In a message dated 5/21/01 3:04:04 PM Eastern Daylight Time,

<< I too have found that having the LX200 out in the open with the roll off
building to be a BIG problem. We often take off the big beautiful Meade dew
shield because it is a wind catcher. Wind will make the image unsteady
forever. This condition is possibly acceptable for viewing but deadly for
imaging. >>

Hi Doc,

Domes are not perfect, for lots of reasons, just better than every other
setup going - particularly if you happen to live in a cold climate! Our RI
winters aren't nearly as cold as yours in WI, but man oh man can that wind
blow - Frosty Drew Observatory is only 1 mile from the Atlantic Ocean. Inside
our 18' AshDome it can get mighty cold, but at least the wind is knocked down
(when not observing in the wind's direction, anyway.) And dew is not a
problem, whereas out on the lawn things can get really soaked. We joke that
we leave that big white dew shield in place all the time only because it
makes the scope look so much bigger to visitors! Trouble is, the Meade
supplied cover for the corrector plate doesn't fit on the dewcap, so we use
the latest in hi-tech gear to cover the open end of scope each night - a
wastebasket liner!

But domes, especially those full of warm bodies and a computer, present a
whole host of thermal problems that you don't have with a roll-off set up.
All of the collected heat can escape only one way - upwards, through the
slit, right in your optical path. Things can really take to shimmering!
Keeping the inside as close in temp. to outdoors is critical, but very
difficult in the cold months. I mean, who wants to leave the doors open when
it's 10 degrees and the wind is howling? When it's been bitterly cold (teens
indoors) we've even had to turn on a small space heater to survive. You can
imagine what that does to your images! But sometimes it's either that or go
into the nearby nature center to thaw out for a half hour, ruining your night
vision in the process!

On calm, dry temperate evenings I'm sure that we would achieve even finer
performance from the 16" if it were out under the stars. No thermal issues to
deal with at all, and no dome to be jogging around all night. But on balance,
a dome will be preferable at least 85% of the time, IMO. No wind, no dew,
fewer bugs, a darker environment around the scope, all the tools close at
hand, etc., etc. But I suppose we could start a pretty good thread just on
that topic.

Let's not. :o)

Doug S
www.frostydrew.org

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