My Star Test

I use a 90 mm refractor F10 and I tried a star test on Deneb at 120X's. The
outside of focus did not look at all like the inside of focus. The inside
focus had 3 or 4 concentric rings of equal low intensity brightness then an
outer ring that was fuzzy and brightest. The outside focus had what looked
like a blueish solid inner low intensity area followed by a space then a
ring then another outer ring that was brightest and fuzzy.

Just what does that mean? The seeing was maybe magnitude 4 with ho hum
transparency. The moon had a significant glow around it that extended a
distance.

MT