In most large telescopes, a large primary mirror captures light and reflects it off one or two secondary mirrors to the telescope's instruments. (sciencemag.org)
Each of the telescopes has a 0.5 - m primary mirror and similar equipment. (projectsolaris.eu)
Early preparation for construction has included groundwork at the mountaintop site at Las Campanas in northern Chile, and initial fabrication of the telescope's seven enormous primary mirror segments.» (uanews.arizona.edu)