From: "Mel Bartels" 
To: "ATM" 
Reply-To: "Mel Bartels" 


>>>  I am not thinking of thinner material but larger apertures.

The thinnest attempt I ever saw was a 1 inch thick x 48 inch plate glass.
Unfortunately it shattered when a hot pitch lap was placed on it.  A
successful 27 inch mirror was made out of the largest remaining piece, I
believe.

>>> > Dave Sopchak made an 18" mirror
> out of 0.875" glass and another follow on the ATM list made a
nice 20" out
> of 0.875" glass
>>> Do you know, how good this mirrors perform?

Excellently with no trace of 'stig and incredibly fast cool down times,
having observed with his scope at both the Winter Star Party in Florida and
the Oregon Star Party (interesting how his scopes made it from coast to
coast).  His all aluminum scope designs are worth looking at too, not to
mention his software efforts with the MacDOB project.

Mel Bartels

--- BBBS/NT v4.00 MP