First light with mono ... small beginnings with M20 Triffid Nebula
After what seemed like an eternity (... twas only weeks lol!) I had the opportunity to use my first ever mono setup. I choose something comparatively bright to make post-processing 'easier' (if there's any such thing): M20 Trifid Nebula. This is a very humble beginning for my journey into the dark art of mono and I have much to tweak (backfocus) and learn about processing multiple wideband and narrowband of channels. I captured about 6hrs of SHO data (~2hrs each) and about 8hrs LRGB data (~2hrs each) but haven't yet processed the SHO data.
Soooooo here's my first ever LRGB image inclusive of funky coloured stars (RGBG combo and stretch problem?) and some egg shaped stars (back focus?). This is my 4th attempt at processing the data ... mono is not as 'straightforward' as OSC but I like what I'm seeing in the final result. I was particularly happy to see the stellar jet and stalk reasonably well resolved (in blown-up image) - I thank Dave882 for highlighting those in a fantastic M20 image he took this time last year. I also like having the ability to use all those SHO & LRGB channels in whatever way I want :-) That said, my OSC cameras will still get plenty of use.
Integrated in APP (which makes it soooo easy) and processed in PI, with final tweaks in PS. I did learn that in PI, it seemed better to incorporate the L channel AFTER processing the RGB channels but others may have a diff experience.
Edge HD 8" with 0.7 R, ASI294MM, Antlia LRGB
160 x 180s LRGB (2hrs each, 8hrs total)
APP, PI, PS
As always, all advice/critique/help is gratefully received. Thanks for looking. Alex
Fantastic capture Alex. I haven't got around to LRGB yet, waiting to get a better filter set to use. Considering maybe getting a 294MC instead & use that for the the stars instead.
But keep up the great work, look forward to seeing your future efforts, especially with much more data.
Alex, cracker of an image mate. Good amount of data with a great setup equals nice images. Your processing is very nice, I personally love the colours and the stars are really good.
BRAVO! Take a bow mate. You got it in one, congratulations. See, I told you it was easy
I can't fault it, but funky colours are fixed with SPCC. I can't see eggs either, maybe a little "comety", so the finest of tweaks on the collimation, although getting appropriately good seeing in order to make that tweak is not easy, or you know, just not care .
One rule of thumb, you should aim for an integration time (regardless of exposure time) of L = R+G+B eg: if you're using the same exposure lengths then for every "loop" 1xR, 1xG, 1xB & 3xL
Wow what a fantastic shot!! Colour is beautiful, detail is superb. I’d love to have a look at that in high res if you get the chance to post a link.
Thanks for your kind words too. Glad to see you’re making good progress with PI. I’m also still relying onAPP for stacking while post processing in PI but a while off before I go mono. Looks like you’re smashing it tho!! Well done!
Looking at this reminded me of what a packed star field surrounds this nebula, you just don't see it in most images posted. I only really noticed it when I pointed a DSLR at it a while back...
Thanks everyone, I appreciate your feedback and I'm very keen for some more clear weather this weekend :-)
Mark - I took a (very poor) wider field image of M20 late May 22 and it is *full* of stars to the point of distraction - the star fields are a sight to behold. Re using a 294MC for stars, it seems like a common thing to do. I have that camera and was thinking about doing the same but that would depend on how much time I have.
Dave - PI is awesome but will break your brain I'm spending a lot of time in PI but still use APP a lot. I find for some targets, eg. galaxies, AAP produces better colours with little more than a few tweaks of saturation. Btw, a higher res version of my M20 is here. Apologies in advance for the comet-like stars on the LHS, my SCT's collimation needs a solid tweak ... if I actually care enough (per John's comment )
John-dude - mate, thanks for the hot-tip about L integration time; I did't know that and will def follow that rule-of-thumb. When do you roll the L ch into your workflow? After you've finished the RGB or SHO processing?
The SHO version of my M20. It looks completely different to the LRGB version (including OIII halos, dammit); I didn't expect it to look so different but I don't mind it. I didn’t process each channel separately and might have a crack at that and see if I can reduce the halos. I also might do a foraxx version then post all three (LRGB, SHO, foray) for a comparison. Might also be interesting to blend the SHO/foraxx with the LRGB image. Alex
I don't add L to SHO as a rule, I have a couple of times but the H usually makes a better L than the L itself. With LRGB, lately I've been adding it at the end because that's what the tutorials said to
Boy that SHO version sure changes the object and structure.
Looking forward to all the palette bending.
That’s a really interesting image in SHO. Have to say I think I prefer the RGB but still a worthwhile effort. By the way- the full scale image is wonderful and those stars imho are pretty darn good for an sct. Guess that’s the advantage of the edge. I agree APP does a wonderful job for stacking, gradient removal and colour calibration. In PI do you do the photometric colour calibration? I found that it does a pretty good job and possibly introduces a bit less noise than APP colour calibration.
Great stuff Alex...try taking both your images into Photoshop and layering them then using the rubber tool to add bits from one to the other..
Not cricket but just so much fun
Thanks everyone ... yep, the SHO version was different! I've continued the fun of having SHOLRGB data and produced a foraxx version that is, well, it just is ... different too I've taken Alex's advice and blended/mangled the 'plain' SHO, foraxx SHO and LRGB versions (in PI, not PS - sorry mate) just because it is indeedee el geeko funness. I'm still tweaking that blended image but will share tonight for a giggle.
Dave - I do use the photometric colour calibration early in my workflow which goes something like: SCNR->A/DBE->image solver->SPCC->(SCNR again, maybe)->noiseX->blurX->starX->stretching/histograms, colours, saturation, intensities, blending etc. I'm still learning about the many (many) PI tools and squillions of ways of doing things ... it'll be a loooong multi-year journey. For example, the multi-level tools (HDR etc) are interesting and I'm trying (unsuccessfully atm) to use them too. Also, I'm now processing stars separately to the main target for all images and using a mix of arcsinh and histogram stretching to draw out star colours provided by SPCC without making them look too gawdy.
John - I'm not yet brave enough to do anything other than what the tutorials say. A kinda 'stay on the roads, keep clear of the moores' thing
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