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 (Martin)]

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 (Martin)]

Look at these websites.
http://www.mtbparker.com/MirrorWorks...ctorStory.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 (Geoff)]

Originally Posted by 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.

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.