Requirement to configure the "Guide Via" parameter in the optical train for unguided dithering is neither documented nor obvious.
I'm shooting unguided in Ekos and wanted to start using unguided dithering. Not having a guide camera, I read only the paragraph on unguided dithering in the Dithering section in the docs. But it always failed, logging "Warning: Dithering failed".
After much searching on the web, hair-pulling and also starting to look into how to debug Ekos, I've found this remark on the INDI forum, particularly saying
you still have to make an optical train where you select your mount as 'guider'. In the Ekos Guiding tab you then select that optical train.
(It also mentions that there were several other people with this problem and solution.)
I did this, and it finally worked!
I see that in the Setup section in the docs, it says
The Guide Via should be your mount, assuming you are sending guide pulses directly to your mount, or the name of the ST4 device (e.g. your camera) should you be using ST4 guide pulses.
I also see that in the implementation, a dither pulse might be regarded the same as a guide pulse; however, not having a guider and not being very familiar how guiding works, this was not obvious to me.
I'd therefore suggest to
- Add a remark for the need to configure the "Guide Via" parameter in the optical train to the tooltip and the documentation of the unguided dithering option.
- Add the reason why dithering failed (in this case a missing "Guide Via" value) to the logged error message.