A few months ago I purchased the iOptron CEM26 mount.
Things seems to work fine. Recently I started to observe significant oscillations of the guiding.
I’m using a 6’’ classic cassegrain as the main telescope and a 60mm/240mm guiding scope with ZWO ASI462 as the guiding camera (the problem exist with different rigs as well).
I control the system with ASIAIR (although the guiding issues exist also with phd2 on a laptop).
I use a very stable pier. The polar alignment is perfect (sub minute error in both axis). The focus is optimal. The weather is great (nice seeing and no wind)
The problem is that the guiding is poor with unexplained error peaks of 2,3,4 and even 8’’ once every minute or so. Even between such peaks the guiding is not as I expected.
I was wondering if anyone has a clue about the problem.
I attach picture of a guiding example (taken from phd2 log viewer).