Re: ATM Pic du Midi

[epabcc@epa.ericsson.se (Bratislav Curcic)]

> I have heard of the Pic du Midi refractor being stopped down
> for greater acuity. I think you picked the wrong example. 

I think YOU picked the wrong example. Pic du Midi refractor was :

1 not perfect (being non APO it would need to be f/200 or so to get 
  secondary chromatism within 1/4 wave)
2 replaced more than 30 years ago by larger Cassegrain (because of 1)

In short, there is no large refractor on Pic du, stopped down or not.

My qualification of keeping GOOD optics unobstructed still stays. Of 
course that monsters like Yerkes would benefit from stopping down. But 
that's because they're crappy to start with.

(and don't come back with stories how wonderful large refractors are;
I've looked thru 26" Zeiss, and it was CRAPPY)

Bratislav