the mirror that collects and focuses the incoming light in a reflecting telescope
Examples of 'primary mirror' in a sentence
primary mirror
The telescope's 'eye', its primary mirror, will be 40m in diameter and will gather 15 times more light than the largest optical telescopes operating today.
Times, Sunday Times (2011)
Its primary mirror will be 40m in diameter and gather 15 times more light than othertelescopes.