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

["john sherman" <atm@mail.johnspics.com>]

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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