Giant Furnace Opens to Reveal 'Perfect' LSST Mirror Blank

Members of the team building the LSST, a large survey telescope being built in Northern Chile, gather to celebrate the successful casting of the telescope's 27.5-foot-diameter mirror blank.The LSST requires three large mirrors to give crisp images over a record large field of view. The two largest of these mirrors are concentric and fit neatly onto the large mirror blank shown here. Seated on the mirror (L-R): LSST Director Tony Tyson, LSST System Scientist Zeljko Ivezic, LSST System Engineer Chuck Claver, LSST Project Manager Don Sweeney. Image credit: Howard Lester / LSST Corporation