Mike in Rancho wrote: ↑Mon Oct 09, 2023 5:40 pm
Your GHS versions really make the Crescent pop out. Looks cool. But, too much? I wonder if something similar could be done with ROI and/or IFD settings, with the softer nebula clouds but sharper Crescent. Or is that too artistic?
Oh, too too much. Bet it would be popular on CN
Mike in Rancho wrote: ↑Mon Oct 09, 2023 5:40 pm
Also in both GHS - where are all the stars?
I have no idea whatsoever what you could possibly be talking about...
Carles wrote: ↑Mon Oct 09, 2023 7:18 pm
@Mike in Rancho Right, I have tried ICE for post processing images, with OK results. Although as you mention, processing of the different parts of the stitch needs to be stretched or processed more or less equal, and that is sometimes hard to do.
Other issue with Astap stitch is sometimes some dark artifacts it creates that Wipe don't like much, and depending on the dataset, even colour overlaping creates a bit weird stuff.
Not as bad, but when trying mosaic + preprocessed Halpha and Oiii, here comes the trouble, as the seams are very distinct on Oiii, and it makes it look weird.
We need AI! Or Ivo to write a mosaic algorithm.
Problem is, it probably requires both stacking and post-processing elements. Star alignment to match the correct overlaps of course, as well as global brightness normalization. BUT, I think a perfect mosiac would also require gradient and field flattening i.e. Wipe, local brightness normalization, and - if necessary (data mining?) a matching initial color case floor and white balancing.
Then one could hopefully have an entire usable stitched linear file.
dx_ron wrote: ↑Tue Oct 10, 2023 3:32 pm
CN comment I noticed, from a PI user:
I feel like I did something wrong in the linear stage (I did use Narrowband combination) because I cannot get a good mask to increase the blues
Ya. Saw that. But done right (relative emissions are lost but that's understood), the Blanshan combination (now integrated into the latest PI release) already boosts the weak channel (often Oiii) to desired degree, you wouldn't need extra selective boosting by mask. If there's Oiii even there, that is.
But all of that is just passe now. The old thing. A lot of images are so lacy and BXT'd now that my eyes hurt. So overdone that it doesn't even look "plausible" i.e. BXT makes your scope as good as the VLT in Atacama. They look beyond VLT.
In looking at the Siril GHS Crescent - at least some of the "over-pop" might be perception caused by blowing out the Oiii bits (the bright white looking parts). I'll go back and try some heavy-handed Highlight Protect.
Back to the Bubble (and back to ST). I added more duoband time (up to 8.3 hours). And I added 5.6 hours of OSC. With this framing an OSC + NBAccents approach seems logical. I did play the "undo to bg" game in Layer. It greatly reduced damage to the stars, but I have not yet completely eliminated it.
Bubble_NBa_mask-reverse_blend380pct_1600.jpg (695.35 KiB) Viewed 15239 times
Yes come to think of it I've seen that before with a buddy's RASA Cal Neb dataset I played around with. His PI GHS (and who knows what else) edit turned a lot of the structure bright white. It was impressive looking and nicely made those finely woven nebulous streamers pop out, but I couldn't make any sense of how he got it or what it might mean. Especially after I examined each filter file and didn't see what would seem to be blending of emissions (regardless of relative weighting) that could cause it. Who knows.
One thing I learned by following recent 'scientific vs artistic' talk is that red stars look way better with artistic color. Redid my ET OSC and arrived at a point where I am OK with how the Garnet Star blends in.
ET+OSC_nebula-stinks_Garnet_star_OK.jpg (703.89 KiB) Viewed 14952 times
The file name tells you what I think about the nebula colors... This is with the identity matrix and trying to tone down green.
So I updated my old copy of GIMP and loaded up the file. No clue what I *should* be doing there, but trying out a bunch of tools from the color menu I ended up with a bit of color temp adjustment and saturation.
ET+OSC_after_Gimp.jpg (712.99 KiB) Viewed 14952 times
I really like the Bubble, especially the one with more nebulosity. In my experience a difficult target, at least I was struggling to get a picture out...
The trunk is also pretty cool. I like the unconventional coloring of the pre GIMP version The Garnet star doesn't distract but it has an odd coloring, doesn't it? All stars are blue and the Garnet is orange. Is this a pure NB image or does it contain broadband data (sorry if you already specified it and I missed it)? Maybe a masking effect?
I really like the Bubble, especially the one with more nebulosity. In my experience a difficult target, at least I was struggling to get a picture out...
Thank you, Stefan! I haven't decided yet how to make a "final" presentation.
The trunk is also pretty cool. I like the unconventional coloring of the pre GIMP version The Garnet star doesn't distract but it has an odd coloring, doesn't it? All stars are blue and the Garnet is orange. Is this a pure NB image or does it contain broadband data (sorry if you already specified it and I missed it)? Maybe a masking effect?
The color of the star is quite magnificent and has been the source of some discussion. It is most often described as "a deep red" or "reddish orange" but has sometimes been noted as "orange" and even having "a purplish tint".
and
A Note About Color:
Dr. Philip Steffey points out that the color of Mu Cep will most likely NOT appear red to the naked eye. He states, "The only way Mu Cep can appear red to the naked eye is due to extreme chromatic scintillations. In ordinary binoculars, which boost the star's apparent magnitude to -0.5 to +1, the color at medium altitudes is yellowish orange, roughly 30% saturated, similar to that exhibited in the first picture of this article. Large binoculars and telescopes yield a more yellow and paler color. The steady naked-eye color is brown--degenerate yellowish orange, for the illuminance factor is under 9--very dark gray to soft black on a daytime grayscale. These colors agree with subphotopic model predictions I'm developing."
He continues, "W. Herschel's 'garnet' comparison was unfortunate, for many succeeding observers have mindlessly accepted this as meaning red or reddish orange. Actually, garnets come in 19 hues including blue, yellow, and green. Are we certain about the variety Herschel meant? And was he reporting naked-eye or optically aided observations? If the latter, he may have been fooled by chromatic aberration produced by nonachromatic eyepieces."
For more information on the colors of stars - including common misconceptions - consult the article, "The Truth About Star Colors", by Philip Steffey in Sky and Telescope, September, 1992, p. 266.
