×

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

Bi-monthly release with minor bug fixes and improvements

Re-alignment in Scheduler - is it possible?

  • Posts: 992
  • Thank you received: 155
I've noticed this for the last two years. It used to be worse, where I needed to re-align after 20 or 30 frames.
Now I still need two after 60-80 frames. The drift is certainly there (with as low as 2 pixel dithering every 4 exposures).
I currently use a wide FOV (348mm F/L) but I know once I jump to a narrow FOV this will be a serious issue.

Peter
3 years 11 months ago #52803

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

  • Posts: 1957
  • Thank you received: 420
I don't think this is possible at the moment. One workaround could be to schedule "short" jobs (that would take N frames) and then schedule another job for the same target and make sure that "align" is enabled. You may need to fiddle with the scheduler configuration (both in the scheduler tab in Ekos and the settings in the Ekos tab in the KStars config screen) for the scheduler to accept the individual jobs and not to collect them together in one big job. It probably will warn you that you are targeting the same object and such but I think if you do this properly then it will accept the jobs and will realign in between jobs. If not then you could try to schedule a single 10 sec job of a star nearby so the telescope will slew There And Back Again (sorry for the The Hobbit reference) and realign on your target when it has slewed back.


HTH, Wouter
3 years 11 months ago #52817

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

  • Posts: 10
  • Thank you received: 3
Yeah, I did not find a way.

Queuing the same job multiple times seems to mark the following jobs as "Invalid". Running the same job in a loop does not run the alignment every time the job runs which of course makes sense most of the time when you have a sequence like 1xR, 1xG, 1xB frames and you just want to repeat that. I don't think looping multiple jobs (1,2,3 -> 1,2,3...) is supported either, so taking a "garbage frame" in between as a job to force alignment wouldn't work either.
The problem does indeed get quite apparent when dealing with a smaller field of view and seems to be even worse when there are issues with seeing. It's currently not a deal breaker but being able to re-center would be ideal, since my sessions are often hands-off once I've set up the scheduler.

Thinking feature wise, perhaps it would make sense to have an option to run the solver every N frames to see if the centering is still within limits - if not, it would run a re-center.
3 years 11 months ago #52832

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

  • Posts: 535
  • Thank you received: 109
Is this due to dithering? Does it only go in one direction as that would make sense because of backlash considerations? I guess even though I use it, I never stopped to look and see if that was the case. Most of my capture sessions are around an hour each so I have not noticed drift much.
3 years 11 months ago #52833

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

  • Posts: 437
  • Thank you received: 31
Robusto,

What are you using for guiding?

Paul
3 years 10 months ago #53019

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

  • Posts: 10
  • Thank you received: 3
phomer60,

I'm using PHD2. No issues there.
This isn't game breaking, but I'd re-center if I could. There's about 110 arcsec drift I think from the start to the end of the session. Attached an image to show the amount.

I realize a feature like this would touch a lot of internals of Ekos and I'm not sure if it's worth the effort in the end though, unless there are a lot of others that feel that this would be a much needed feature.

3 years 10 months ago #53080
Attachments:

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

  • Posts: 309
  • Thank you received: 40
I'm seeing the same sort of thing... I even added a Wish List item: Drift Limit

I also added a video of the drift by clicking the "Recent Images: Drifting Video
This was apart of another thread I started related to this whole thing (at first I thought it was due to something after the flip, but that's not the case)

Jasem sent a link on that thread to the code. Very cool, BTW. My only thought was maybe the random value is just returning the same direction too many times.
The only thought I have is instead of doing random dithers, do a fixed right/right/left/left... left/left/right/right... up/up/down/down... down/down/up/up. Do a cross shape, always return to the center.

In the mean time, I turn on the cross-hairs and when I check in and see it too far away from center, I stop and re-align.
Last edit: 3 years 10 months ago by David Tate.
3 years 10 months ago #53082

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

  • Posts: 163
  • Thank you received: 26
In principle it shouldn't drift away if you are using guiding, right??
3 years 10 months ago #53083

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

  • Posts: 309
  • Thank you received: 40
As I understand it, the dither does a drift on purpose a set number of pixels. The guide star is re-acquired and your ready for the next image.
The guiding is while you're imaging. The drift during dither is between images.

So just for argument... that alignment star can move (while dithering, one image at a time) all the way across your guide scope's field of vision, until it's gone... then your guiding would stop. IMHO
Last edit: 3 years 10 months ago by David Tate.
3 years 10 months ago #53084

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

  • Posts: 10
  • Thank you received: 3
Oh and also, I'm currently not using dithering (I don't need to since there's drift this big ;)
3 years 10 months ago #53086

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

  • Posts: 163
  • Thank you received: 26
Edit: Nothing, forget it :)
Last edit: 3 years 10 months ago by Bart.
3 years 10 months ago #53088

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

  • Posts: 309
  • Thank you received: 40

But dithering is pretty important to be able to remove hot pixels and such.
3 years 10 months ago #53093

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

Time to create page: 1.004 seconds