[ATM] Classical Cassegrain or Dall Kirkham ?????????

["Vimal Mamania" <vimal.atm@gmail.com>]

Hi all,

First to introduce my self, I'm Vimal. M. From Mumbai (India) and I'm interested in ATM very much. Currently I'm working on 6" f/8 and 15" f/5.

One of my friend and I'm also planning to build a catadioptric, preferably around 12" or 14" diameter. Anybody with previous experience on the same, pls. tell us which design to go for out of the three?
 
1)      Ritchey Chrétien
2)      Dall Kirkham
3)      Classical Cassegrain
 
We understand it is difficult to figure the secondary. The easiest & safest type would be a Dall Kirkham but the focal ration has to be around F/15 + .  we would rather prefer to make a Classical around F/12 .
 
pls. note that we don't get Pyrex easily in India (specifically in larger size and smaller disks also are too expensive). and plate glass is available with max 3/4" to 1" thickness.

Can anybody suggest the best solution ? and pros and cons of each. 

Regards,

Vimal Mamania
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