M42 - navigating the Orion Nebula (Tom Gray)

M42 - navigating the Orion Nebula

A year since I took my first digital image of the Orion nebula (my earlier ‘emulsions’ were always overexposed, or suffered manual guiding issues - remember that?). Given the rather unsteady conditions we have been 'enjoying' (RMS matching the arcsec/pixel scale), and failure to address backfocus issues with my current setup, I'm rather pleased with the outcome.

75m data captured in 60s L, 120s narrowband, 30s R,G,B in Envisage, stacked and aligned in Nebulosity before processing in Startools. There was severe vignetting and some very odd shaped stars at the edge of the field, and I forgot to take any flat fields. Surprisingly the image was easy to process in Startools, with stretch, wipe, stretch, HDR brightening, deconvolution, colour saturation, noise equalisation followed by final repair to warped stars. Certainly better than my earlier efforts.

I used my dual narrowband filter to bring out more detail (and reduce sky glow from waning moon) and processed as an LLRGB image. Shorter exposures helped to reduce burning out the core, and once I’ve sorted the focal reduction I will try again, with a range of exposures to maximise the detail and contrasts in this crucible of star production. Navigating pre- and post-processing, and the fine detail in this amazing nebula requires better planning and setting sail again (and again) in, hopefully, better conditions.

Original
B
C
D
Final
E

B

Description: Here is a version stacked and aligned in Penumbra (an old but effective program developed by George Morimosato for DSI) with HDR brightening and gentle sharpening, but no further processing. I like this 'less is more' image, even with severe vignetting.

Uploaded: ...

C

Description: I took the Penumbra version (B) and processed it again using Startools. I've been rather heavy handed with HDR and deconvolution; the core is a mess and perhaps oversaturated the colours...but the detail kept on popping out! I'll try this again, and curb my enthusiasm. Ouch!

Uploaded: ...

D

Description: My final, and I hope more sympathetic revision. Not too bad for 1.2 hours IMHO 🤔

Uploaded: ...

E

Title: M42 - reprocessed again

Description: This winter, I have been busy playing with my new camera, and have not made the time to produce a new image of the Great Nebula in Orion. As with others, I have been using this stormy weather to reprocess some data from 2020. Whilst I quite liked the vivid colours in revision D, this is perhaps more natural and shows off the pink hydrogen emissions. This revision comprises 30m L (taken through my Optolong L-eNhance tri-band filter) and 30m RGB using my Meade DSI III pro mono camera. The stars are still terrible in my f3 reducer!

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Schmidt-Cassegrain Telescope (SCT) Imagers
Altair Astro 183 M/C Hypercams
UK Astro-Imaging
Optolong L-eNhance filter

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Status	Advanced success
Started	...
Astrometry.net job	4036090
PixInsight job	IGJHDVVGX6K6C9CMHCXB2UC1NL6RI0WD
PixInsight queue size	n/a
PixInsight stage	TASK_LOG

RA (center)	05h34m57s.48
RA (top/left)	05h33m01s.93
RA (top/right)	05h36m48s.28
RA (bottom/right)	05h36m53s.29
RA (bottom/left)	05h33m06s.16

Dec (center)	-05°34′51″.3
Dec (top/left)	-05°54′32″.9
Dec (top/right)	-05°56′05″.0
Dec (bottom/right)	-05°15′14″.3
Dec (bottom/left)	-05°13′34″.8

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