The 2.4-metre Hubble Space Telescope (HST) primary mirror nears completion at Perkin-Elmer's Optical Facility at Wilton, Connecticut. The mirror has j Stock Photo - Alamy
Large Zenith Telescope - Wikipedia
Amazon.com : Focal Length 900Mm,Finder Mirror 5X24,Telescope Refracting Telescope Adjustable Portable Travel Telescopes for Astronomy,Multi-Layer Green Film,Electric : Electronics