Re: ATM 26" BVC blank

["Ron Dyvig" <rondyv@gwtc.net>]

Paulo,

     F/3.6 is something you can probably handle o.k., but be aware that the
RC may continue to get shorter as you complete rough and fine grinding.
That happened to my when I did my 26".  I had f/5.0 at the end of rough
grinding, and it had shortened to f/4.8 by the time I was ready to polish.
I worked with the mirror on the bottom throughout.  In your case, you may
not want to get any shorter than you are now to avoid overshooting the
design range of the Paracorr.

Good luck,

Ron Dyvig
Badlands Observatory
Quinn, SD


----- Original Message -----
From: <Astropaulo@aol.com>
To: <atm@shore.net>
Sent: Thursday, April 06, 2000 7:22 PM
Subject: ATM 26" BVC blank


>
> Hi All,
>
> I've been getting my tool matched up with the blank and getting all the
> bigger pits out with 80 grit. I have figured out I'm in F 3.6 country
instead
> of 4.0 so I'm trying to decide if I should just stick with the 3.6. The
scope
> is going to start life as a Newtonian(with a Paracorr to correct the coma)
> and then hopefully become a Nasmyth Cass when I figure out how to make and
> test a convex secondary. Any thoughts on this plan from you folks out
there?
>
> Cheers,
>
> Paulo
>