Re: ATM cass vs. greg

[Anthony Stillman <atmer@flash.net>]

One of these days I'm going to stop making mistakes, but then I'll be dead.
Until then, I'll just keep correcting them.

Onece again I've switched plus for minus.  My previous mea culpa should read:


The conic constant of the secondary of a classical cassigrain or gregorian is:

   - ((m+1)/(m-1))^2

where m is the magnification factor, NEGATIVE for a cassigrain, POSITIVE
for a gregorian.

And:
I still know of no easy axial NULL test for an oblate spheroid.


Anthony