Re: ATM Experience in solar filter for amateurs

["Chris Westland" <westland@uxmail.ust.hk>]

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> From: Rik Hill <rhill@lpl.arizona.edu>
> Years ago Criterion made a solar eyepiece filter for their 
> Newtonian telescopes. It was mounted like a barlow lens
> and the first surface of the filter was ALUMINIZED. This 
> reflected most of the light and heat back out of the telescope.
> It worked quite well and I know of no case where one of those
> cracked during observation.
> *             

I believe these are called Herschel (sp?) wedges ... they were the original
solar filters.  They have not been sold recently because of the possibility
of breakage ... but they were sold widely in the 50s and 60s I believe

-c