Re: [ATM] Flat grinding the back of the primary mirror

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

Grinding the back and sides is only done to gain a regular
surface.  Theoreteciall, they should be polished.  However
realith sets in and polishing such surfaces really doesn't do
anything to improving the action of the mirror.  If you plan in
selling the resultant mirrors, you will be wanting to make a lot
more than two of them and ground surfaces do tend to indicate
"attention to detail" that otherwise would be missing.  Then
again, if you 're making a lot of mirrors, you will have the
machines to grind surfaces flat real fast.

If you're just making the scopes for yourself, I'd check for your
eye height and build a scope that would allow you to stand
straight up when the scope is at about 75deg. or so, depending
upon where you are on the earth (really just set the scope for
about the highest that a planet can get) and build your planetary
scope to that length.  The longeer the focal length of the scope,
the better the magnification of the planets would be.
Bob May
bobmay at nethere.com
http: slash /nav.to slash bobmay
http: slash /bobmay dot astronomy.net
Replace the obvious words with the proper character.

_______________________________________________
ATM mailing list http://www.atmlist.net/