How long does it take to cool a
large mirror being produced for one of the world’s largest astronomical
telescopes?
Specific Question:
What I want to know is – how
long did it take the mirror to cool off? That's the most amazing part, to me. I
just can't get my head around how you let something like that cool properly, so
it doesn't warp. It's one of those science-y things that gives me shivers.
Answer:
From: Phil M. Breidenbach
Date:
Subject: RE: Subaru Mirror
I can't tell you actual times, but I do know it was close to a year, if
not longer for the glass to cool down. They made a furnace at
this job; in fact, I believe they had to build an entire building to make
the blank. As the glass cooled, it was monitored closely. After the
process of cooling was finished, it was shipped to
grinding and polishing process started. This removed any excessive
warpage
that might have happened during the cool-down process. I believe during the
final polishing processes, they had the blank on the active support
structure to mimic the final resting place of the mirror. This also helped
to avoid any flexing or distortion.
I hope this helped a bit. I envy anyone that has the
opportunity to use
the telescope in any way!
Have a good day!
Phil Breidenbach
AB3AW
member: Amateur Astronomers Association of Pittsburgh
North Hills Amateur Radio Club
Breezeshooters
Active: reader, bibliophile and bicycle rider
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Editor’s Note: This Science question was answered by a very experienced amateur astronomer, named
Phil M. Breidenbach, who also is involved in amateur radio (call sign: AB3AW). Mr. Breidenbach is
employed with the Brashear Division of L-3 Communications. The Brashear Division, located in