Q. How were the bricks removed from the mold for the 200" disk mirror now at Mt. Palomar?

Hello! Thank you for your question. Dr. George McCauley, who designed and supervised the casting of the 200-inch mirror, explains, "Removing the cores from the ribs of the disk and cleaning its surface is accomplished with a sharp-edged bar and a sandblast and presents no great problem; except, of course, great care must be exercised, if a bar is used, that the glass be not struck too severely. Removing the cores with a bar must be classed more as work than as a problem. The sandblast works slower, with more dust, but easier, and is ideal for cleaning the entire surface that has been in contact with the mold (McCauley, George V. "Some engineering problems encountered in making a 200 inch telescope disk." Bulletin of The American Ceramic Society 14, no. 9, Sept. 1935, 300-322).

Online Resources

There are several resources on The Corning Museum of Glass website and elsewhere online that might be of interest to you:

• "The Glass Giant," All About Glass, The Corning Museum of Glass, October 3, 2011.
• "The Hale Reflecting Telescope at Palomar," All About Glass, The Corning Museum of Glass, December 1, 2011.
• "Mirror to Discovery: The 200-Inch Disk and the Hale Reflecting Telescope at Palomar," Exhibition, The Corning Museum of Glass, January 10 to October 30, 2011. Includes slideshow of images of the manufacture of the disk.
• "Reflections on Glass: Telescope Mirrors," All About Glass, The Corning Museum of Glass, October 25, 2011.

Research Guide

"The 200" Disk and the Hale Reflecting Telescope," Rakow Research LIbrary, The Corning Museum of Glass.

Selected Print Resources

Books

• Florence, Ronald. The Perfect Machine: Building the Palomar Telescope. New York: Harper Collins, c1994.
• Woodbury, David Oakes. The Glass Giant of Palomar.  New York: Dodd, Mead & Company, 1953.
• Wright, Helen. Palomar, the World’s Largest Telescope. New York: MacMillan, 1953.

Articles

• diCicco, Dennis. "The Journey of the 200-Inch Mirror." Sky & Telescope 71, no. 4 (April 1986): 347-348.
• Learner, Richard. "The Legacy of the 200-Inch." Sky & Telescope 71, no. 4 (April 1986): 349-353.
• Rhodes, Richard. "Reflected Glory: How They Built Palomar." American Heritage Invention and Technology 1, no.1 (Summer 1985): 12-21.

Borrowing Library Materials

If you wish to borrow copies of library items, please contact your local library. The Rakow Research Library will lend designated books from its collection and will send copies of articles requested by other libraries. Your library can request items through the OCLC WorldShare Interlibrary Loan (ILL) system or by direct request through email at ill@cmog.org. For more information, please see our ILL policies and procedures.

Please let us know if there is anything specific that we could assist you in finding.