Problem(s) Encountered:

One anomaly that I don''t understand is that imaging with g, r, i filters required *very* different telescope focus, for example:

g  2684

r  2668

i  2678

This is not supposed to happen with OSMOS, and indeed I never noticed a significant difference before, e.g., when I used the same three filters in September 2016.

Maybe I will test V, R, I the next night for the same effect.

Solutions:

Not sure yet if this has been followed up on... .