M101 - in a spin (Tom Gray)

M101 - in a spin

M101 is a lovely face-on spiral, perfectly placed for imaging at the zenith. With a long clear night ahead, I was excited; the live stacked image looked great coming off the camera.

After that things went rapidly downhill - my flats failed to deal with the significant vignetting from my f3.3 focal reducer, resulting in unsightly artefacts and gradients. This image has taken me by far the longest to process.

Initially stacked in ASTAP, I could not get my filter stacks aligned, despite using astrometric solving, and half my frames were dropped due to quality. ASTAP also muddled up my data, backing up and replacing files.

I resorted to manual alignment and stacking the remaining frames in Nebulosity, expecting a straightforward workflow in Startools. Not so, this image is the result of the most convoluted workflow, I have ever undertaken, and has left my head in a spin!

Suffice it to say, this is a poor representation of M101. What is so frustrating is that the raw data appeared good. So, what have I learned? Don’t make assumptions, back up the raw data before processing, and work the problem. I will try again one cloudy night, but now I’m going to lie down!

Original
B
Final
C

B

Description: WHAT a difference some proper pre-processing makes in ASTAP (thanks again @rich-sky). Exactly the same data taken from ASTAP, processed in Startools, using the defaults. A little removal of a few dust bunnies and artifacts from poor quality flats. Voila!

Given the relatively short 120s exposures and 118m integration (Lx24, Rx14, Gx8, Bx13) I'm pleased with the overall depth, detail and colour. I'll keep the other, just to remind me how aweful it was!

Uploaded: ...

C

Description: I've had another go trying to preserve the detail but reduce the noise (in the gradients from poor flats). The star spikes are just for fun, but represent the true star colours.

Uploaded: ...

Schmidt-Cassegrain Telescope (SCT) Imagers
Altair Astro 183 M/C Hypercams
UK Astro-Imaging
Low-Cost Astrophotography

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Status	Advanced success
Started	...
Astrometry.net job	4419486
PixInsight job	GH3YD37DFBSYSLA747V3EBPH8ZDS3DLA
PixInsight queue size	n/a
PixInsight stage	TASK_LOG

RA (center)	14h03m17s.54
RA (top/left)	14h05m59s.36
RA (top/right)	14h00m51s.88
RA (bottom/right)	14h00m37s.87
RA (bottom/left)	14h05m41s.47

Dec (center)	+54°20′15″.3
Dec (top/left)	+54°35′07″.8
Dec (top/right)	+54°38′17″.1
Dec (bottom/right)	+54°05′11″.2
Dec (bottom/left)	+54°02′04″.1

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M101 - in a spin

M101 - in a spin

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M101 - in a spin

M101 - in a spin

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