ATM The perfect telescope, sort of

[astillma@nit.AirTouch.COM (Anthony Stillman)]

Refering to Val Germann's basis set for describing Amatis Telescopis.
  
As a self described WORRYWORT-TECHNOCRAT (note this is different from a 
TECHNOCRAT-WORRYWORT as I get somthings done, but am never satisfied and always
wish it was more complicated, so I take it apart and use the pieces in the next
project), I would like some opions on a varity of design options for a large 
project I plan to begin in about 6 months (have to finish the bi-nocs first.)

Specifically, I recently purchased two bird-bath blanks.  One for a song, the
other at Riverside for a Riverside price (thanks Tom.)  The first is 25" in 
diameter and 1.2 inches thick edge to center with a 4.25 inch hole in the 
center and is formed to an f/0.58 curve back and front.  It is strain and 
striation free and appears to be a modern pyrex.  I have not yet tested the 
index or dispersion.  The second in 27" in dia. and is made of old green pyrex. 
It is about 2.5 inches thick at the edge and a bit thicker in the center.  It 
has a rough ground f/0.76 curve and a 5" hole (area) in the center.

I have considered all sorts of designs from a concentric Maksutov with and with 
out a Schmidt correct plate to a "simple" Cassigrain to a modifed Loveday.

Now I know I've made some big assumptions here.  First, for the Mak, that the 
first bird-bath can be be used as a corrector.  I figured here that I couldn't 
design for min color, but could make it concentric and then use a positively
powered Schmidt corrector at the common radius of curvature and compensate for 
both residual spherical aberation and color.  This design has a lot of 
advantages.  It is mostly spherical curves, is almost astigmatism and coma free 
and would have little residual color.  Also, its sealed.  The problem is I 
don't know yet if its even possible with the glass I have, the clear apature 
would be about 22" which seems like a waste and there would be some color.
Yes, I have apature envy, bad.

Now the Cass is neat because it uses the full apature, and there is no color, 
but lets face it, at best I'm going to get maybe f/2.0 out of the big 
bird-bath and probably more like f/1.8  I've parabolized and f/2.25.  
It was hard, really, really hard.  I don't think I can do an f/1.8  Also, the
field curvature of any resonable f/10-f/15 design sucks.

Ok, how about the modified Loveday.  I just thought of this last night, so I
haven't looked at the SC's for the three curves involved, but I have worked 
out that for even a 1" field the f/eff needs to be about f/15.  I'de like more 
field than that and I was hoping for less than f/15. 

Neither the Cass or the Loveday is sealed, which, as Tex said, makes a 
difference.

So, I've TECNOCRATED and WORRYWORTED for months.  HELP!

Can anyone help me consider the options? Suggest alternate designs? Tell me 
to fill them with water and put them in the back yard?  Help me feel like I
not about to hear the theme song from Mission Impossible?

Thanks,

Anthony