October 2nd, 1608/October 3rd, 1947...optics/telescope

Wired...

October 2nd, 1608:

...officials in the Netherlands pondered over a patent application. It was submitted by spectacle-maker Hans Lippershey for a "device by means of which all things at a very great distance can be seen as if they were nearby." This is the earliest known record of a telescope. A few months later, scientist Galileo Galilei would get his hands on one.

October 3rd, 1947:

After 13 years of grinding and polishing, the Palomar Observatory mirror is completed at Caltech.

The mirror began as a 20-ton piece of molten Pyrex, a new glass blend, at the Corning Glass Works in upstate New York. Pyrex expands and contracts far less than regular glass, making it less prone to distortion, a problem that plagued the 100-inch mirror already in operation at Palomar.

After being heated to 2,700 degrees Fahrenheit, the Pyrex was poured into a ceramic mold and cooled at an average rate of one or two degrees per day until it reached room temperature 11 months later. After that it was shipped west to Caltech in Pasadena, where the glass was painstakingly ground to perfection in a process lasting more than a decade.

Hans Lippershey


Palomar Observatory