Eyepieces and cold weather observing.

During cold weather observing, is it better to keep your eyepieces warm
(e.g., by keeping them in your pocket) so the heat from your face
doesn't fog them, or let them equilibrate to the air temperature as the
rest of the scope does? I have only a few (Plossls, not those monster
big ones like Naglers -- not that they aren't on my wish list) so a
coat pocket could be an an option for me.

Nick

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Nick Theodorakis

contact form:
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On 2006-10-16 10:51 +0900, Nick Theodorakis wrote:
During cold weather observing, is it better to keep your eyepieces warm
(e.g., by keeping them in your pocket) so the heat from your face
doesn't fog them, or let them equilibrate to the air temperature as the

I prefer to keep them warm. They have less of a tendency to fog up on
nights where dew is collecting.

rest of the scope does? I have only a few (Plossls, not those monster
big ones like Naglers -- not that they aren't on my wish list) so a
coat pocket could be an an option for me.

That's how I do it.

trane
--
/////////////////////////////////////////////////////////
// Trane Francks Tokyo, Japan
// Practice random kindness and senseless acts of beauty.

A friend made a nice "eyepiece warmer" from a small cooler. He made a
plexiglass eyepiece caddy, faintly illuminated from the back by a red light.
Before putting the caddy and eyepieces in, he adds a microwavable hot pack
to the bottom of the cooler. It works extremely well.

Clear skies, Alan

Trane Francks wrote:
On 2006-10-16 10:51 +0900, Nick Theodorakis wrote:

During cold weather observing, is it better to keep your eyepieces warm
(e.g., by keeping them in your pocket) so the heat from your face
doesn't fog them, or let them equilibrate to the air temperature as the


I prefer to keep them warm. They have less of a tendency to fog up on
nights where dew is collecting.

rest of the scope does? I have only a few (Plossls, not those monster
big ones like Naglers -- not that they aren't on my wish list) so a
coat pocket could be an an option for me.


That's how I do it.

Same here. Don't want my cornea sticking to a cold eyepiece.
;-( -- pun intended


Shawn

Heat is more effective than non-heat methods; and to the best of my
knowledge and experience the small amounts of heat needed will have no
adverse effects on image quality.

On nights when condensation is expected to be a problem I keep all
eyepieces other than one I'm looking through capped and inside a
closed box. This keeps them condensation-free -- at least until
they're taken out and used ;-)

Usually (but not always) heat from my eye and/or face is sufficient to
keep the eyepiece that's being used free from condensation. (Facial
hair *might* play a role in the success of this method -- perhaps by
trapping moisture before it can reach the eyepiece's eye lens.) If I
leave the scope for any length of time I cap the eyepiece.

The above simple and inexpensive measures work for me, in my semi-arid
climate, most of the time. Only when it becomes evident that the
above measures will not suffice do I break out a Kendrick eyepiece
heater -- a wrap-around heated collar. This 'last resort' method has
always worked for me. Unfortunately it's a solution that comes at a
price: the heating strip(s), a control unit, and a power supply.

Willie R. Meghar
Observational Notes at:
http://meghar.blogspot.com/

Willie R. Meghar wrote:

On nights when condensation is expected to be a problem I keep all
eyepieces other than one I'm looking through capped and inside a
closed box. This keeps them condensation-free -- at least until
they're taken out and used ;-)


I use an eyepiece belt system with Tamrac lens cases...Modular
accessories(MAS):

http://www.tamrac.com/welcome.htm

The MX 5375 is fine for smaller eyepieces but use the MX 5378 for
Naglers. These cases hold eyepieces securely and have zippered top flap
that keep them dust free and warm in winter. I keep 4 cases on belt so
can quickly change out EP. This is esp. nice if you ever have to
observe from ladder.

Paul

I keep a couple of eyepieces in my pockets, and one in the scope. Every
time I switch eyepieces, the cold one gets warmed up.

Sometimes, on really cold nights, I keep my hands in my pockets, too!

Nick Theodorakis wrote:
During cold weather observing, is it better to keep your eyepieces warm
(e.g., by keeping them in your pocket) so the heat from your face
doesn't fog them, or let them equilibrate to the air temperature as the
rest of the scope does?

Kendrick eyepiece heaters
http://www.kendrick-ai.com/astro/dewremoverphotos.html

- Canopus56