Many of us live in regions where pure clear skies are so rare that we would like to run astrophotography sessions although the sky is partially clouded. KStars / EKOS has meanwhile several robustness features that make it possible to run a fully automated session although the sky is not perfect.Since this question arises in this forum from time to time, this thread is intended to bundle all tips and tricks to make the session as robust as possible.
It does not matter how clouded the sky is as long as the small fraction of the sky you are capturing is clear. So the best approximation that capturing does not make sense is when guiding runs into problems with the guiding star. If there are clouds that are so heavy that guiding get's into trouble, the captured frame is worthless.
If a guiding problem is detected, the best reaction is to immediately abort capturing. You can control this with the following parameters:
- Guiding options | Guide | Lost star timeout
If the guiding star is lost for this period of time, guiding aborts and subsequently capturing aborts. A typical value is 20 seconds.
- Capture | Guide Limits | Abort if Guiding DeviationIt might happen that the guide star re-appears, but your scope is already to far off so that continuing would create elongated stars
If you are using the Capture module standalone without the Scheduler, capturing will recover as soon as the guiding deviation is below the configured value. If this is unchecked, capturing will remain aborted.A more robust way for recovery is using the Scheduler. Its main feature is the "Aborted Job Management" that gives you the opportunity to try to restart capturing. There are two options that should be used, depending on the expected scenario:
- Aborted Job Management | Immediate
This is the option that I prefer. If a job aborts due to guiding problems and restarting guiding fails for 5 times, the Scheduler sets the job state to ABORTED and will retry to start it after the configured amount of time. This will happen as long as the constraints of the job remain valid.
- Aborted Job Management | Queue
Similar to 1., but the Scheduler will jump to the next scheduled job and tries to start this one. This variant makes sense if you expect that the clouds remain in a certain part of the sky and starting the other job increases the chances to find some clear sky. From my experience, that does not happen very often and it's better to stay a a certain target.
That's it, hope that helps, feedback warmly welcome.
p.s.: Don't forget, this is not
an approach for nights where the clouds are so heavy that rain is at risk. In this case, you additionally need safeguard measures for your observatory, which is not issue of this thread.