[ATM] Small flexed telescope

[Christian Maciel <jeeperbr@yahoo.com.br>]

I think I will restart a line of talk here ;-)

I was “cleaning up” what my wife calls “disaster room” (my projects shop) when I found out some optics long forgotten.

1- 4.5” F2.8 spherical mirror. (1/16 lambda if I recall), ¾” of what seems to be Pyrex, the back is unpolished, but seems quite well ground.
2- 5” optical window with center hole. (good, not great, taken from a SCT)
3- A few assorted flat diagonals (from 2” down to ¾”)
4- 2” cassegrain secondary (bought on e-bay from adastra )

My original idea when I got items 1 and 4 was to make a coude cassegrain (or imperforated cassegrain) refiguring the primary mirror.

That project got buried under the lack of time ………………….

Right now I am looking at this material and dreaming on a quite fast newtonian without vanes.

Construction would follow the normal design of a vaneless Newtonian, using the optical window to support the diagonal mirror.

The big difference would be that I would do a flex primary cell and try to flex it.

I ran flex.exe and wasn’t able to find a failure in the project, the wedge has to be small, but even then it seems to be within spec. 

Questions :

1- Has someone tried something similar?
2- Can someone see any mistakes?
3- In order to reduce coma the best thing would be to use a hyperboloid primary with field flattener lenses associated, does anyone knows the formulas to calculate a puller to get a hyperbolic secondary?


Before anyone says, I know aperture is small, that it will be a limited project, but in my opinion it still seems interesting in order to see if it can be accomplished.

Clear skies
Christian Maciel


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