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(meteorobs) To dew or not to dew...
George et al,
(and others who may have the same problem!)
You wrote:
>skies were clear and calm...but very wet. I had to use the hair dryer each
>time I advanced the film of my cameras.
I think I remember you commenting once that your rotating shutter does help
keep dew down to some degree.
Up north here, in spite of being inland, we tend to get heavy dew in summer
and heavy frost in winter. For our telescopes and cameras, we need
something to not just take dew or frost off, but prevent it from forming.
Yes, the moisture is that bad up here.
We do one of several things. If we are not 'electrically challenged' ;> we
wire a batch of resistors together, or some nichrome wire, and put it around
everything... telescope objective, Telrad or finder scope, and eyepiece...
and get ourselves hooked up with a power source, either big gel cell, or car
lighter socket, or converter to real power.
As for myself, I fall into the 'challenged' category! ;> I did get a friend
to solder some resistors together for me for my scope, and the system is
still working well. However, I wanted both a backup system and more heater
units - for camera work. So, I got myself set up with a 'Kendrick' system.
Jim Kendrick, a member of one of the local clubs I belong to, puts out a
great dew heater system! It's carried by most astro supply places, and is
also available from Jim directly. His ads are in Sky & Tel, and his website
is at http://kendrick-studio.com.
It has a controller, a box with 4 plug-ins for individual heater straps, and
will run either from a gel cel, or car socket (my favorite), or with a power
converter, from regular power. Each heater strap has a long cord, with the
heater part being encased in a narrow 'cuff' that attaches with velcro onto
whatever you want it for. The velcro attachable units come in different
lengths - for different aperature scopes, and different aperature eyepieces.
They work well on cameras too... you just have to be careful not to move the
focus off infinity on your camera. The really nice thing about the Kendrick
system is that the heat is adjustable, so that you can leave it on just a
bit, or put it up all the way to high for severe moisture conditions. It
uses very little power. Although the prices may seem a bit high, these
units are really worth it! They work very well, and none of us up north
here would 'do' without them! ;>
Anyway, just a suggestion, for those who might be interested, and who might
not be familiar with this method of combatting moisture on equipment!
Clear (and dry) skies!
- Cathy
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Cathy Hall, chall@cyberusdot ca
Ottawa, Ontario, Canada
RASC, Royal Astronomical Society of Canada, Kingston Centre
NAMN, North American Meteor Network
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