Re: Observation/Cold Weather Gear Test Report
- From: deathcow@xxxxxxxxx
- Date: 29 Dec 2005 00:51:20 -0800
I've lived near Anchorage, Alaska for the last 28 years. My cutoff for
observing is -5F (-20C). Every couple degrees between -5F (-20C) and
10F (-12C) help a LOT. Those 15 degrees are much more important than
any other 15 degrees!! I can observe all night at 10F (-12C), but
down at -5F I'm good for an hour or two.
No matter the temperature, I don't ever wear more than just blue jeans
for my legs. I wear normal socks and Timberland boots and that seems to
handle the feet just fine. I'll wear a flannel long sleeve shirt and a
good large down jacket. A good warm hat is the most important item of
all, I like the kind that wrap down around the ears and fasten under
the chin (we call them dog musher hats). Gloves are good to have around
but super annoying, I have to take them off all the time for focusing
and changing EP's and they usually end up off. Hats are essential !!
Thermal care of the scope, binoviewers, eyepieces and other
accessories, to me, is paramount. Humidity control around optics is
absolutely essential. For big temperature changes (sometimes 75F change
here), repeat after me:
* I will _always_ bring a scope out in a sealed case, and allow it to
come to temperature in the case.
* I will _always_ leave the lens capped for 15 or 20 minutes after
bringing the scope out of the case.
* I will always keep the scope case closed as much as possible when its
outside.
* I will always put a PWT dessicant scope plug in the focuser before
putting it back in the case. (Extra dessicant packs throughout the
case certainly do not hurt.)
* I will always let the scope warm back up for at least 12 hours before
opening the case again.
* I will always put my binoviewers, eyepieces, cameras, etc. in sealed
tupperware or ziplock containers before bringing them back in the warm
house.
This works perfectly for me with extreme temp. changes. I can swing my
scope by 75 degrees twice daily and there is no condensation anywhere
on the scope or lens ever. (Except for frost on the outside of the
tube... sometimes lots of frost, mostly from breath I think.)
Use a dew heater if your environment needs one, mine does not. It's
almost always bone dry outside in the Winter here. I do use a long
insulated dew shield add on to keep the offhand frost crystal from
forming on the lens.
When it gets down to 0F, keeping the human happy is easy. Keeping the
mount and scope working is not too bad. Keeping eyepieces happy is
practically IMPOSSIBLE !! (Pulls out last hair before it can turn
gray!) At 0F to -5F, for me: Tupperware or Ziplocs, Lens Pens and a
warm house nearby become essential observing tools. Eyepieces wont last
too long before a hot and humid human fogs them up. Then I put them in
the case, seal it, and bring it indoors for 20 minutes to warm up.
Bring them out, Lens Pen them if they need it, and repeat the process
until they fog again. There is absolutely no way on this Earth I can
think of to prevent eyepieces at an ambient temperature of 0F to keep
from fogging with a breathing human mouth constantly inches away. I
breath out the side of my mouth, otherwise they would fog immediately.
I have not tried eyepiece heaters but I really stay away from anything
that disturbs nicely cooled down systems. I doubt a eyepiece warmed to
10F would fair any better?
.
- References:
- Observation/Cold Weather Gear Test Report
- From: John Nichols
- Observation/Cold Weather Gear Test Report
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