Re: ATM BVC Glass

["Dave McCarter" <dmccarter@sympatico.ca>]

> Has anyone had any good/bad experiance with BVC glass in the 14"-20" size.
> Any feedback is welcome.
> Sam Orawski
> Hamilton Canada

Hi Sam. At Starfest we had a 16 inch dobsonian telescope belonging to RASC
London Centre member John Bontji. I did the polishing and figuring on the
mirror, and John did the rest. And what a scope!

The soft glass polishes quickly, but you still need to put in the hours to
rid the edge of pits. Figuring must be done with very soft pitch, preferably
needing rechanneling every fifteen or so minutes. Yes, soft. I polished with
CeO and figured with extremely fine rouge. The surface is exceptionally
smooth, and in the star test with a 240 line per inch Ronchi  the straight
bands just fall off the edge. We are very happy with how the scope works.

Dave