• A reflection of David at the Mirror Lab window
  • David at the introductory talk
  • Our tour guide (Gerry) talks us through the process of making an 8+ meter mirror
  • Elizabeth, and our tour group, looking down at the mirror casting turn-table
  • Some of the hardware to prepare the turntable to make a mirror
  • More of the hardware
  • These forms create the hollows in the final mirror (the glass will be above and inbetween them)
  • An example of the final honeycomb mirror
  • This is the turntable oven which will melt the glass into the rough shape of the mirror
  • This entire turntable will spin at about 7 RPM while the glass is heated to melt and form the rough shape of the mirror. This spin-casting technique in unique to the Steward Observatory Mirror lab.
  • This is the lid and heater that sits on top of the turntable to melt the glass
  • This mirror has been cast and the back has been ground flat
  • It will next be moved into the grinding and polishing room
  • A panorama of the grinding and polishing room. The mirror in the foreground is one of the 7 mirrors, each 8.4m in diameter, that will create the 24.5m (80.4 ft) primary mirror of the Giant Magellan Telescope.
  • Our guide with the LSST mirror behind him
  • The primary (M1) and tertiary (M3) mirrors (for the Large Synoptic Survey Telescope) were cast as a single 8.4-m blank. The inner part will become a 5-m f/0.8 tertiary mirror, while the outer part 5.0 to 8.4-m diameter will be an f/1.25 primary mirror
  • This frame is used to measure the mirror with an interferometer to find its precise geometry. Alternate measurements and polishing achieve the final product.
  • After the mirror is ground to approximately the correct geometry, it is polished here. The mirror revolves (at varying speeds depending on how much glass needs to be removed) as the polisher removes glass.
  • The mirror polisher in action
  • A piece of the Ohara E6 borosilicate glass used in these mirrors