[ATM] 22"

[Tom Wicker <tomofreno2000@yahoo.com>]

Dominic-Luc, 
I have no experience at making an f/3 elipsoidal
primary, and thought it may be quite difficult due to
the greater deviation from a sphere at small f#. I
thought maybe doable since with an e of 0.7 or so it
does not need as much correction from a sphere as a
parabola. I have made a 22" f/4.3 for a Newtonian and
it was not easy for me. I found it difficult to get
outer zones correct without spoiling inner zones and
vice versa. I just thought such a scope would be great
for astrophotography with its large flat field, and
the only folded optic design I might have some hope of
making. I think a bigger problem for me is obtaining a
GEM mount/drive large enough to handle such a scope
without paying more than I paid for my car. I don't
like to spend too much on a hobby, so I try to make
everything to keep a low budget - the 22" blank was
free. Thank you for the comments.


 
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