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>
>
> Now Sam also says "some baffle surfaces should be left glossy" which
> to me implies that he means some baffles other than (or in addition
> to) the side of the tube. This is a very interesting idea which I
> have not seen published. Do you have any references for this or is it
> new? Do any manufacturers do this? It does not seem immediately obvious
> what type of geometry would be best for these directed reflection
> baffles.
>
Hmmm... references... Well, I'm fairly certain I must have read it
somewhere. I can't find it Smith's "Modern Optical Engineering"
I don't *think* I invented it. I'll have to poke through my notes. But
I have used this technique successfully in infrared thermometers. I don't
know if any optical telescope makers use this idea or not, it can be
something of a pain on the manufacturing floor.
Now I find myself in a quandary. I can't describe to you the exact way I've used specular baffles because that info is proprietary. I'm not sure that it would do you much good anyway, since the devices in question would make lousy astronomical telescopes. (In fact, the reason I'm here is to broaden my horizons, I know little beyond textbook basics about telescopes you actually look through. (; ) Try this. Lay out a refractor on paper. Put it in an oversize tube so you have plenty of room to put baffles along the walls. Draw them in. Now trace a few rays with a ruler. If the baffles are specular, any rays that hit a baffle will be directed *out* toward the tube, rather than back into the optical path. Painting the lily a bit, a little more tracing will show you that the *wall* is better left matte in this case.
Sam Paris