Howard B
August 17th, 2020, 01:01 AM
Emission nebula
Vulpecula
RA: 19 40 22
DEC: +27 18 34
Magnitude: approximately 13 (guess)
Size: 1.0’
I was observing from my backyard a couple nights ago and, on a whim, decided to have a look at NGC 6813. Cygnus was in a good position relative to my house and nearby trees, and when I opened Interstellarum to chart 30, my eye almost immediately fell on NGC 6813. Just two degrees east of Albireo and only a half degree into Vulpecula, the small rectangular symbol printed on chart 30 implied it was a small, faint nebula.
3980
I thought it would be an unremarkable reflection nebula, but NGC 6813 turned out to be much more interesting than that. It was easy to sweep up with my 28-inch under 20.40 SQM skies, and it appeared as a small, elongated slash of nebulosity at 155x, my low power. I’ll guess it’s approximately 13th magnitude, and I’m guessing only because I can’t find a source that quotes a magnitude. Anybody know where to find the magnitude for 6813?
Regardless, it was an easy catch under a semi-dark sky, and during exceptionally poor seeing conditions. Even though I was thinking this was a reflection nebula I tried my NPB filter - and whoa – 6813 increased in apparent size by about 10 times! The OIII filter gave noticeably higher contrast, and now 6813 looked like a nice round planetary nebula. I bumped up the power to 408x for the best view.
3978 3979
There’s a star in its center – EM* VS 33 – which is a 13th magnitude emission line star (http://simbad.u-strasbg.fr/simbad/sim-id?Ident=EM*+VES+++33&NbIdent=1). It was best seen without a filter, and has a faint companion to its south, and a brighter companion about four times as far away, to its north. Given the poor seeing I’m surprised I could see these stars at all. All three have a very different Gaia parallaxes so they aren’t physically associated.
The best image I’ve found of 6813 is at http://www.spacebanter.com/attachment.php?attachmentid=5461&stc=1, and the photographer posted more info at https://www.cloudynights.com/topic/485827-ngc-6813-interstellar-matter-aka-emission-and-reflection-nebula/
All in all, NGC 6813 was a fun surprise and showed up well in less than optimal conditions – and is a good reminder of the treasures waiting just off the beaten path.
Give it go and let us know!
Vulpecula
RA: 19 40 22
DEC: +27 18 34
Magnitude: approximately 13 (guess)
Size: 1.0’
I was observing from my backyard a couple nights ago and, on a whim, decided to have a look at NGC 6813. Cygnus was in a good position relative to my house and nearby trees, and when I opened Interstellarum to chart 30, my eye almost immediately fell on NGC 6813. Just two degrees east of Albireo and only a half degree into Vulpecula, the small rectangular symbol printed on chart 30 implied it was a small, faint nebula.
3980
I thought it would be an unremarkable reflection nebula, but NGC 6813 turned out to be much more interesting than that. It was easy to sweep up with my 28-inch under 20.40 SQM skies, and it appeared as a small, elongated slash of nebulosity at 155x, my low power. I’ll guess it’s approximately 13th magnitude, and I’m guessing only because I can’t find a source that quotes a magnitude. Anybody know where to find the magnitude for 6813?
Regardless, it was an easy catch under a semi-dark sky, and during exceptionally poor seeing conditions. Even though I was thinking this was a reflection nebula I tried my NPB filter - and whoa – 6813 increased in apparent size by about 10 times! The OIII filter gave noticeably higher contrast, and now 6813 looked like a nice round planetary nebula. I bumped up the power to 408x for the best view.
3978 3979
There’s a star in its center – EM* VS 33 – which is a 13th magnitude emission line star (http://simbad.u-strasbg.fr/simbad/sim-id?Ident=EM*+VES+++33&NbIdent=1). It was best seen without a filter, and has a faint companion to its south, and a brighter companion about four times as far away, to its north. Given the poor seeing I’m surprised I could see these stars at all. All three have a very different Gaia parallaxes so they aren’t physically associated.
The best image I’ve found of 6813 is at http://www.spacebanter.com/attachment.php?attachmentid=5461&stc=1, and the photographer posted more info at https://www.cloudynights.com/topic/485827-ngc-6813-interstellar-matter-aka-emission-and-reflection-nebula/
All in all, NGC 6813 was a fun surprise and showed up well in less than optimal conditions – and is a good reminder of the treasures waiting just off the beaten path.
Give it go and let us know!