Here are my notes from viewing Mars last night in a small 120/900 refractor. It really is the best opposition I have ever seen. I tried all my filters, including nebula filters. Oddly enough, some deep sky brought out details. I found the older OIII and UHC to be more effective than the newer versions. Overall, it's hard to beat the view without filters.
(Planet in Pisces)
Observed: Oct 22, 2020 at 9:55:37 PM
Comment: Once again Mars looked wonderful tonight, but not comparable to
how it looks in the 16".
The tiny but bright white polar cap stood out. The best view was with
the 5mm Pentax at 180x. I tried all my color filters and nebula filters
but still prefer the view with no filter. I like red Wratten 25 for
surface detail. The Tele Vue Mars A and the Vernonscope Wratten 85
Salmon are very close. Oddly I also liked the old Lumicon OIII & UHC
(older "red" version) and the Orion UltraBlock. My camera ND 0.3 was
also very satisfying. The Vernonscope polarizer looked very similar to
no filter, only dimmer. That might be an ideal filter in a large
telescope, but not the 120mm.