Re: [ATM] Secondary Cage Calculations (formula from Kriege +Berry's book)

["Robert Houdart" <robert.houdart@cruxis.be>]

Jacob,

> Does that mean only certain eyepieces are useable with the scope? How
> does the calculation affect illuminated area?

There would be some vignetting from the upper ring, but hardly worth
mentioning for visual observations.

> Am I to understand that if I want a broader f.o.v. for say, a ccd, I
> should shrink the diameter to produce a larger cone? I assume this is
> the case for astrographs.

If you want a larger fully illuminated FOV you should increase the ring
ID. 

In essence the impact of choosing a slightly smaller or larger ring will
be fairly insignificant, both for the optical performance and for the
cost of the telescope.

HTH,
Robert

_______________________________________________
ATM mailing list http://www.atmlist.net/