"Perfect" Mirrors Cast For LSST

eldavojohn writes "The Large Synoptic Survey Telescope (which was partially funded by Gates & Co.) announced a world record casting for its single-piece primary and tertiary mirror blanks, cast at the University of Arizona. From the announcement: 'The Mirror Lab team opened the furnace for a close-up look at the cooled 51,900-pound mirror blank, which consists of an outer 27.5-foot diameter (8.4-meter) primary mirror and an inner 16.5-foot (5-meter) third mirror cast in one mold. It is the first time a combined primary and tertiary mirror has been produced on such a large scale.'"

No such thing as "perfect"...

[QuietLagoon]

... perfection is only a limitation of the measurement process used to find flaws.

Re:No such thing as "perfect"...

[QuietLagoon]

But then the question becomes: is measurement at the atom level really good enough? Or is it accepted as good enough only because we can do no better?

Re:Apparently...

[ffoiii]

If only we knew who invented it... Sometimes I just wish things had names that described what they were or how they worked rather than who invented it. Credit where credit is due but isn't the value of a thing in it's use rather than it's discoverer?

Re:Can someone explain...

[mapsjanhere]

hmm, I think you did a d^2 instead of an r^2 in your area calculations. The actual area is 55 m^2. With glass density around 2.5 g/cm^3 you get about 20 cm thickness. What's an astonishing aspect ratio, about the shape of a saucer.