Re: ATM 18" First Light

["Bob May" <bobmay@nethere.com>]

You're right in looking at the sky with the mirror still uncoated!  You're
doing the final test on what the quality of the mirror really is.  I ask
each of the people in the mirror making group to get their scope built
before they get the mirror finished figuring so that they can put the mirror
into the scope and use it and verify that the mirror really is as good as it
seems to be on the Foucault test.  Remember that you are getting a 4%
reflection of the light with just bare glass.  That's enough to see the
Double-Double in Lyra and, on a 6" mirror, split the pairs.  Larger mirrors
will do that even better.
Bob May
http://nav.to/bobmay
bobmay@nethere.com
NEW! http://bobmay.astronomy.net