20220204 - M42 (ORI) - Orion up close, but stopped in its tracks by clouds and filter-halos
What’s in the picture(s) -
https://en.wikipedia.org/wiki/Orion_NebulaQuote “The Orion Nebula (also known as Messier 42, M42, or NGC 1976) is a
diffuse nebula situated in the
Milky Way, being south of
Orion's Belt in the
constellation of Orion. It is one of the brightest
nebulae and is visible to the
naked eye in the night sky. It is 1,344 ± 20
light-years away and is the closest region of massive
star formation to
Earth”What was the experience
Following last’s year 1 hour test-shot with my TS140 scope, the plan was to capture M42 now with a longer integration time, bringing out the fine detail, and going for a SHO capture instead of RGB
That was the plan …
I had to wait until January, until M42 had sufficiently cleared the trees to allow for a lengthy enough viewable window. But then, of course, the clouds and full moon messed up the planning. Only 2 nights captured so far, with a lot of the captured data lost to bad focus, as the ASIAIR seemed to struggle with getting in focus on the Ha and Oiii after the January update. Only clouds forecasted for the foreseeable future and the viewable window to capture more data is getting (too) short, as M42 is already quite low to the horizon.
On top, I had gone for 120s exposures, thinking that would’ve been advisable for the Ha and Oiii compared to the RGB, but that seems to be borderline not to over-expose the core and the Trapezium. In addition, this exposure time seems to cause halos, both in Ha and Oiii
So, I processed the 3 hours of data anyway, which is far from the total time that I wanted, and got annoyed with the halos in the capture, in spite of the fact that the filters are optimised for f10-f3.5, which should’ve been ok for my fast TS140
So, this is how far this image will go. I prefer to restart the capture at shorter exposures, hoping to avoid the halos. As for this data, maybe I’ll have a bit of learning by combining it with the test-RGB data from earlier
How it was done
Scope: TS140 APO (FL 910mm)
Mount: CEM70G
Camera: ASI2600MM Pro
Photons:
20220127 Ha 120s 29x Oiii 120s 16x
20220204 Ha 60s 23x 120s 30x Oiii 1x
Processing: PixInsight (Mac)
What have I learned from this
Doing everything right, doesn’t necessarily mean that the end-result will be right as well. This image isn’t the perfection that I was going for. Somehow I’m wondering why filters that are labelled to be ‘optimised’ for fast scopes, still result in annoying filter halos, even at 120s.
Another learning point is to adjust my workflow for processing the stars, now done together with the image. Perhaps I need to separate them out during the processing, hopefully this is a way to get better control over the filter-halos. Either that … or a different brand of filters
Clear Skies everybody! 🤩✨🔭
Follow me @astrowaut
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