Re: [ATM] Flat Field Cass with Hougthon subaperture corrector. WAS:corrected dall-kirkham telescope

[Dominic-Luc Webb <dlwebb@canit.se>]

On Thu, 8 Feb 2007, Gregg Swanson wrote:

> The company is working on a design for 12.5" scope...
>
> Would it be possible for an ATM to build the optics for this sort of scope? Would it be possible to purchase the correcting lenses off the shelf?
>
> Gregg

I have not seriously looked into this particular design, yet, but
I certainly will at this point. All the systems I am working on
right now are catadioptric and are generally 12.5" plate glass
primaries. Because I'm experimenting, I use low-iron plate glass
for Schmidts, which is essentially colorless in the visible spectrum.
I have 11" BK7 Mak corrector. I have a couple prescriptions for this,
but so far nothing approaching the theoretical spot diagrams shown
on that website. I have seen one or two others that looked better
than the original designs I had planned and I halted work. This was
partly because I seriously believed I was wasting a valuable
corrector blank on a design I need to improve, somehow.

Since I already have the glass (primaries already ground and mostly
polished F/1.0 to F/3.5), I am tempted to go ahead and try to make
one myself. This might be more interesting undertaking that just
one more Schmidt.

Dominic-Luc Webb

_______________________________________________
ATM mailing list http://www.atmlist.net/