Re: ATM 3" 75mm or 4" 100mm eyepieces

[Mark Suchting <masuch@dap.CSIRO.AU>]

On Mon, 19 Aug 1996 K1JJ@aol.com wrote:

> Anyone else lend a suggession? I really need to build up an 75mm  3" and
> 100mm 4" eyepiece....I'm stuck with an F8.5 system here.

Tom,

Some quick arithmatic tells me that even for a 7mm pupil ( the maximum 
for young eyes ) a 60mm focal length will be the lowest power if yu don't 
want to throw away your precious light. A Meade or televue 55mm plossl 
will do the job. I sometimes use a 24" f10 cass with one of these 
eyepieces and have no complaints about the field of view, though the 
power is too low for nice contrast in my view. If you want to use a 100 
mm eyepiece, why not build a 12 " scope with a standars eyepiece as this 
will be all the light your eye will get from a 22' at this power.

For good info on eyepiece building try Sam Browns All About Telescopes.

If you combine two objectives from a 7X50 binocular you should get a 
100mm or so Plossl.