Refracting telescopes dominated the nineteenth century ... correct for phase differences by using optical path-length compensators, and then combine the beams so as to form an interferogram ...

To discuss your specific telescope project optical requirements with the Optical ... With such stable conditions testing, particularly with long path lengths, becomes quantifiable and reliable.

[Bill Hammack] elaborates on one such piece of engineering: The Alignment Optical Telescope. The telescope was used to find the position of the Lunar Module in space so that its guidance computer ...

Telescopes are devices used to observe the universe. There are many different types and some are even sited in space. Optical telescopes close optical telescopeA device used to see distant objects ...