[ATM] Orientation of Objective

["Bob Walker" <tac@i1.net>]

I'm building a refractor, and I'm not sure which way to orient the
objective.  It's an 8.5" f/12.5 airspaced doublet. I don't know what type it
is since I bought it, already in a cell. Both surfaces are convex, though
one has something like twice the sagitta of the other.  The cell is
constructed so the lens rests against  a full annular lip on one side, while
three small clips retain it on the other.  From an engineering standpoint,
it would seem the clips should be skyward so the lens will be supported all
the way around its edge when elevated.  This would put the more strongly
curved surface skyward.  Does that sound right to you refractor experts, or
is this even enough information to tell?  I'd appreciate an off-list reply
since I get the Digest, and I'd like to get the lens mounted tonight if
possible.

 *  Best regards, Bob
*
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