NGC 3718 a horror story

[DaveS]

This is a truly horrible image of NGC 3718 captured on the 16th and 17th with the ODK 12 / G3 16200. 15 x 600 sec subs of Red and Green, 21 subs pf Blue. Stacking in DSS with full calibration, linear stretch in Affinity then Gradient Reduction (Many iterations), RGB synthesis, and colour balance (Two iterations) in Astro Art 7. Also applied heavy noise reduction.

I've found that the 16200 camera with Chroma filters needs a lot more Blue that the other channels, and could probably use 900 sec subs rather than the 600 that I normally use.

If I were getting a camera for the ODK now there is no way I'd be looking at a 16200 camera. Old tech, noisy and insensitive. Might eaven sell it and get one of the IMX 455 cameras.

[Andrew*]

I'd love to get images as horrible as this!

Looks very fine to me and a really interesting looking galaxy.

[DaveS]

Thanks Andrew, but the background is very uneven despite some pretty fierce gradient removal iterations.

[Andrew*]

Now you've pointed it out, I can see what you mean. Wouldn't have seen it otherwise!

I remember this pain from processing a widefield of Orion once, with a pink amp glow gradient on two corners, orange LP gradient from another corner and vignetting...  😩

This is one reason I mainly do visual now.

Still, noise aside, beautiful signal 😎

Edited April 18, 2021 by Andrew*

[Taman]

It looks good to me, I bet you get more likes than my version! 😁

Tony.

[DaveS]

After discussion with @Jkulin elsewhere I ran an initial G2v calibration trial, finding that the Blue channel needs 1.74x the exposure that the Green and Red channels need. I think it was @Laurin Dave who first alerted me to that possibility.

I have no idea as to when I will be able to get more data with the calibrated values as the moon is now getting too bright for worthwhile RGB. H-alpha is still just viable, but think there is very little here.