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INDI Library v1.9.9 Released (30 Nov 2022)

Bi-monthly INDI Library released with new drivers and bug fixes.

FITS pictures appear to be red channel only

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Hi,
I would say that I am an ardent Linux user (5+ years), I have also been a raspberry pi user off and on for as long.
I wanted to find a way to do astro photography a year ago and was VERY HAPPY to find kstars / ekos / indilib as a way of doing that.
THANKS VERY MUCH for creating this platform, REALLY, SERIOUSLY. I have watched many of Jason's UTube videos, THANKS
VERY MUCH for those.
Apologies if this is the wrong place to post or this question has been asked and or answered, I am brand new to this forum.
I set up my own raspberry pi about a year ago with indilib 1.8.3, indi-bin reports as 1.8.4. I have been running an asi294MC color camera
and an ioptron CEM60EC connected to it. My laptop runs linuxmint 18 (cinnamon, not kde) and I have kstars/ekos installed there.
I have astrometry.net installed and working on the laptop, I can connect everything up AND IT ALL WORKS! I can capture images.
It has been an uphill climb. I only recently found out that the icons in the menu bar do not show up in kstars or the fits viewer and when I
corrected that to show text, I found out that the fits viewer had a histogram feature I did not know about, and when I looked at that, I
found that it only shows me red channel data, green and blue are zero. I have only shot about 20 or so pictures over the last year and
they all looked sort of black and white and I did not know why. The histogram seems to confirm this in showing only a red channel.
I have looked at many of the pictures I have taken, and they all show red channel only histograms, the header info does show a
bayer pattern of rggb, so something might think it was a color shot at some point.
I do not have a filter wheel, that is set to nothing. I do not know see any way in the ekos capture module to identify the capture as being
from a color camera, so I assumed this was inherently done somehow. I have turned off debayering in the preview fit configuration info.
I am confused now. I am will to do any logging if that is desired. Is there any place else to set something? HELP !!!
Thanks for your attention.
2 years 3 months ago #59563

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Hi and welcome to INDI forums! Can you post a link to one of these FITS files?
Jasem Mutlaq
Support INDI & Ekos; Get StellarMate Astrophotography Gadget.
How to Submit Logs when you have problems?
Add your observatory info
2 years 3 months ago #59572

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Hi,
Thanks for your attention. I did not mention that I have been doing visual astronomy for ~ 20 years at this point, but astrophotography is relatively quite new (~ 1 year +). So I am still learning many things. I have had many issues with setting up the scope and photography platform and learning to operate it. So I have not spent much time at all on the results end and the post picture processing side of this.

So I am really not familiar with all the abilities of the FITS viewer and stumbled into them very recently, like I said. My opinion of the FITS format has gone up considerably in the last week or so and I really appreciate that kstars / ekos seems to be doing a serious job filling out the header information. And I do appreciate the histogram functions, but I still need some more explanation of that.

So when I saw the single channel output and noted it was red only, I thought there was a problem. After looking at it and working with it more, I understand now and it makes sense that the capture process would create a single channel picture with all the data in that one array. The debayer pattern is there and shows rggb and I can now see that when I invoke debayering in the view (one way or another) the viewer then shows me all 3 channels like I would expect. So I think everything works, and I understand more now. So I won't post a picture, because I do think everything is normal and expected now. I am still confused about the histogram. This may be partly because I have seen and worked with the asi-air product (my astro friend has and uses several of them) and their histogram, in which you can stretch and restrict the color frequency range of the preview picture before you save it. He manages to take relatively great pictures, preview only, and frequently skips the whole stacking / picture post processing stuff. And yes, He has spent a lot of money on his platform to be able to do that.

I prefer your approach because it really supports Linux, supports many vendors cameras, and I very much like having full access to the raspberry pi, which asi-air does not allow. I believe that your FITS viewer histogram shows intensity along the bottom of the graph and since my camera is doing 14 bit a2d conversion (0-15k) I can see essentially how much signal I captured in the picture, allowing me to decide if I could capture longer or if I am reaching saturation.

The frequency on the left side is the one I don't really understand. I generally see (after debayering) all three channels spanning the frequency range to similar but differing amounts. I know that r g and b have specific and separated frequency ranges and the bayer filter inside my color camera restricts the specific pixels to those ranges. So I think the frequency scale you show on the left side is some other kind frequency and since its units are not really disclosed, I'm not sure what we are trying to tell me about frequency.
Please let me know what you think about the histogram and frequency.
Thanks VERY much!
Last edit: 2 years 2 months ago by Jasem Mutlaq.
2 years 2 months ago #59663

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