[Atmswap] Perkin Elmer flats for sale-

[David Harbour]

To all:

In 1996 I designed and built a rather largish two mirror polar
heliostat/coelostat for our local science and art museum (they have never
installed it or used it). On their behalf I bought two rectangular flat
mirrors for this heliostat that had been manufactured by Perkin Elmer . A
little later, I bought two for myself. I bought these mirrors from Gary
Hand, whom most of you know.

These two flats are very beautiful, cosmetically- new and unused, with
brilliant unmarred coatings. They are approximately seven and a half inches
long, seven inches wide, and seven tenths of an inch thick, and have their
corners cut back at a 45 degree angle. Although there are Blanchard grind
lines around their perimeters, their back sides are fine ground. I have
pictures of the heliostat that I built that show these mirrors (I'd have to
find the CD and off load them into the computer).

They have many potential uses for an amateur telescope maker, probably the
most ideal application would be to fold the optical path of a long focus
refractor with a relatively large objective to shorten the tube length by
about two thirds- the mirrors are large enough to fold the light path of a
ten inch objective (or anything smaller). One of them would also make a very
useful half aperture autocollimator for large mirrors. One might even use
one of them for a very large diagonal. Handy for making a down looking
pedestal binocular holder; or a double pass Foucault tester- probably there
are even more potential uses than I can think of. And, one of them would
serve nicely to test refractor objectives up to seven and a half inches'
aperture with Foucault, which is a null test at focus for a lens.

Mr. Hand sold all 36 of these military surplus flats he had on hand, and
that was all there were, and so no more are available from him. He sure sold
them quickly- I was waiting on a little money so that I could buy several,
but the money was late, and not as much as I'd anticipated, and Gary had
sold all of them except for four. If anyone is interested in these flats,
please correspond with me off list, I check my email several times daily.

David Harbour

scarab2@cox.net