RE: [ATM] Perfect Telescope - was FAILURE, Warning...

["Peter" <peter@kitgear.com>]

How does this sound for my perfect scope:

- 25" f/4.8
- total weight 75lbs
- setup in 10 minutes, tear down in 5
- heaviest part is 60lbs which includes the mirror box, rocker, mirror and
base
- eyepiece height is 67"
- packed height of the mirror box and rocker is only 12.5" high to fit
easily into the trunk of almost any car
- trusses which come apart like pool cues so none are longer than 40". Fits
in the trunk of almost any car.
- all aluminum and composite parts to be weather resistant and last almost
forever

Peter

-----Original Message-----
From: atm-bounces@atmlist.net [mailto:atm-bounces@atmlist.net]On Behalf
Of john sherman
Sent: Tuesday, May 31, 2005 5:45 PM
To: atm@atmlist.net
Subject: RE: [ATM] Perfect Telescope - was FAILURE, Warning...



Hi Alan,

>* I can lift it.  Each seperable part must be under 45 pounds.

Steven Overholt used to lug a 30" scope in the back of a tiny hatchback. He
lifted each piece, but the mirror box was a tad over your limit.

Anyway, I think the perfect scope is one that's over 20" aperture - big
enough to show you what it's pointing at. I also wish it was under 45 lbs.

>  >* Somewhere around an f5.
>  Much faster and the images aren't as sharp.

See, here's where I run into a problem. A parabola always produces a perfect
image on-axis*. Even at f/1 - that's what makes it a parabola. If you know
someone who can make a parabola, instead of an insufficient facsimile, you
can go lots faster than f/5. When the on-axis light is properly focused, the
coma is not much of an annoyance, even faster than f/4. Just be sure all
your refractive elements can handle the cone.

I understand a certain 28" f/3.7 made quite a stir down in
Florida, recently....

John


* A refractor never does.








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