Off-Axis (Zero Obstruction) Reflector Telescopes

"Leonard" wrote in message
om...
Good point. I don't think they compensate for rough surfaces from high
speed
polishing (mass produced optics). I believe that quality optics are
polished to
a much higher level of surface accuracy and smoothness. Again, IMO, you
get
what you pay for. How about a D&G long focus achromat with a
chromacorr? I bet
they are smooth.

Chromacorrs are not typically optimized for achromats too far over
f/10 or so. It's possible VD would consider some custom correctors-- I
have no idea. I doubt anyone bets against the smoothness comment...

Dan C.

Hello Dan ,Group ,

I have felt for some years now that if V.D.
and D&G Optical Co. would get together and D&G produce a 6 inch F 10
achro. and V.D. make a chromacorr for that F ratio F 10 ,then you
would end up with a superb optical instrument . To the best of my
knowledge D&G does not make an F 8 achro. and the chromacorr is
optimized for F8 . a shame .
Leonard

I thought I'd heard somewhere that AP and Valery were working together to
make a scope with his chromacorr built in.

Mike.

Leonard wrote:
Hello Dan ,Group ,

I have felt for some years now that if V.D.
and D&G Optical Co. would get together and D&G produce a 6 inch F 10
achro. and V.D. make a chromacorr for that F ratio F 10 ,then you
would end up with a superb optical instrument . To the best of my
knowledge D&G does not make an F 8 achro. and the chromacorr is
optimized for F8 . a shame .
Leonard
I have heard of people using the chromacor on scopes a long as f/12.
It's a matter of getting the chromacor the correct distance from the
focal plane. You minimise CA and SA. I've also read about the Meade 6"
and 7" ED refractors with a matched chromacor.

Eric.

I have heard of people using the chromacor on scopes a long as f/12.
It's a matter of getting the chromacor the correct distance from the
focal plane. You minimise CA and SA. I've also read about the Meade 6"
and 7" ED refractors with a matched chromacor.

Eric.

Hi Eric ,

Yes your correct , it can work well with other F
no.s , all I am trying to say is if V.D. made one optimized for the
lowest F ratio scope D&G makes it should be excellent . Just a thought
..
Leonard