The 200" Disk and the Hale Reflecting Telescope: Archives and Special Collections

Dr. George V. McCauley designed and supervised the casting of the 200-inch mirror for the Mount Palomar, Calif. Telescope.

Dr. McCauley was a Corning Glass Works physicist. In June 1918, he began his 29-year employment at Corning Glass Works. He supervised the casting of the famous 200-inch disk for the Hale Observatory at Mount Palomar in 1934. This was the world's largest until the early 1970s. There were several large-sized mirrors cast by Corning Glass under the direction of Dr. McCauley. The next largest ones are in telescopes at the Lick Observatory at Mount Hamilton, California (120 inches) and the Hale Observatory at Mount Wilson, California (100 inches).

Archive includes articles (including articles by McCauley), research notes, newspaper clippings, correspondence, photographs, diagrams and glass slides.

Dr. John Cylde Hostetter, director of Research and Development at Corning Glass Works during the creation of the 200 inch disk, was born on February 18, 1886, in Williamsport, PA. He studied chemical engineering at Bucknell University, where he received a BS in 1908 and an MS in 1909.

Before coming to Corning Glass Works, Hostetter worked as a chemistry instructor at Bucknell University (1908-10), as a chemist at the US Standards Bureau (1910-12), and as a physical chemist at the Geophysical Lab of the Carnegie Institute (1912-19). In 1919, he joined the Corning Glass Works as manager of the Steuben Division. He served in a variety of other positions at Corning as well, including assistant to the vice president (1922-24), manager of the company's Rhode Island division (1924-28), and manager of its bulb and tubing department (1928-30). In 1930, he became director of research and development, a post he filled until 1937. From 1931 to 1936, he directed the task of casting the 200 inch disk.

After leaving Corning in 1937, Hostetter became vice president and director of research at Hartford-Empire Co., where he remained until 1944. From 1944 to 1949, he served as president of the Mississippi Glass Co, and was on the board of directors of Welsh Refractories Corporation from 1944 to 1950. In 1950, he retired to Winter Park, Florida, having received a variety of awards for his contributions to science during his career. He died on April 2, 1962.

The bulk of this collection consists of approximately 185 photographs, documenting the creation by Corning Glass Works of a 200 inch glass disk, which became the mirror of the Hale telescope. Although John Hostetter collected these photographs, they were taken by others, including Ayres A. Stevens of Corning, NY. Some duplicate or are similar to photographs in the George McCauley Papers. The collection also includes a small amount of personal and glass-related miscellany from John Hostetter.