Sky & Telescope - July 2019 - 73

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That meant putting the mirror on
top, just like amateurs have been doing
since Jean Texereau published his seminal book La Construction du Télescope
d'Amateur. And it worked.
Mel was so impressed with David's
results that he ground 10″, 13″ and 25″
meniscus mirrors - the latter two featured in our January 2012 and February
2019 issues, respectively - and he had
David slump a pair of 30″ blanks and a
pair of 42″ blanks for eventual big binoscopes. (Yes, Mel is crazy, too.)
Enter Tom Otvos. All he wanted was
a medium-big, portable scope. Portability meant fast, to cut down on the
overall length, and fast meant a meniscus mirror. So even though he had only
ground one 8″ mirror before, Tom retrofitted a ceramics kiln with a computerized controller, slumped a blank, and set
to work. Because he was enamored of
Mel's "Zipdob" design (S&T: Jan. 2012,
p. 62), he consulted Mel on the grinding and polishing particulars, confessing that "Mel made it look easy. K inda
naïve on my part."
Indeed, fast, thin mirrors are no
picnic, but they're doable with patience
and attention to detail. Despite a tragic
tip-out accident during star-testing that
broke his first attempt into two pieces,
Tom completed a second 14″ f/2.6 mirror in about seven months and turned it
into a fabulous rich-field telescope. He
even silvered his own mirror, which will
be the subject of a future column.
My point in telling you all this is that
the technology has matured. David (and,
to be fair, several others as well) did the
pioneering, Mel (and, again, others) did
the proving out, and Tom is the demonstration that kiln-slumped meniscus
mirrors are ready for prime time.
You want a big, fast, yet lightweight
scope? Start with a kiln.
For more information, contact David
at prepitious@gmail.com, and Tom at
tom.otvos@gmail.com, or visit his website at astronomy.tomotvos.ca, as well
as Mel's website at bbastrodesigns.com.

Insight

TM

■ Contributing Editor JERRY OLTION
believes you don't have to be crazy to
grind an ultrafast mirror, but it helps.

http://InsightCruises.com/events/st10
s k y a n d t e l e s c o p e . c o m * J U LY 2 0 1 9

73


http://www.obsessiontelescopes.com http://astronomy.tomotvos.ca http://www.bbastrodesigns.com http://www.InsightCruises.com/events/st10 http://www.skyandtelescope.com

Sky & Telescope - July 2019

Table of Contents for the Digital Edition of Sky & Telescope - July 2019

Contents
Sky & Telescope - July 2019 - Cover1
Sky & Telescope - July 2019 - Cover2
Sky & Telescope - July 2019 - 1
Sky & Telescope - July 2019 - Contents
Sky & Telescope - July 2019 - 3
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