Re: [Fwd: ] ATMJ article on grinding a 6" by Russell and Germann

["Andy Steere" <andy@www.system.missouri.edu>]

On Wed, 12 Feb 1997, Richard Baier <baierr@einstein.franklin.edu> wrote:

> Dr. Mark D. Russell and Val German claim that that by using a precurved
> 6 inch precurved mirror blank, polishing pads and a "modified star test"
> the amateur can make a 5.75" mirror with apochromat like quality.

I have not been directly involved with their research since the "Mirror in
a Day" project at Astrofest last fall... and I haven't seen the article in
question yet.  So, I won't be able to help out much until I speak directly
with them both this weekend.  

I do know the latest Astrofest project created a mirror that was better
than expected.  It would be most unlike them to leave that little fact
"well enough alone".

> They also make mention of displaying to the public at Riverside '95 and
> Astrofest '95 two eight inch reflectors to see if the general public
> could distinguish differing levels of optical quality.  Did anyone see
> these instruments and how did they perform?  What were their focal ratios?

This I can help with... as I helped administer the survey that was done in
both California at RTMC and in Illinois at Astrofest.  The scopes in
question were 8" f/6 and NOT designed to be really good.  The test wasn't
of the optics at all... but rather the participant's perceptions and
opinions of what they saw.  A baseline, if you will.  That research isn't
completed yet. They are still interested in finding the limits....  to
answer the nagging question of "just how good should it be?".

Some more information (and pictures!), of the projects I've mentioned, is
available in the Star Party section of the web site listed below.

Clear skies!

Andy Steere - andy@www.system.missouri.edu
President - Central Missouri Astronomical Association
http://www.system.missouri.edu/andy/