Re: ATM Cast Aluminum mirror

[andydtg@alpha1.phoenix.net]

Kreig McBride wrote:

>Aluminum has been used for some relativly large mirrors. I remember one 
>with an aperture of around 50+ inches was described in a Sky & Telescope 
>article back in the 70's. The mirror was supported through the central 
>hole and the thickness was tapered, decreasing towards the edge. The 
>mirror looked similar to that of an SCT mirror blank.

We were doing field testing of some Apollo program optics at Kitt Peak
in the late 60's when I got to look thru a 50" scope with an aluminum
primary mirror. This was a prototype of a remotely operated telescope.
Saturn was the target & as I recall you could just barely tell that
the ring was a separate structure from the planet, the operators said
the mirror was not very good optically & they mostly used it for IR
photometry.

Andy
Andy Saulietis / DTG Alt-Az-Fp Drive Systems
12617 Harriet Ln
Santa Fe, TX 77510 USA
409-925-8854 Voice/Fax