A primary mirror (or primary) is the principal light-gathering surface (the objective) of a reflecting telescope.
Read more about Primary Mirror: Description, Superlative Primary Mirrors
Famous quotes containing the words primary and/or mirror:
“But the doctrine of the Farm is merely this, that every man ought to stand in primary relations to the work of the world, ought to do it himself, and not to suffer the accident of his having a purse in his pocket, or his having been bred to some dishonorable and injurious craft, to sever him from those duties.”
—Ralph Waldo Emerson (1803–1882)
“At first, it must be remembered, that [women] can never accomplish anything until they put womanhood ahead of wifehood, and make motherhood the highest office on the social scale.”
—“Jennie June” Croly 1829–1901, U.S. founder of the woman’s club movement, journalist, author, editor. Demorest’s Illustrated Monthly and Mirror of Fashions, pp. 24-5 (January 1870)