Re: ATM Fine Grinding/Polishing an F4.7

["Bob May" <bobmay@nethere.com>]

You probably aren't going to get too much further but a change from 57" to
52" can be done with an extended session of 15 micron.
You want to be doing spherizing strokes a lot more than the hogging out
strokes so that when you go and polish, the mirror will polish out without
too much trouble.  If you must, get the ROC down to about 54" with the 15
micron and make sure that the mirror gets throughly sperized with the short
strokes with 2-3 wets before going to the final grit and after that first
wet, make sure that the whole mirror is getting ground at that grit (do the
light reflection test for looking at that) and you should be good to go.
You can lose about 1/2 to an inch in polishing and figuring without too much
trouble.
Bob May
http://nav.to/bobmay
bobmay@nethere.com
NEW! http://bobmay.astronomy.net