| altazimuth |
a telescope or other instrument that moves in altitude (up and down) and in azimuth (back and forth). |
| binary star |
two stars orbiting around a common center of gravity and often appearing as one to the unaided sight or through a telescope; double star. |
| collimate |
to accurately adjust the line of sight of (an optical instrument such as a telescope). [1/2 definitions] |
| collimator |
a small telescope that is fixed to a larger one and is used to align it accurately. [1/2 definitions] |
| equatorial |
a telescope mounted on two axes, one parallel to and one perpendicular to the earth's axis of rotation. [1/3 definitions] |
| eyeglass |
an eyepiece, as on a microscope or telescope. [1/4 definitions] |
| eyepiece |
the lens or lenses in an optical instrument, such as a microscope or telescope, through which one views the object or image under scrutiny. |
| field glass |
(usu. pl.) a compact, portable binocular telescope used esp. outdoors. |
| lens |
a complex of such pieces, as in a camera or telescope. [1/3 definitions] |
| magnification |
the power or extent of magnifying, as of a telescope or microscope. [1/2 definitions] |
| reflecting telescope |
an optical telescope that uses mirrors rather than lenses to focus light rays. (Cf. refracting telescope.) |
| reflector |
a reflecting telescope. (Cf. refractor.) [1/2 definitions] |
| refracting telescope |
an optical telescope that uses lenses rather than mirrors to focus light rays. (Cf. reflecting telescope.) |
| refractor |
a refracting telescope. (Cf. reflector.) [1/2 definitions] |
| scope |
a telescope, microscope, or the like. [1/4 definitions] |
| sight |
a device, as on a gun or telescope, that enables accurate aiming. [1/11 definitions] |
| speculum |
one of the mirrors in a reflecting telescope or other optical instrument. [1/3 definitions] |
| spyglass |
a small hand-held telescope. |
| surveyor's level |
an instrument for measuring elevation, consisting of a tripod on which are mounted a horizontally revolving telescope and a spirit level. |
| telescope |
to slide or force together (the tubes of a hand telescope or the like), often in sections that fit inside one another. [1/7 definitions] |
| telescopic |
of or relating to a telescope. [2/4 definitions] |