Re: ATM Not hard

[Anthony Stillman <atmer@flash.net>]

Years ago most amateurs were limited to six or eight inch apatures by cost
and the avalibility of pyrex.  Only professionals would tackle the
tremendious dificulty and great expence of making a telescope as large as
12 inches.  As the activity became more popular and pyrex less expensive, a
few brave amateurs built 12" and even 16" telescopes.  Of course they used
blanks with the traditional 6:1 diameter to thickness ratio, because they
KNEW that to use thiner glass would result in instruments which were
useless.  About two decades ago a revel named Dobson and his entourage
started making large telescopes, 14", 16" even 24" out of thin plate and
pyrex glass.  They were looked on with disdain and derision by the general
ATM community, because we KNEW better(1).  Now of course this is rather
common and even professional astronomers who have been known to be, how
shall I say it, OK I'll be nice, stuck up ba-----ds(2), are asking amateurs
for access to these instruments(3.)  Note, please don't confuse
pro-astronomers with pro-telescope makers, who, as a rule, are nice people.
In any case, I digress.  The 6:1 ratio limits the size of the apature by
sear weight.  I have trouble hauling a full thickness 12" blank and tool
around and I'm a big guy.  Frankly, that's the largest mirror I can polish
by hand.  Together, two people can and have managed to polish up to 36"
blanks using sub-diameter tools. The only real issue there was keeping them
hydrated.  Also, as the mirror gets larger and heavier the mount must
become more substantial and more time, thought and effort must go into its
design and fabracation.  Think about it, an amateur telescope may weight up
to a thousand pounds or more and yet can be pointed with arc second
accurcy.  Of course we ATMs have never been stopped by the chalange, slowed
down a bit, but not stopped.  I believe, this is why so many innovation in
telescope making have been pioneered by amateurs.  This and the fact that
pro-TMs have to struggle just to make ends meet and can't afford to take
that many risks.  Of course it helps that we don't know any better.

How big a telescope can an amateur make?  Now, I think the skys the limit,
and maybe not even that.  But if you do make a large research grade
instrument, don't be suprised when pro-astronomers tell you only they can
make GOOD use of it and then charge you for the privledge of listening to
them(4).

Anthony



1) Yes, I onece was one such person.  I apologies.

2) If I have offended any professional astronomers, good!  Now get your ass
out to a star party and help out.  Also, try to be humble in the face of
popular ignorance among the those of us who don't have twevel years of
ivory tower education.  We pay the taxes that build the telescopes and pay
your saleries which allow you to persue pure knowledge for its own sake and
damn it, you owe us.

3) To be fair, I know a few professional astronomers who are quite nice
people, but there names shall remain secret least they be shunned by their
peers.

4) That's directed at you S&T and your pay "Amateur pro symposium".