Re: [ATM] Time for a "new standard" ATM telescope project?

["Eric S. Johansson" <esj@harvee.org>]

David Weinshenker wrote:
> With increased secondary ratio, a smaller secondary is needed 
> (less obstruction) and the ideal "hyperbolic" surface approaches 
> a pure sphere (easier to figure) - for example, T.R. Endemann 
> (S+T, Nov 1998, p.121-126) describes an 8-in. f/70 "Planetary 
> Astrographic Telescope" with an f/4 primary, and notes that it 
> works quite well with a spherical secondary mirror (which he 
> calculates to be within 1/10 wave of the "optimum" hyperbolic 
> curve for the 17.5:1 secondary ratio).

someone mentioned that to me last night at the ATMoB clubhouse.  Thanks for the 
reference so I can go look in my archives.  Unfortunately, I have to solve 
another problem first which is "how do you make a mirror if your hands don't 
work?"  RSI has removed the lot of activities from my life.  I've been able to 
compensate some by using speech recognition, but I've yet to see speech move a 
mirror although I have seen a mirror move someone to speak, or more accurately, 
swear.  :-)

In a nutshell, I would need to build a machine/technique that would allow me to 
do absolutely everything by machine, grinding, fine grinding, polishing, and 
figuring.  I suspect it would be easier to create spherical surfaces.  :-)  then 
I could turn the mirror over to someone with working hands for figuring to 
non-spherical configurations.

in any case, if I could figure out how to build such a mirror grinding machine, 
I have a bunch of six-inch blanks that have been partially ground I could use 
for experimentation.

> Another alternative: mount a CCD camera at the prime focus, 
> and view electronically from ground level: there's some awfully 
> compact industrial Firewire cameras out there... I've got a 
> brochure on the AVT "Guppy" models, which are 48mm long and 
> 30x30mm square in cross section: the C-mount (1in x 32 TPI) 
> port basically takes up the front of the camera body; the whole 
> camera wouldn't be a very severe central obstruction for a 10 
> inch telescope!

but but but I really like caressing my eyeball with the subtle colors of Jupiter 
and Mars.  The shading and the detail you can see in something like a schupmann 
is truly wonderful.  Truth be told, my ideal telescope is a schupmann but my 
chances of ever owning one let alone finding a place to mount it is vanishingly 
small.  what ever scope I end up using for planets, I would love to have one of 
those color correction devices that function like the schupmann's color 
correction controls.  You don't know how sweet those controls are until you 
spent an evening working with them and learning how they affect your ability to 
see detail and color on a planet.  Oh baby I am so spoiled.  FYI, the trade-off 
the universe has given me for not being able to see gray fuzzies seems to be 
enhanced color vision.  I see colors others don't (usually in the red although 
blue shows up in a lot of black dyes in clothing) and I can see shades with 
finer resolution than most people do.

I'll do web cam photography because you can get some nice pictures but, unless 
you're part of observing program, they're not terribly useful except to show off 
how many hours you spent in front of the computer instead of the telescope.

-- 
Speech-recognition in use.  It makes mistakes, I correct some.
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