NGC-891: A Fall Favorite (Joel Shepherd)

NGC-891: A Fall Favorite

This is a favorite fall galaxy: NGC-891, processed with just under 6 hours of RGB and an additional hour of Ha.

Something I didn't know about this galaxy before: it is very rich in Ha signal, almost to the point that the Ha resembles luminance. Not just blobs here and there, but a whole cloud of it. If you zoom in, the dust structures are interesting. There's speculation that the fine filaments or threads were created by supernova explosions, or that they've formed by stellar winds.

Imaging remotely in New Mexico continues to go well, but there's definitely a learning curve. I've crashed the mount twice: the second crash was a bad one which took out the filter wheel on my ED80: a bummer because it prevented me from getting flats for several nights worth of imaging. And the internet service is a little hit or miss -- some days there's internet, and some days there's not -- which is maybe unsurprising given the remoteness, but it still requires some patience to deal with. When things are dialed in, though, it's rewarding.

Oh, right. The reason it took so many nights to collect a relatively small amount of data was due to focuser challengers. As the air cools, the focusing point moves inward: somewhat counter-intuitive, but there it is. By the time the ambient temperature got down to 0c, the focuser was almost bottomed out -- drawn in as far as possible -- and the autofocus routine would fail. Hence, I threw out a ton of out-of-focus lights. The solution required Moonlite to machine a new flange that sits in between the focuser body and the OTA, just 2mm shorter than the stock flange, but that was more than enough. Now I'm back to happily focusing all night long. Ron at Moonlite and Yuri at TEC, as usual, were great about helping me troubleshoot and solve the problem with minimal fuss.

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Status	Advanced success
Started	...
Astrometry.net job	5302344
PixInsight job	1GDP21IRB24K3JCLLJCVWFG2PTUBEQPC
PixInsight queue size	n/a
PixInsight stage	TASK_LOG

RA (center)	02h22m29s.80
RA (top/left)	02h23m58s.31
RA (top/right)	02h20m59s.10
RA (bottom/right)	02h21m00s.58
RA (bottom/left)	02h23m58s.49

Dec (center)	+42°20′47″.1
Dec (top/left)	+42°35′15″.2
Dec (top/right)	+42°35′04″.9
Dec (bottom/right)	+42°06′13″.3
Dec (bottom/left)	+42°06′24″.8

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