Archived posting to the Leica Users Group, 1998/10/01
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Hi Jim- >Who made the glass for the Hubble Space Paper Weight? jh I don't know, but I dimly remember that they made the glass for the 100" mirror in the Palomar Observatory, years ago, when I was still a youngster. BTW: It wasn't Corning's fault that the Hubble Telescope mirror was not ground correctly. All they did was to furnish the glass. Further, I would suspect that the optical quality of the glass in the Hubble wouldn't be the same as that used in camera lenses. The glass is made with rigidity and with minimal distortion from thermal variations foremost in the calculations. After a large telescope mirror has cooled, it is ground to specifications. Then, it is silvered, coated and recoated - - as it is a *reflective* surface - - not a "pass through" lens. The grinding, silvering and coating processes give a large-diameter mirror the capability to produce the results we see in our searches of the universe. Let's not confuse the "pass through" characteristic of superb optical glass with the "hard as granite" characteristic of the glass used as the bedrock of astronomical mirrors. George Berger gberger@his.com