On Tue, 23 Nov 2004 23:49:53 -0500, david johanson
wrote:

Had a nice outing with my little, new-to-me Celestron C90. Nice views of
Saturn around 9:15 or so, fighting the moonshine. Spent a long while with
a 15mm and 9mm eyepieces and had 15 or 20 seconds of spectacular viewing
with the 6mm. Enjoyed the moon for a long while, even took a couple of
pictures with an ancient Canon FTb and some B+W film that my son was
using in his photography class. He'll be surprized when he develops them!
Lots of fun until a coyote howled nearby and I decided to pack it in.(I
was about a 1/4 mile off the road in a clearcut-thanks for the 4-wheel
drive!)

Anyway, I live in Midcoast Maine and it was about 28 degrees when I
packed up and headed home.
My question: Should I do anything special to the scope and eyepieces when
I bring them into the house? I have the scope with the diagonal in facing
down and the lens cover off but a dust cover over the whole scope. The
eyepieces are uncapped and under a loose cover to keep dust away...
How dangerous is moisture/condensation to all of this?

Never really crossed my mind until I walked into the house.

Moisture can be a problem on a few fronts:
1. It collects dust onto the optical surfaces
2. It can promote mold and mildew
3. It may affect the longevity of optical coatings

Few of these problems are likely to occur over-night, but
some simple precautions will help avoid them altogether.
Place the eyepieces in air-tight containers and cover the
end and holes of the optical tube assembly, before coming
indoors. Warm moist air may condense on the outside, but
the cooler air will warm up, lowering the humidity and reducing
the chance of condensation on optical surfaces.

Cheers,
Larry G.