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

["Alan Scott" <alanne1956@hotmail.com>]

Nice scope.  By the way, with an eyepiece height of about 10', you may need 
a ladder that won't fit into the trunk of that car!

alan

p.s. - Seriously - is it possible to make a telescope mirror that is 25", 
f4.8, that would weigh under 60 lbs, and would hold any type of a good 
figure?  Never having made one...

>From: "Peter" <peter@kitgear.com>
>To: <atm@mail.johnspics.com>,<atm@atmlist.net>
>Subject: RE: [ATM] Perfect Telescope - was FAILURE, Warning...
>Date: Tue, 31 May 2005 17:37:30 -0400
>
>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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