Optics
Greetings John,
With no external markings tracking origin will be difficult. As an astronomical primary you will want to divorce the cast Aluminium mount and go to a minimum nine point support from the rear surface. Otherwise your cooldown time will be painfully slow. Also, you may find markings on the rear surface of the mirror.
Check back tomorrow and I'll have the name and ISBN of a book for you on Dob construction.
Cheers and a pint
The Dobsonian Telescope
A practicle manual for building large aperture telescopes
Pub. Willmann-Bell
ISBN 0-943396-55-7
If you run across another let me know please
Last edited by etesting2000; 2nd Aug 2009 at 15:11.