M42 - the Good, the Bad and the Ugly

[Mike in Rancho]

Good going Ron, glad the new equipment is working as planned.

For a more accurate test though, I'd think you'd have to try to process them a bit more equivalently. M[agenta]42 seems to have a greater stretch, and perhaps different channel balance.

You'd probably have to just eyeball it rather than duplicate log settings, as with the acquisition now different it's likely that dynamic modules like Wipe and OptiDev will produce different results. Not to mention color channels will have different stuff in them.

But it seems promising. Slightly worries me as well, as my Optolong LRGB set seems to edge over left of 400 by a fair amount.

[dx_ron]

I wasn't going for a full-on comparison test, as there's little cost (image-quality-wise) to using the more stringent filter.

Your LRGB imaging shouldn't be impacted, because you're using a newt, right? The RGB part won't be affected regardless, as long as you focus for each filter. The L could have some star-size issues if your using a less than perfectly corrected refractor. Even with a refractor, the need for the L3 filter depends on the telescope. My AT65EDQ shows zero issues with the wider uv/ir filter.

[dx_ron]

Of course a possible fix, other than perhaps fringe killer on the purple, would maybe be a post-tracking invert-green-cap?

It's been cloudy, of course - so I went back and re-processed with the current alpha. In addition to jacking up gamma post-tracking I thought I'd go back to this off-the-wall-sounding suggestion of yours. Set RGB:RBG, cap green 100%, Keep. Open color again to put back to RGB. Interesting.

M42_739x15s_norm_RBG-cap_gamma-boost_1.25+740k.jpg (646.32 KiB) Viewed 18096 times

Upon pixel pre-peeping (before Mike gets to it), I found a weird dark artifact to the lower-right of a lot of stars. Here's a crop of one where the artifact actually makes a donut. This is in the purple-star version. I need to go back and start over to see where it first appears. It's not there in the initial OptiDev.

star.jpg (18.89 KiB) Viewed 18096 times

[Mike in Rancho]

It's been cloudy, of course - so I went back and re-processed with the current alpha. In addition to jacking up gamma post-tracking I thought I'd go back to this off-the-wall-sounding suggestion of yours. Set RGB:RBG, cap green 100%, Keep. Open color again to put back to RGB. Interesting.
M42_739x15s_norm_RBG-cap_gamma-boost_1.25+740k.jpg

I can't take credit! I think you invented something new.

So based on your description, it seems you swapped G and B, and thus running green cap turned it into a blue cap.

The purple or magenta cap I am aware of actually uses the Layer module for a full inversion (green and magenta being opposites), after which you'd green cap and then invert back.

Of course the M42 and Running Man region is replete with colors, including I believe blues, purples, and greens, so any kind of global capping could end up altering too much.

Upon pixel pre-peeping (before Mike gets to it), I found a weird dark artifact to the lower-right of a lot of stars. Here's a crop of one where the artifact actually makes a donut. This is in the purple-star version. I need to go back and start over to see where it first appears. It's not there in the initial OptiDev.
star.jpg

I wonder if this is the same as what Dietmar pointed out a few days back. And I've seen it before also. Did you have intra iteration + centroid tracking turned on in SVD? That might help alleviate it. Or look for a star sample that wasn't very good.