Re: ATM Newbie question on 8" f8

["Bill T." <twentiethwave@hotmail.com>]

Hi Brian,

An 8" is easy.  One of my favorite scopes is an 8", f8.  From a comfortable
standing position one can fly through  the high elevations (where seeing is
usually best) with great ease.  Even when tilted down the eyepiece is still
at a comforable height thanks to the high elevation bearings.  The tube fits
nicely into a compact sedan with the passenger seat tilted all the way back.
The base rides on the left back seat.  Here are some pics:

http://www.kupercontrols.com/dob8.htm

Small f8 and f6 mirrors are very easy to figure*.  I figured the 8" f8 with
just a few minutes of long, over the center strokes with tool on top, and
just a little sideways motion.  An f6 might need a few additional tweaks to
the center, a few wide strokes with mirror on top.  The real problem at
those long ratios is not over doing it.

BVC is somewhat softer and easier to scratch than glass.  You should also
consider just plain old plate glass, which is coming back into favor.  With
such a shallow curve, you could get away with a thin and cheap piece.  The
only problem with plate is that you may have to let the mirror cool down
little longer (than Pyrex or BVC) between figuring sessions and evaluation
sessions.

Don't be shy about going to a bigger aperture.  A 10" is still very
realistic for a first mirror.

Bill Tondreau

*once you've beat your brains figuring one for the first time!