grinding lenses

[Jarrod]

ive been thinking about one of the methods used to grind mirrors: using two equal sized pieces of glass. when the glass used as the 'tool' ends up with a convex surface, would it be possible to turn the tool into a lens? obviously it would be of much poorer quality then a lens made of proper optical quality glass, but is it possible?

jarrod.

PS, sorry about all the strange questions, im still new to this subject.

[mill]

As i understand it, you will need flint and crown glass to make a proper lens.
It has something to do with the different lightpaths thru the glasses that makes it work.

[Jarrod]

Okay, so it wouldent work with the glass used to create mirrors. but if you you had high quality glass, would it work?

jarrod

[mill]

Look at these websites.
http://www.mtbparker.com/MirrorWorkshop/refractorStory.html
http://bobmay.astronomy.net/refractor/Refrindex.htm
BK7 is the glass you can use to make the lens and F2.
BK7 is also used in some reflector scopes.
The bottom site is a very good site to learn lens making.

[Geoff45]

Yep, it's possible, but as you say it won't be much good for anything. The quality of the glass in not so much a problem as is the fact that with any simple lens you will get chromatic aberration and spherical aberration, no matter how good the quality of the glass.