What is a G2 glass lens mae of ?

[Fritz The Cat]

I did some research and have not found the specifications of G2 glass lens . Is it the glass or the coating that gives G@ glass lens its property?

Please understand I grind and polish my own telescope mirrors and am not afraid to take on grinding a small lens. Now the coating I don't think I can do.

So has anyone measured the focal lenght of some of these lens. :thinking:

Edit : I'm back , I found some references about focal lenght and diameter of lens. I found two sizes ,6 mm about and 9 mm about . The thread said one could get a better beam with one when the focal lenth was a couple of MMs longer . Why not use laeger lens like 12 mm or more ? What focal lenght would be goo to start with ? Thanks for your input ,

 

[shokkunlasers]

both of course

1. its glass as the name says the shape of the lens is asspherical / near to impossible to grind it by hand /

2. the coating only reduces how much light of a certain wavelength range gets reflected from the surface of the lens idk which is used on the g2 proably MgF2 for 300nm-700nm

if you want to make a lens ... buy it! you can't grind BK7 optical glass with normal tools asspecially no asspherical ones

 

[Blord]

Cool that you grind and polish your own telescope mirrors. It is for the Dobson telescope I suppose.
Just curious. What is the largest size mirror you have made ?

 

[Fritz The Cat]

I've completed an 8" f7 Newtonian . Thats a 57 inch focal length with a 12 mm eyepiece that gives me a plus100x view Its mounted on a pipe fixture along the equatorial lines. With a cement base it weights over 250 lbs . My favorite magnification is about 100x plus. I was able to view planetary detail back in 1988 when Mars was very close. I can also split saturns rings and see cassinis divion which is about .5 arc seconds . (i think?)e 'large" completed an 12.5 inch f5 mirror which needs a little optica polishing and eeds a telescope tube.http://l

In addition about dozen small telescopes 6 inchs and under for friens .

I also ground a ruby rod on diamond wheels. Its about 2.5 incjhs long about the thickness of a pencil . Laser anyone ?

I', going to hook up a Laser ,green , to my 8 inch telescope to assist my finder scope.

Amatuer telescope makers have tackled small asspherical lens by first grinding and polishing the lens and tool at the same time. Once you have two perfect spherical sufaces to start polishing the lens with special lapping tools to change it from a sphere to a parabolodal surface or any othe revolved curved line suface. You can measure the amount of correction with a newtonian interferometer and a monochromatic light source using the perfect tool l . Simple once you have done it ,hard to explain . I expected a nay sayer anyways no problem