Hello,
Updated to latest nightly and was pleased to see some improvements in FITS viewer histogram department.
It looks much better now and is actually useful. However, it cuts the histogram too aggressively from the right side (where all the nebulosity is) and the images also look blown up.
I am shooting Orion right now (My first CCD session. Just got an ASI1600MC to replace a DSLR).

Here's Ekos histogram/image


Here's the same image (saved) in FitsWork


Thanks!

Can you post a link to the FITS file please?

I am not sure how. The fits file is 16mb. Here's zip.
Thanks!

It's an 8bit image. I am still to check this but DSS doesn't produce color from these images. Looks like it needs 16bit. Is that right?

The histogram in KStars appears to be OK, it's displays the image between min and max.

Yes, this is not actually an issue with the histogram, it is the initial stretch that kstars applies to all images. Basically it displays the images with the min values in the image being the position of the black point and the max values in the image being the position of the white point. I was actually going to mention this to Jasem. I had an issue with my Lunar Eclipse images because they all looked blown out in KStars when I was taking them, so I had to open them in PixInsight right away to see if they really were blown out, but they were actually pretty good. The initial min-max stretch is outstanding for taking nebula images because you can see the nebula right away, but it isn't very good for high contrast targets. I think we should add an option to display the images with zero being the black point and the maximum possible value being the white point, so that you can see the linear image instead of the stretched image if you like.

Thanks,

Rob

Yes, that's what I meant. Fits Viewer estimates MAX too low - there's information beyond MAX.
It cuts whites too aggressively.
Would be nice to have MIN/MAX adjustable and maybe with an option to have them fixed to 0-255.
Thanks!

We have a Google Summer of Code 2019 project to overhaul the FITS display... but unfortunately no students so far.

community.kde.org/GSoC/2019/Ideas#Projec...tometry_Improvements

Wow! Nice list of improvements. Hopefully someone would join.

But seriously. When I was using a DSLR, I relied on its internal histogram and it worked. Now I am 100% CCD/CMOS and rely on KStars/Ekos. And the histogram/image are wrong in Fits Viewer.
I have just a little above zero experience in programming, I have no idea how to do it in Linux, compile and such but I think if one changes the MAX value to threefold of what it is now for histogram/image (or better yet increase the MAX to the true max. 255 or whatever it is) - that would greatly improve the usability. Automatic contrast stretching is always bad...
Thanks!

You can do this now. Go to Settings --> Configure KStars --> FITS --> Autostretch. Turn that off, then you'll see the full range in the histogram.

The issue is that the autostretch _changes_ the data... I did this to save RAM since before it uses to create a buffer to do the autostretch... let me figure out a middle ground.

Yikes... I didn't know that. That's exactly what I need. Thank you so much!