Re: ATM 14.5.I.S..........secondary

[Marty.T@t-online.de (Martin Trittelvitz)]

natsp schrieb:
> 
> what size secondary do i need?
> the focal legnth is 72 5/8" now that its
> polished and partily parabolized.
> i would like to make a secondary,
> instead of buying one.
> i was told they are hard to make strait
> but i cant belive its much harder than grinding a parabol.
> i want to make every part of the scope
> from the internet and from scrap stuff.
> at focal legnth the sun is about the size of a quarter.
> ps: im looking for foucaults for dummiees,----instructions..
> ive been reaserching a week
> and still cant grasp it..
> take care
> stan

beleive me: it is harder to make a flat than a parabol! It is as hard as
to make a parabol with an exact focal length, told before beginning.
Exact means exact to 1/1000 mm!
marty
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