[ATM] Rough grinding 8" Mirror spreading the curve...

[bobmay at nethere.com (Bob May)]

When you look at where you have been grinding, you will see that indeed the
center of the mirror will be the area where the ground surface will be.  Be
careful that you don't go too far for the curvature or you will be having to
invert the tool and mirror to obtain the ROC that you want.
Remember that you are just digging out a hole in the glass right now and you
don't want to do too much on the edges otherwise you will just be removing
glass for no real valid reason.
You also want to stop using the coarsest grit well before you get the ROC
desired as the coarser the grit, the deeper the cracks you get from the
grinding process and thus the more glass that needs to be removed.
Bob May
http://nav.to/bobmay
bobmay@nethere.com
NEW! http://bobmay.astronomy.net