158-inch mirror blank

The 158-inch mirror blank (now the 4-meter) upon its arrival at KPNO. In the picture from left to right are Dr Dave Crawford, Mr Dinsmore, unidentified, unidentified, Mr Jim Miller. December 1971. (Note: although the original design called for a 150-inch mirror, it was cast rather larger and cut back to 158 inches, which was the largest the mirror could be over the design size and still fit the telescope.)