What to do with a cold scope and EP's?

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.

"david johanson" wrote in message
...
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...

If the lenses are dry, cap everything before bringing it from cold to heat.
If they are already wet, bring them in, let them dry, and then cap them.

How dangerous is moisture/condensation to all of this?

Moisture will draw in particulates from the air and form deposits on the
glass. If you cap the lenses before bringing them in, they should remain dry
as they warm up.

No matter what you do, eventually the eyepiece lenses will need cleaning
from normal use. However, the scope lens will pretty much only need cleaning
if it gets wet, or if dust has become noticeable and bothersome. The more
you do to prevent mositure from forming on glass, the cleaner your optics.

Stephen Paul
Shirley, MA

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.

Everything was quite wet when I packed up. A frost had formed as the air
cooled, my truck took a long while to defrost before I could head home.
(I had left the doors open with the radio on.) I have a feeling that
this will be a constant battle for me. Thanks for the advice.

Larry G wrote:
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.

Should I do anything special to the scope and eyepieces
when I bring them into the house?
How dangerous is moisture/condensation to all of this?

Tips for storage and dealing with dew:
http://www.wwnorton.com/astro21/sandt/dew.html

The eyepieces are uncapped and under a loose cover to keep dust
away...
How dangerous is moisture/condensation to all of this?


Hi:


The bottom line is, "never cover a scope or eyepiece that has condensation on
it.

--If there's condensation on the scope's corrector or eyepieces while you're
outside, leave the covers off, bring them in, and let the moisture evaporate
before you put the covers on.

--If there's no moisture on the corrector or your eyepieces while you are
outside, go ahead and cover 'em. Any moisture that condenses inside will be on
the covers, not on the corrector or eyepiece lenses.

Peace,
Rod Mollise
Author of _Choosing and Using a Schmidt Cassegrain Telescope_
Like SCTs and MCTs?
Check-out sct-user, the mailing list for CAT fanciers!
Goto http://members.aol.com/RMOLLISE/index.html

david johanson wrote in message ...
snip My question: Should I do anything special to the scope and
eyepieces
when I bring them into the house?

Not the best solution, but what I do for eyepieces when observing in
mountains of Intermountain West at 20-30 degrees, where the dew
freezes as an ice layer on lenses, is the following:

1) A piece of heavy felt to cover the lens box.
2) A $12 el-cheapo automobile heater/fan - the kind you plug into a
cigarette lighter. Buy at any chain auto parts store.
3) A portable car restarter battery with 12V cigarette lighter power
ports built-in. Buy at any chain auto parts store.

I leave the felt over the lens box and ontop of the heater/blower,
generally keeping the heater/blower on "fan" only. The slight breeze
keeps the dew/ice from forming. It reduces the amount of moisture that
condenses on the lenses as I drive down the mountain to lower and
warmer altitudes. It's a simple matter to reach under or flip-up the
felt cloth to replace and retrieve lenses.

Not prefect, but the best I have come up with to date. One drawback is
the annoying noise that the el-cheap heater/blower makes.

- Canopus

Things cant draw particulates if you cover with a ventilated rag
like cheeseclothe. Its not a good idea to cap cold eyepieces.
Simply throw a rag over them and let them warm up. Pull the
rag off once warmed, let stand for a minute, then cap.

M.




Stephen Paul wrote:

"david johanson" wrote in message
...
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...

If the lenses are dry, cap everything before bringing it from cold to heat.
If they are already wet, bring them in, let them dry, and then cap them.

How dangerous is moisture/condensation to all of this?

Moisture will draw in particulates from the air and form deposits on the
glass. If you cap the lenses before bringing them in, they should remain dry
as they warm up.

No matter what you do, eventually the eyepiece lenses will need cleaning
from normal use. However, the scope lens will pretty much only need cleaning
if it gets wet, or if dust has become noticeable and bothersome. The more
you do to prevent mositure from forming on glass, the cleaner your optics.

Stephen Paul
Shirley, MA

Try cheeseclothe instead of felt.



Canopus wrote:

david johanson wrote in message ...
snip My question: Should I do anything special to the scope and
eyepieces
when I bring them into the house?

Not the best solution, but what I do for eyepieces when observing in
mountains of Intermountain West at 20-30 degrees, where the dew
freezes as an ice layer on lenses, is the following:

1) A piece of heavy felt to cover the lens box.
2) A $12 el-cheapo automobile heater/fan - the kind you plug into a
cigarette lighter. Buy at any chain auto parts store.
3) A portable car restarter battery with 12V cigarette lighter power
ports built-in. Buy at any chain auto parts store.

I leave the felt over the lens box and ontop of the heater/blower,
generally keeping the heater/blower on "fan" only. The slight breeze
keeps the dew/ice from forming. It reduces the amount of moisture that
condenses on the lenses as I drive down the mountain to lower and
warmer altitudes. It's a simple matter to reach under or flip-up the
felt cloth to replace and retrieve lenses.

Not prefect, but the best I have come up with to date. One drawback is
the annoying noise that the el-cheap heater/blower makes.

- Canopus