NGC 4236 - A Galaxy in Draco (wadeh237)

NGC 4236 - A Galaxy in Draco

This is NGC 4236, a barred spiral galaxy in the constellation of Draco.

I'm not sure why this isn't a more popular target. Its apparent size is fairly large, at least as galaxies go, and fairly bright at magnitude 9.7. I took this image over 5 nights at Table Mountain Star Party, from 7/26 through 7/30 of 2022.

The capture system was as follows:

Scope: Astro-Physics Starfire 130GTX
Mount: Astro-Physics AP1100-AEL
Camera: QSI 690-wsg8 with 1.25" Astrodon filters
Capture Software: NINA, PHD2
Processing Software: PixInsight

The exposure data was as follows, all binned 1x1:

49x600 seconds luminance
23x300 seconds red
20x300 seconds green
23x300 seconds blue

Because of the late season, and location of the galaxy, each night was only about 3.5 hours, and the elevation was fairly low. I was shooting this right over the top of my motorhome. It also seems to be located in an area rich with satellites. Probably 75% of the subs had satellite trails, most of them with multiple trails. There were a couple of frames with nearly a dozen trails. I integrated them with Generalized Extreme Studentized Deviate and had to crank up the ESD Significance setting to 0.9 to get reasonable rejection of all the trails.

Original
B
Final
C

B

Description: This is a reprocess of the original data that I captured at Table Mountain Star Party 2022.

Shortly after the star party, I had a system failure and lost some data. I have a backup plan for important data, which includes all of my astronomy raw data, as well as most fully completed projects. Unfortunately, I hadn't yet moved the project for this object to long term storage, so I lost the project.

This image is a rework of the original data, starting from scratch, but taking advantage of the current set of tools available in PixInsight. I didn't have any particular goals in mind during the reprocess. I was mainly just replacing the lost project and using as a processing exercise.

I blinked back and forth a few times between the original one that I uploaded and the new reprocess. They are pretty similar, but I found myself saying to myself "Hmm. I think that I like the old one better.", which surprised me a bit. Then, I realized that I had them mixed up, and I like the new one better. Whew.

I also compared it to some others that I found on the web. I think that mine holds up pretty well. I did notice that some of the better ones that I looked at (by astrophotographers whose names I recognize) seemed to be more aggressively noise reduced. I'm finding that I don't really like seeing really smooth data in the faint areas. Some of the new noise reduction tools, like NoiseXTerminator, make it really, really easy to get super smooth images. I prefer a bit of graininess. To me, it just looks a bit more natural. This version could probably stand just a bit more noise reduction, but I've opted not to do that for now.

Uploaded: ...

C

Description: Ok, so blinking the original and revised version here on Astrobin, I decided that the background of the revision was way too bright, so I darkened it a bit and now have a 3rd (maybe final) version...

Uploaded: ...

	Distinct awarded users	Total awarded images
Image of the day
Top picks
Top pick nominations

	Image of the day	Top pick	Top pick nominations	Total submitted
Deep sky
Solar system
Extremely wide field
Star trails
Northern lights
Noctilucent clouds
Landscape

	Image of the day	Top pick	Top pick nominations	Total submitted
Backyard
Traveller
Own remote observatory
Amateur hosting facility
Public amaeteur data
Professional, scientific grade data
Mix of multiple sources
Other
Unknown

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Status	Advanced success
Started	...
Astrometry.net job	6861143
PixInsight job	SILKVP5001CKMJV62MCDZ022VHM9MDGL
PixInsight queue size	n/a
PixInsight stage	TASK_LOG

RA (center)	12h16m39s.267
RA (top/left)	12h21m17s.370
RA (top/right)	12h12m01s.698
RA (bottom/right)	12h12m09s.737
RA (bottom/left)	12h21m09s.407

Dec (center)	+69°27′31″.35
Dec (top/left)	+69°45′57″.23
Dec (top/right)	+69°45′56″.43
Dec (bottom/right)	+69°08′43″.40
Dec (bottom/left)	+69°08′43″.30

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