The Hale Telescope 200-inch Pyrex primary mirror blank was cast on 2 December 1934 at Corning Glass Works in Corning NY under the direction of George McCauley. The disk remained in the oven at pouring temperature for just over a month and then was gradually cooled over a period of ten months. This slow cooling (“annealing”) gave the cooling glass the time to mechanically relax and minimize residual internal stresses, but it also gave McCauley an extended opportunity to personally check on the cooling progress daily. On 26 March 1936 the mirror blank began its 16-day trip by rail from Corning to the Caltech Optical Shop in Pasadena CA. The well-type rail car that carried the blank was transported 3400 miles west over NYC, CCC&StL, CBQ, and ATSF railroads. The 200-inch telescope project captured the public’s imagination, and all across the country thousands of people waited along the train route to watch the huge mirror pass. The priceless cargo arrived safely at Pasadena on 10 April 1936.
Under the direction of John A. Anderson and Marcus H. Brown at Caltech, the mirror blank was ground and figured into the desired paraboloid shape. As delivered to Caltech the mirror blank had a mass of 20 tons (18 tonnes) and when it left Caltech the nearly finished mirror had a mass 14.5 tons (13 tonnes). Including delays for World War II the mirror disk spent 11 ½ years at Caltech.
The long-awaited mirror arrived at Palomar 19 November 1947. It was transported by Belyea Truck Company of Los Angeles by flatbed trailer towed by a single lead truck with two additional trucks rigged to assist by pushing the trailer from behind. The mirror convoy climbed the steep ascent up Palomar Mountain on San Diego County Road S-6 (at the time known as the “Highway to the Stars”).
Mirror transit slideshow. Click to start. Use < or > to reverse or advance one slide, or the progress dots to jump slides (this pauses the slideshow). Click any image to enlarge and on some captions for further context. The slideshow will pause for videos.
A. Boden and A. Mejía.
This collection of images and video footage came from three main sources: The Corning Museum of Glass shared with us their holdings on the pouring of the blank and rail transport arrangements made out of the east coast. Many of the Pasadena images are from Caltech's own collection, which is largely available through the Caltech Archives. The Archives is also the main source of vintage Palomar footage. The third set of images related to the mirror transport to Palomar was graciously donated to us by the Belyea Truck Company and the family of Mr. Jack Belyea, who was a long-time transportation services partner with Palomar/Caltech. Specific thanks go to Mr. Belyea's daughter J. Jones and granddaughter T. Hixson.
