I see that EKOS has the option to do unguided dithering, so I tried it last night.

1.  It worked, but seemed to only dither in one direction.  Is that normal?
2.  After dithering - it turned on my autoguider!  Is there a setting to stop that?  I didn't have the guided dither option turned on, as you cant turn on both guided and unguided dithering anyway.  But after it dithered - it went back and turned my autoguiding back on.    That shouldn't happen if I am using UNguided dithering.



 

I am also interested.

1. I experience the same behavior using 0.5s 0.3s pulses. My idea was to test using longer pulses like 1s.
2. It could be CEM driver related because 10micron doesn't show this issue.

Ferrante 

 

I am interested by the topic too! 

Thanks,
Maxime

Yes I noticed too that unguided dithering only happens in one direction. My object was quite rapidly disappearing from my frames since I was using quite a large dither step!

I tried to find a pattern so I integrated but not registered 120x180s frames with 0.3s dithering every frame (see attached image).
The dither pattern is not linear nor related to RA or DEC but definitely not random.
Btw the guide is not drifting: the arc is clearly made of point stars, eccentricity is around 0.3. 
Do you experience the same?

 
 

I also noted that non guided dithering happens more on one side than on the other. At the beginning I thought it was the mount drifting, but then I realized that such a drift over the small amount of time (10s) between exposures (30s) would result in extremely elongated stars, which is not the case. I have still to understand where the wrong guide pulse is generated, if in kstars or in the ioptron driver. I may be wrong, but I seem to remember that this behavior started when I updated my GEM45 to the v3 command set (which, by the way, introduces a new set of commands for guiding).

Nevertheless, I searched a bit in the forum, and found out that a similar behavior was seen also for guided dithering, and then Jaseem fixed the "random dithering not being not so random" (github.com/KDE/kstars/commit/6e4d0c91846...202a1ef28432c08de4fd). Maybe a similar fix is needed also for non guided dithering? I analyzed the logs, and even if on the long run the direction and amplitude of dithering are uniformly distributed, there are often sequences of 5-10 pulses with the same direction and almost same amplitude.