Re: ATM : Additional Secondary for guiding

["B. Pepin" <atmjedit@conceptsnet.com>]

A tiny section of first-surface mirror placed right ON the secondary at a
slight angle was used for this purpose with great success by the recently
deceased Arizona observer and astrophotographer Pierre Schwaar, and was
described in print, possibly in S&T but I don't remember the date. The light
loss proved insignificant.

----- Original Message -----
From: Ulhas Deshpande <ulhas@nagpur.dot.net.in>
To: ATM <atm@shore.net>
Sent: Friday, August 25, 2000 12:32 AM
Subject: ATM : Additional Secondary for guiding ( was offcenter secondary)


>
> Hello all
>  Have following the discussions on placing a second secondary (!) for
> guiding.
> Why not make a hole in the main secondary -ala Cassegrain- and place a
> second flat behind the first ,inline and perhaps on the same diagonal
> support. this should avoid all problems. Surely a small hole would not
cause
> any significant light loss.
> Just a thought
> Ulhas
>
>