×

INDI Library v2.0.6 is Released (02 Feb 2024)

Bi-monthly release with minor bug fixes and improvements

Guide camera darks seem confused

  • Posts: 200
  • Thank you received: 18
I have found that using a dark library with my guide camera has a noticeable positive benefit in terms of SNR and guiding rms when I combine it with IR guiding.  I have recently changed from an rPi to Ubuntu on a mini pc and also upgraded to kstars 3.5.4 and now it seems to be messing up somehow.  The dark background subtracted images are visibly worse than when I leave darks unchecked.  I have cleared and redone the dark library multiple times.  It does seem to be getting settings like gain (which I have to turn up due to IR filter) confused between the guide camera and prior settings in the imaging panel for my main camera.  There isn’t a way to set gain when you setup the dark acquisition sequence so I can’t seem to force it to use the right values.  I one occasion the guide camera setting for pixel width and height got transposed to the telescope camera - it seems like there is some kind of crosstalk?

I am using a ZWO ASI290mm mini guide camera and a QHY600PH telescope camera.
Last edit: 2 years 6 months ago by Thomas Mason.
2 years 6 months ago #75446

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

  • Posts: 985
  • Thank you received: 161
I can't contribute anything to the crosstalk issue but you wrote "There isn’t a way to set gain when you setup the dark acquisition sequence so I can’t seem to force it to use the right values."

You could try to set gain in *Indi* guide camera settings immediately before taking darks.
2 years 6 months ago #75448

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

  • Posts: 200
  • Thank you received: 18
I did try setting gain in the indi panel but it seems to get overridden from elsewhere - I think from whatever is in the camera panel.  I think a setting in the Dark Library acquisition window where you set the times, binning etc would be a good addition.
Last edit: 2 years 6 months ago by Thomas Mason.
2 years 6 months ago #75449

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

  • Posts: 25
  • Thank you received: 15
This interesting. I experienced a similar issue while using the dark library, but with the alignment images. A large horizontal band in the image appeared completely black after the dark was substracted, as if the dark in the library had become corrupted. I had not changed anything in camera settings (nor in ekos nor directly in the indi control panel).

I was able to fix it by redoing the dark library, but i'm worried it might happen again while unattended.

Not related to the issue but related to the new dark library management: I noticed that the script that takes the darks to populate the library also changes the capture storing path and unchecks the option to display captured images in fits viewer but sometimes it does not revert these options to their previous states (found out after a long time wondering where my captures were and why they were not being displayed...). Could it be that unintentionally storing my captures there corrupted the library?

RIcardo
The following user(s) said Thank You: Alfred
2 years 6 months ago #75454

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

  • Posts: 225
  • Thank you received: 16
Ricardo,

Did your alignment screen look like the attached image? This happened to me for the first time after upgrading to 3.5.4.

Ron
Last edit: 2 years 6 months ago by Ron Clanton.
2 years 6 months ago #75458
Attachments:

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

  • Posts: 1009
  • Thank you received: 133
Looking at the database (userdb.sqlite), the darkframes don't even have an entry for the gain.  :o So it seems we're stuck with only one gain there?
As for setting it - have you tried (in capture tab) to select the guide camera, enter a gain/offset in the respective tabs, and take a single preview before running the dark library sequence?
 
2 years 6 months ago #75460

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

  • Posts: 200
  • Thank you received: 18
I did exactly this and it took darks with the correct gain but the dark corrected frames were still messed up - I did get one good guiding run but when I stopped it and restarted it was messed up as well. 

I have also observed the alignment messing up as described by Ricardo.  In that instance restarting ekos seemed to fix it.
2 years 6 months ago #75464

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

  • Posts: 25
  • Thank you received: 15
Hi Ron,
Yes, exactly like that, except for the position and extension of the blacked area (the whole lower half in my case).
I'm also using v. 3.5.4

Ricardo
2 years 6 months ago #75495

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

  • Posts: 225
  • Thank you received: 16
Interesting... I had assumed that I have a connection problem, but maybe not. I'm going to give 3.5.5 beta a shot... but if it continues to give me issues, I'll revert to my 3.5.3 stable.

Ron
2 years 6 months ago #75496

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

  • Posts: 200
  • Thank you received: 18
In an effort to reduce the number of variables I removed all prior darks from the dark library folder (simply clearing in ekos didn't get them all so I used the file manager to make sure it was empty).  Then I did a single exposure in the camera panel setting the gain and offset and using the 0.5s time I guide with.  Then I went into the dark library and created a dark for the single 1x1 bin and 0.5 seconds verifying in the control panel it was using the right gain and offset.  This resulted in a single master dark that looked as I would expect it to.  If I went into the guideing panel it seemed initially to correctly subtract from the light but after first couple of shots it started to result in images that were extremely noisy, far more so than when I did not enable dark.  It was not able to locate stars for guiding stably using the dark option.
2 years 6 months ago #75540

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

The noise is a stretching artificial. I verified this works as expected, at least for single-channel images.
2 years 6 months ago #75541

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

  • Posts: 200
  • Thank you received: 18
is there a reason why it would be worse at finding and keeping stars for multi star SEP when dark is used?
2 years 6 months ago #75565

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

Time to create page: 0.452 seconds