why do trace and soho telescopes use special mirrors ?
The largest optical telescope in the world as of 2009 to use a non-segmented single - mirror as its primary mirror is the 8.2 m ( 8.7 yards ) Subaru telescope of the National Astronomical Observatory of Japan , located in Mauna Kea Observatory on Hawaii since 1997 ; however , this is not the largest diameter single mirror in a telescope , the U.S. / German / Italian Large Binocular Telescope has two 8.4 m ( 9.2 yards ) mirrors ( which can be used together for interferometric mode ) .