Welcome, Guest
Username: Password: Remember me
20 Aug 2017
INDI development team is happy to announce the release of INDI Library v1.5.0. This new exciting release builds on the maturity of INDI Library and comes with many new supported devices and fixes for existing drivers.
Read More...
  • Page:
  • 1

TOPIC: Flat Calibration failing to find a valid exposure time

Flat Calibration failing to find a valid exposure time 1 month 1 day ago #19500

I have a 2-3 day old version of Ekos running on a Raspberry Pi 3 under Ubuntu Mate and controlling a QSI 583 camera.

After imaging last night I set up a run for flats using the camera control module, setting 1 second as a starting point for the LRGB filters and a target of 40,000. It started doing test shots, gradually decreasing the exposure time (for the R filter if I recall but it could have been L) but after a number of attempts it jumped the time up above 1 second and starting looping doing this dropping the time and then jumping back up.

I decided to redo it, starting the exposure times at 0.05 and that worked for the RGB but failed on the L, where it kept on trying the same exposure time repeatedly. I ended up estimating what the exposure should have been and it worked fine.

I had to shut everything down to return home and I was unable to copy and paste the feedback as displayed at the bottom of the window. If this is logged somewhere please let me know and I will include it as an attachment. I realise now I should have taken a screen shot.

I have used the flats calibration before, but not in the last couple of months, and have not previously had any issues.

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

Last Edit: by phomer60. Reason: Grammar correction

Flat Calibration failing to find a valid exposure time 3 weeks 4 days ago #19772

I have performed some additional testing and things have improved after bringing the software up-to-date, however, I still have some issues.

I set up a sequence queue for LRGB starting each exposure at 1 second with a target of 40,000 and a tolerance of 1,000.

This time it processed the LRG but got into a repeating loop for the B(lue), which appears to be infinite, as seen in the attached text file.
Attachments:

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

Last Edit: by phomer60.

Flat Calibration failing to find a valid exposure time 1 week 2 days ago #20053

After considerable testing I was able to determine that the algorithm has some issues if it takes to many attempts to find a solution. The most common issue was it got into a resonance loop attempting to solve becuase it couldn't get to the tolerance. A second issue was that the time second was only accurate within 0.01 seconds but it would try more accurate attempts and then find there was no change and must go into a recovery mode where it makes a significant change, once it jumped from 0.4 to 3600 seconds.
There are two things that ended up working around the issues;
1) I relaxed the tolerance from 1,000 to 5,000.
2) I set the initial time to 0.2 seconds instead of the recommended 1 second.
The following user(s) said Thank You: xsnrg

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

Flat Calibration failing to find a valid exposure time 1 week 2 days ago #20060

  • xsnrg
  • xsnrg's Avatar
  • Offline
  • Expert Boarder
  • Expert Boarder
  • Posts: 110
  • Karma: 2
  • Thank you received: 13
This is the behaviour I has seen as well. It does not happen often, but when it does, it does not recover.

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

Flat Calibration failing to find a valid exposure time 1 week 1 day ago #20081

Are you being a little too optimistic to reach 40,000 ADU on a flat? (I presume you are going for low gain). Can I suggest you review test histograms at 10,000 - 30,000 ADU. Tolerance of +/- 500 should be fine when you get your ADU target. You can easily take more images if you're worried about getting enough signal.

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

Skywatcher 190MN - EQ6 Pro - ASI1600MM-Cooled - EFW7 - ASI120MM - WO f4 Guide Scope - Rigel nStep - Ekos chained to two Raspberry Pi 3's - KDE Neon - PixInsight

Flat Calibration failing to find a valid exposure time 1 week 1 day ago #20088

I'm really not sure what you mean by being optimistic, 40,000 out of 64,000 is a fairly reasonable value. Setting the tolerance too tightly is the main issue as the camera cannot make the small exposure adjustments to reach an acceptable figure. This is only an issue with a fairly bright lightbox as the minimum adjustment can end up being more than the tolerance. This problem still occurs if I choose 10,000 to 30,000 but I find the results are not as good.

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

  • Page:
  • 1
Time to create page: 0.368 seconds

Login

1. 3rd Party

Choose from the numerous 3rd party INDI drivers to suit your needs!

1. Got Problem?

Check out the FAQ, the forum, and the bug tracking system to resolve any issues you might have!
You can also subscribe to INDI newsletter and development mailing lists to get the latest updates on INDI!


Gallery

Replica

Why INDI

Replica