×

INDI Library v1.9.6 Released (21 May 2022)

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

Trying To Understand FITS Files From SVBONY SV305 Pro Camera

  • Posts: 124
  • Thank you received: 5
OK, so I got Ekos to record data from my SV305 Pro camera again, but running some tests, I get some crazy looking data, and I'm not sure what to think of it.

This started when I was curious as to whether I should adjust RGB channel gain settings to adjust the color balance that comes out of FITS files, which are always predominately green-yellow.

So below first are 2 screen grab images are from AstroDMX, first the image as it first appears onscreen when I connect the camera, the second is a color corrected image using the "one touch" auto color correction button in AstroDMX. This color chart is being lit by 5000k lights. As you can see, AstroDMX applied R and B bias adjustments to balance out the color. This was the premise I thought I may apply to the the R and G gain settings in the INDI control panel for the SV305 Pro for color balance. So I decided to take some tests first with the Ekos default values for the SV305 Pro, and what I got throws me for a loop. These images are saved out as JPEGs from the ASI FITS Viewer app in Windows.
So the first set is:
5 second exposure no gain auto debayer (KStars)
5 second exposure no gain no debayer
5 second exposure 50 gain no debayer
Than, being as this is primarily an planetary camera, I tried a:
.01 second exposure 100 gain no debayer
And then finally I turned off the room lights and tried to emulate a DSO sub at:
30 second exposure no gain no debayer
So the $64,000 question is; Is this normal? Besides planetary imaging with AstroDMX, I want to experiment with the camera for some DSO work, and the long exposure shot at zero gain gives me hope LOL. However, what's going on with all those other shorter exposure shots? Looking at the 30 second exposure, it appears I don't need to adjust the R and B channel gain setting in the INDI control panel and can just leave them alone.

Working with FITS files is a new territory for me, so I don't really understand why I'm seeing what I'm seeing here, and for DSO work it appears as tho I don't really have to worry about it and just shoot at whatever exposure I may need for a given target. But any insight on why this stuff looks like it does is appreciated.
Thanks.







The following user(s) said Thank You: R Dan Nafe
1 month 3 weeks ago #82805
Attachments:

Please Log in or Create an account to join the conversation.

  • Posts: 66
  • Thank you received: 22
This is likely normal/expected behavior. You are effectively viewing the raw data in the fits file. Most color cameras these days have two green pixels for every red and blue in the bayer matrix. This tends to bias the color of the image toward green.
1 month 3 weeks ago #82807

Please Log in or Create an account to join the conversation.

  • Posts: 124
  • Thank you received: 5
Well yes I know the RGGB array (or GRBG, as it is in the IMX290 sensor), but it's the bizarre posterization that I was really referring to. As I mentioned, working with FITS is new territory for me, so when I see stuff like this, I'm not sure what to think of it.
Last edit: 1 month 3 weeks ago by Phil.
1 month 3 weeks ago #82808

Please Log in or Create an account to join the conversation.

  • Posts: 66
  • Thank you received: 5
There are some settings in astrodmx to colour areas to show they are saturated. Doesn’t quite explain things to me but might be worth checking.

I’m also having problems understanding fits files. I thought they were just the raw files wrapped with details about where they are pointing etc but I see weird colours (if I’m lucky to see colours though that could be down to my doing short exposures due to problems..)and things like cross hatching which make it impossible to view the image no matter whether debayering is on or off. This seems to happen with my sv305 and sony a7rii dslr.
1 month 3 weeks ago #82811

Please Log in or Create an account to join the conversation.

  • Posts: 66
  • Thank you received: 5
There are some settings in astrodmx to colour areas to show they are saturated. Doesn’t quite explain things to me but might be worth checking.

I’m also having problems understanding fits files. I thought they were just the raw files wrapped with details about where they are pointing etc but I see weird colours (if I’m lucky to see colours though that could be down to my doing short exposures due to problems..)and things like cross hatching which make it impossible to view the image no matter whether debayering is on or off. This seems to happen with my sv305 and sony a7rii dslr.
1 month 3 weeks ago #82812

Please Log in or Create an account to join the conversation.

  • Posts: 124
  • Thank you received: 5
Yeah, dunno know what to think of it. Fortunately AstroDMX will be an effective planetary app when I finally get around to shooting planets, and the long exposure simulation from Ekos rendered well enough to make me think it's not going to be an issue for low res DSO shooting.
The following user(s) said Thank You: R Dan Nafe
1 month 3 weeks ago #82819

Please Log in or Create an account to join the conversation.

Time to create page: 0.546 seconds