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Re: [ATM] Advice on Solar scopes/observation
tony gondola wrote:
> That's ok for quick and dirty, low power viewing. It is a very safe solution
> which is a big concern for "sidewalk" situations. The problem is you're
> using a very low quality optical window. If you try to push the quality of
> the image with something like this the need for an optical quality window
> becomes paramount. That suddenly makes the project much more difficult and
> expensive.
An important point about any attempt to do higher power solar observing
is the big problem with heat. Both the telescope and the surroundings
will have big heating trouble. If you think tube currents and
atmospheric heating are a problem at night, the day will be much worse.
I don't know the tried and true solutions to these problems, but I do
know that if you want to do much more than low power observing, you will
have to address this situation.
Some pretty obvious things are observe over a large field of grass or a
lake, not over pavement, bare ground or buildings. Paint telescope
bright white. (There is a special white paint used just for this
purpose. It has been mentioned on this list, so try searching the
archives.) If you can't find the special paint, then use a bright
white, non glossy paint. Put a shade over the upper end of the scope
that acts as an umbrella to put as much of the scope as possible in the
shade. Consider strongly active tube ventilation. Consider insulating
the tube wall with cork or similar. Consider some sort of double wall
tube with positive air flow through the gap.
Somebody is selling a Herschel wedge. It was mentioned in S&T some time
back. A Herschel wedge might be the easiest way to get full aperture
performance. On the other hand, a good quality full aperture filter
rejects most of the energy before it gets into the optic tube, thus
helping the thermal management problem.
--
Mark Holm
mdholm@telerama.com
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