From: "John Murray" 
To: "Amateur Telescope Makers" 
Reply-To: "John Murray" 


G'day Everyone,
        A member of our group (Mick) has had the good luck to be given
an aluminised mirror from the widow of the person who made it. The chap who
made it was an active mirror maker many years ago and his widow would like
to see the mirror put into a scope. After testing it, I found the following
details

Diameter        230mm
ROC             4200mm!!

        This makes it approximately  a nine inch F-10 mirror!! After
allowing the mirror to acclimatise (24 hrs)before testing  we can see that
the surface is very smooth with very gentle ronchi lines. Getting readings
with the ronchi and foucault proved extremely difficult. The shadows moved
at the slight thought! of movement. Any suggestions for this?
        Mick and a mate who is a boilermaker are considering making an
Alt/Az based on ideas from Berrys book "How to make a Telescope".
Being a boilermaker though they are both looking at making the entire mount
from tubing and welding it. Any ideas on whether this would work or suffer
any effects due to being made from metal? I've thought of vibration and
weight so far but any thing else? They believe they can make it quite
light.

Cheers

John Murray
Whyalla
South Australia

--- BBBS/NT v4.00 MP