Image of the day

Captured by
David Marks

Lightning in the desert

My Account

New to Astromart?

Register an account...

Need Help?

Periscope accessory for Newtonians

Started by jacobson, 01/25/2010 12:51PM
Posted 01/25/2010 12:51PM Opening Post
I am building a periscope accessory that will attach to the side of a big Newtonian to lower the eyepiece height. Does anyone know if this has been done before? I've heard of a periscopic Newtonian that was spotted many years ago at the Texas Star Party.
Posted 01/25/2010 06:15PM #1
Sounds very interesting. Are you going to increase the
F-ratio with a Barlow, etc., before relaying the beam?
Posted 01/27/2010 11:03PM | Edited 01/30/2010 05:02PM #2
Hi Dick,

There was a telescope design I heard of that created a collimated beam by using a special curved secondary. The scope I think was called an Afocul Mersenne. There was a fellow in Texas Clyde Bone, that essentially "relayed" the afocal image down to the bottom of his 20" dob, then re-imaged the parallel light with a refractor. His main concern was being able to sit down while viewing.

I recall hearing there was some unusual effects with this design, one of them was a lot of field curvature.

I have tried some simple relay experiments, and found it was possible for a newtonian to give a correct view image !

If Vladimir is still around, he could give you some concrete info on any pitfalls to this idea.


[COLOR="Blue"]
Dick Jacobson said:

I am building a periscope accessory that will attach to the side of a big Newtonian to lower the eyepiece height. Does anyone know if this has been done before? I've heard of a periscopic Newtonian that was spotted many years ago at the Texas Star Party.
[/COLOR]

Attached Image:

David Simons's attachment for post 135354

David Simons