methods of calculus to figure the exact answer only then to be used as an approximation. Depending on the answer, I would use the information to plan a set of integrations that would equal or exceed the estimate anyway. I would like to know why my math was so far off, though. I know you are and have been real busy for months, so don’t worry about figuring that out. I would like to bring my grandkids to SPOC the night you are there, but I don’t know if I can work it out yet. Jim --- On Mon, 3/30/09, Chuck Hards <chuck.hards(a)gmail.com> wrote: From: Chuck Hards <chuck.hards(a)gmail.com> Subject: Re: [Utah-astronomy] Surface Brightness To: "Utah Astronomy" <utah-astronomy(a)mailman.xmission.com> Date: Monday, March 30, 2009, 1:20 PM Jim, I haven't the time to run all the numbers right now, but I can tell you now that M1 isn't a rectangle. On Mon, Mar 30, 2009 at 9:31 AM, Jim Gibson <jimgibson00(a)yahoo.com> wrote: > I Need help from some of you math wiz-bangs. I looked up on a chart of > surface brightness that M1 has a surface brightness of 35 * 10 to the minus > 6; or .000035. I found a formula for surface brightness ( > http://en.wikipedia.org/wiki/Surface_brightness) that states S = m + 2.5 * > log10A where m is point-magnitude and A is the area in square arcseconds. I > went on my planetarium software and measured M1 to be approximately 440” X > 260” arcseconds or 114,400 square arcseconds. > > To further complicate maters I used an Excel spread sheet to do the math > for me so I could use it for different objects. Excel is telling me that > Log10(114,400) = 5.058, and plugging back into the formula 2.5 * 5.058 = > 12.6 and + 8.4 = 21. 21 is a loooong ways from .000035. I figure the > problem has to be in the Log10 area of my math. Or, they are saying to > different things from which I am confused. > > _______________________________________________ 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 Visit the Wiki: http://www.utahastronomy.com

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Re: [Utah-astronomy] Surface Brightness
by daniel turner 30 Mar '09

30 Mar '09

Jim: Your log10 math is correct. But the formula may be in different units than the 10 to -6 value your picked up from another source. DT --- On Mon, 3/30/09, Jim Gibson <jimgibson00(a)yahoo.com> wrote: > From: Jim Gibson <jimgibson00(a)yahoo.com> > Subject: [Utah-astronomy] Surface Brightness > To: "Utah Astronomy" <utah-astronomy(a)mailman.xmission.com> > Date: Monday, March 30, 2009, 8:31 AM > I Need help from some of you math > wiz-bangs. I looked up on a chart of surface brightness that > M1 has a surface brightness of 35 * 10 to the minus 6; or > .000035. I found a formula for surface brightness (http://en.wikipedia.org/wiki/Surface_brightness) that > states S = m + 2.5 * log10A where m is point-magnitude and A > is the area in square arcseconds. I went on my planetarium > software and measured M1 to be approximately 440” X 260” > arcseconds or 114,400 square arcseconds. > > To further complicate maters I used an Excel spread sheet > to do the math for me so I could use it for different > objects. Excel is telling me that Log10(114,400) = 5.058, > and plugging back into the formula 2.5 * 5.058 = 12.6 and > + 8.4 = 21. 21 is a loooong ways from .000035. I figure > the problem has to be in the Log10 area of my math. Or, they > are saying to different things from which I am confused. > > > > _______________________________________________ > 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 > Visit the Wiki: http://www.utahastronomy.com >

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Surface Brightness
by Jim Gibson 30 Mar '09

30 Mar '09

I Need help from some of you math wiz-bangs. I looked up on a chart of surface brightness that M1 has a surface brightness of 35 * 10 to the minus 6; or .000035. I found a formula for surface brightness (http://en.wikipedia.org/wiki/Surface_brightness) that states S = m + 2.5 * log10A where m is point-magnitude and A is the area in square arcseconds. I went on my planetarium software and measured M1 to be approximately 440” X 260” arcseconds or 114,400 square arcseconds. To further complicate maters I used an Excel spread sheet to do the math for me so I could use it for different objects. Excel is telling me that Log10(114,400) = 5.058, and plugging back into the formula 2.5 * 5.058 = 12.6 and + 8.4 = 21. 21 is a loooong ways from .000035. I figure the problem has to be in the Log10 area of my math. Or, they are saying to different things from which I am confused.

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Re: [Utah-astronomy] M45 and the moon
by Joe Bauman 30 Mar '09

30 Mar '09

That would have been cool! Thanks, Joe --- On Mon, 3/30/09, Jim Gibson <jimgibson00(a)yahoo.com> wrote: From: Jim Gibson <jimgibson00(a)yahoo.com> Subject: [Utah-astronomy] M45 and the moon To: "Utah Astronomy" <utah-astronomy(a)mailman.xmission.com> Date: Monday, March 30, 2009, 5:24 AM I got up early to get a chance to image the moon and M45 only to see a blanket of snow and cloudy skies. All I got was an image from my planetarium software of how I planed to framed the picture in my Orion 80mm ED. http://www.slas.us/gallery2/main.php?g2_itemId=1731&g2_imageViewsIndex=1 Jim _______________________________________________ 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 Visit the Wiki: http://www.utahastronomy.com

