Primary mirror

Six of the 18 primary mirrors of the James Webb Space Telescope being prepared for acceptance testing.
The correctly ground backup primary mirror built by Eastman Kodak for the Hubble space telescope (the mirror was never coated with a reflective surface, hence its honeycomb support structure is visible). It now resides in the National Air and Space Museum in Washington, DC.[1]
The largest non-segmented mirror in an optical telescope in 2009, one of the Large Binocular Telescope's two mirrors.

A primary mirror (or primary) is the principal light-gathering surface (the objective) of a reflecting telescope.

  1. ^ "Mirror, Primary Backup, Hubble Space Telescope". Smithsonian - National Air and Space Museum. 2007-08-28. Archived from the original on 2007-10-13. Retrieved 2008-04-26.