Re: ATM NEW 30 INCH FROM 1 INCH PLATE GLASS !

[Robert Duvall <rduvall@jlc.net>]

At 10:37 AM +0100 12/16/98, alderlie wrote:
>If there are 1300 members on the ATM forum, and only two responds
>to the announcement of a mirror made of a
>30 INCH, 1 INCH THICK PLATE GLASS+ACEAIQ-
>
>Is this not where we where waiting for ?
>Everybody else think this is normal ?
>I would expected some more enthusiasm, for the ATM list.

OK, I thought the list would be inundated, so I didn't post, like so many
others. Also, it's that busy time of year- shopping;)

First, to the guys who did this (and as a FIRST mirror), congrats from
probably all of us. It is indeed a very impressive undertaking. I loved the
long arm curve generator idea, glad it worked for you so well. I was
thinking of doing the same if & when I move up to that size glass. The
progress report on the web site is very instructive also. Sounded to me
like they JUST finished it and that much analysis of performance etc still
need to be made by the builders.

I did have a lot of questions after visiting the site, so let me post a few
to the group, so as to not inundate the good folks who made this telescope
with hundreds of similar questions. I have sent this message on to the
builders seperately.

1) what figure did foucault testing show you obtained, before you called it
'good enough'?
2) any photos of the tests (curiousity has me ask, not disbelief of any
numbers you may report).
3) Any tests on mirror cell performance- "The mirror was then supported on
a sheet of bubble pack and foam carpet." It sounds like very uniform, my
question relates to how it performs at different elevation angles, and have
any star tests been done to test it yet? I would love to see some photos
when possible. Has it been a problem with collimation?
4) was the glass annealed? Any issues of strain seem apparent?





Robert Duvall
Force5 Telescope Making Resources

Software Engineer, Amateur Astronomer (TN),
and General Scientist (according to my son)
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