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M45 and the moon
by Jim Gibson 30 Mar '09

30 Mar '09

I got up early to get a chance to image the moon and M45 only to see a blanket of snow and cloudy skies. All I got was an image from my planetarium software of how I planed to framed the picture in my Orion 80mm ED. http://www.slas.us/gallery2/main.php?g2_itemId=1731&g2_imageViewsIndex=1 Jim

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remove from list
by Bill Kelley 29 Mar '09

29 Mar '09

Patrick, Will you please remove me from the list. I've been too ill to deal with it. Thanks, Bill Kelley

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Re: [Utah-astronomy] Found a comet (sort of)
by daniel turner 29 Mar '09

29 Mar '09

Erik: Comet 2008 T2 (Cardinal) is rather dim for casual amateur observing. It's at 12th magnitude and there are currently 8 brighter comets in the sky according to Seichi Yoshida's excellent website. http://www.aerith.net/comet/weekly/current.html It should brighten to 10th magnitude by June but will be in the wrong part of the sky for summer viewing. DT --- On Sun, 3/29/09, erikhansen(a)TheBlueZone.net <erikhansen(a)TheBlueZone.net> wrote: > From: erikhansen(a)TheBlueZone.net <erikhansen(a)TheBlueZone.net> > Subject: Re: [Utah-astronomy] Found a comet (sort of) > To: "Utah Astronomy" <utah-astronomy(a)mailman.xmission.com> > Date: Sunday, March 29, 2009, 8:38 AM > >Speaking of comets. Anyone see > Comet Cardinal? On 23 April it will pass > by M37. > > Erik > > > > While preparing to develop Friday night's test images I > came across > > three plates I'd put away long ago and never got > around to developing. > > > > So after finishing with Friday's shots I plopped the > three mystery > > plates in the developer. > > > > Alas, sitting at room temperature for what I can now > see were 12 years > > took their toll but the subject of the pictures is > recognizable: > > > > http://users.wirelessbeehive.com/~paw/temp/hb1997.jpg > > > > Hmmm, maybe I could pass them off as astro photos > taken in the 19th > > century. :) > > > > 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 > > Visit the Wiki: http://www.utahastronomy.com > > > > > > _______________________________________________ > 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 > Visit the Wiki: http://www.utahastronomy.com >

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Re: [Utah-astronomy] Found a comet (sort of)
by Joe Bauman 29 Mar '09

29 Mar '09

Hale-Bopp returns! --- On Sun, 3/29/09, Patrick Wiggins <paw(a)wirelessbeehive.com> wrote: From: Patrick Wiggins <paw(a)wirelessbeehive.com> Subject: [Utah-astronomy] Found a comet (sort of) To: "utah astronomy listserve utah astronomy" <utah-astronomy(a)mailman.xmission.com> Date: Sunday, March 29, 2009, 4:27 AM While preparing to develop Friday night's test images I came across three plates I'd put away long ago and never got around to developing. So after finishing with Friday's shots I plopped the three mystery plates in the developer. Alas, sitting at room temperature for what I can now see were 12 years took their toll but the subject of the pictures is recognizable: http://users.wirelessbeehive.com/~paw/temp/hb1997.jpg Hmmm, maybe I could pass them off as astro photos taken in the 19th century. :) 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 Visit the Wiki: http://www.utahastronomy.com

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Found a comet (sort of)
by Patrick Wiggins 29 Mar '09

29 Mar '09

While preparing to develop Friday night's test images I came across three plates I'd put away long ago and never got around to developing. So after finishing with Friday's shots I plopped the three mystery plates in the developer. Alas, sitting at room temperature for what I can now see were 12 years took their toll but the subject of the pictures is recognizable: http://users.wirelessbeehive.com/~paw/temp/hb1997.jpg Hmmm, maybe I could pass them off as astro photos taken in the 19th century. :) patrick

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Re: [Utah-astronomy] USNO-B1.0
by Joe Bauman 29 Mar '09

29 Mar '09

Speaking of planes: who was doing the touch-and-gos-and-flips at Wendover? -- best, Joe --- On Sat, 3/28/09, Patrick Wiggins <paw(a)wirelessbeehive.com> wrote: From: Patrick Wiggins <paw(a)wirelessbeehive.com> Subject: Re: [Utah-astronomy] USNO-B1.0 To: "Utah Astronomy" <utah-astronomy(a)mailman.xmission.com> Date: Saturday, March 28, 2009, 11:25 PM Hi Joe, On 28 Mar 2009, at 23:12, Joe Bauman wrote: > Patrick, That sounds exciting. I guess we could put it on an external hard drive -- is that right? Yes. You take him your drive and he'll copy it at no charge. Or he'll sell you a 500 GB drive with the catalog already on it for $100 if you pick it up. > What is used to see the images? Is there a special viewer? It's not a picture type catalogue. Rather it's used in conjunction with planetarium software and the software plots the stars on the virtual sky. > (PS: I gather no telescope class tomorrow!) I've been holding off making the announcement but now that you ask I guess I'll make it official: Class postponed. Of course the bad weather is all because I just got word that my plane (complete with its new, more powerful engine) is ready to fly again after weeks of being down. So now the weather closes in so I can not look at or fly in the sky... _______________________________________________ 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 Visit the Wiki: http://www.utahastronomy.com

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