New coat ,Takahashi called multi-coat ,have good durability,from 1986 or7,no need for worry about humidity.
I am living in north Japan of Hokkaido,climate is better than Tokyo,except heavy snow.There's no sign of cloudy in about 30years.
Here's my FCT-100 set on a genuine pillar.
I remember of summer in'87 first light of jupitor by FCT-100 ,so crips image.Incredible detailed image for diameter 4 inch,I could not sketch,220x ,with eyepiece Hi-OR 2.8mm.I wish I cloud pushed more high magnificasion. In the next time, shot saturn with NikonF2 very long time exposure of 30 seconds.That photo,selected the magazine 'Tenmon guide' readers photo,was best image of 4inch and more like 8inch reflecter at that time.