Re: Palomar Observatory Mirror Blank Delivery 5/12/1936

Bruce Smith

Ben, Folks,

A neat story that I had not heard of before.  I found some additional on-line and photos information. 

The history of the telescope can be found at:

The mirror blank was cast by Corning Glass Works in Pyrex, which was new at the time.  The first attempt at pouring the mirror occurred in March 1934, with great fanfare, and it failed.  That mirror is apparently on display at Corning.  The second attempt, done quietly on December 2, 1934, was successful.  The blank was annealed for 10 months and the oven was opened on October 25, 1935.  On March 25, 1936, the blank was loaded onto NYC S-499010 and departed for CalTech. There are reports that the train’s speed limit was 25 mph 

See for a video showing the loading of the mirror onto the flat car and the train in motion, as well as the impact of the mirror as it traveled across the country.  Note that the video is an archaic Quick Time format and so you may need to download or tweak some of your computer’s tools.

The blank arrived at East Pasadena on April 10, 1936.  From there it was hauled by truck to CalTech.

The mirror would require 10 years of grinding and preparation before it was ready to be moved and installed at Mount Palomar, in part because of the demands of WWII on manpower.  In October 1947, the mirror was moved by truck to Mount Palomar to be installed in the telescope named after it’s creator, George Ellery Hale who had died 10 years previously.

From conception to completion, this project took 20 years!  So the next time you hear someone complaining about science not producing results instantly, think about the dedication of the folks who saw this project through. 



Bruce F. Smith            

Auburn, AL

"Some days you are the bug, some days you are the windshield."

On Feb 18, 2016, at 9:50 AM, STMFC@... wrote:

Catching up on historical society pubs and came across John Signor's "Santa Fe and the Stars" in the 3rd Quarter 2015 issue of the SFRH&MS Warbonnet documenting the delivery of a 200" mirror blank from Pyrex via Santa Fe Extra 3157 on May 12, 1936.  Consist as follows:

ATSF 3157 (2-8-2)
NYC 121195 (Lot 559-B USRA-design steel boxcar)
NYC 499010 (Lot 273-F well flat)
ATSF 1680 (Caboose)

Article includes four photos showing the delivery of the mirror blank.

Ben Hom 

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