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[Chicago Astronomer - Astro Joe]

Solar testing a 4.5" Meade Reflector Scope

23 May 2012

While prepping for tonight's Chicago Astronomer star party, I came across this 4.5" Meade Reflector scope. Donated to the Chicago Astronomer by a fan last year, I wondered if it could be put into service for our sessions.

The primary mirror was dirty and after cleaning it, It looked like someone before me tried to clean it...as it displays scratches in all directions. The mount was incredible wobbly and after taking it apart and reassembling the pieces snugly, it performed better than ever, albeit the damping time on vibrations was poor.

And to top it off...it's a .096 focuser.

.096 eyepieces are quite limited on what they can do....but could this Meade be suitable for some solar work?

Let's find out.

Using the same portable screen that I used for the 2004 Venus Transit..and with the same sheet of white paper - I projected the solar disk into the sheet as it was propped up on top of a garbage can, popped in a 25mm .096 junk eyepiece...and was pleasantly surprised...

I got some decent sunspot displays, but nothing incredibly sharp or detailed. Curious on the light and heat bouncing around inside the tube, I felt around the innards and things were quite warm, but not hot. Nothing melted nor smoked for the 1/2 hour I tested the scope.

Righteous...

I also tried out the De-lite screens...and really...I prefer the plain white paper sheet to the projection screens. Except, the "Dual View" sheet was good at rear projection of the disk.

This could be put into service for the Venusian Transit - pending on a Astronomer to man it.

[tomlee]

so you are not using a Solar filter here, right Joe?

[Chicago Astronomer - Astro Joe]

You are correct.

No solar filtering involved here.

Just direct raw solar rays, bouncing around in the tube and projected onto the screen. And really, no harm to the equipment in this short test.

[Paulie pchris00]

Maybe this is a stupid question, but what about a really hot, stifling day? With a breeze and a mild day to help dissipate heat, it might not be a problem. But what about 90 degrees? Would heat build up in the tube if it had no way to escape?

[tomlee]

I have no filter so I probably use my refractor and ground glass for vented rear projection 3.5x4.375 in.