position micrometer
now rare
noun
An apparatus for measuring the position angle of one celestial object relative to another, containing a thread or wire mounted at the common focus of the objective lens and eyepiece of a telescope, which can be rotated in a plane perpendicular to the axis of the telescope; an apparatus similarly used with a microscope.
Origin
Mid 19th century; earliest use found in The Penny Cyclopaedia.
- keep one's hands clean
- keep one's head
- keep one's head above water
- keep one's head down
- keep one's mouth shut
- keep one's nose clean
- keep one's nose out of
- keep one's nose to the grindstone
- keep one's own counsel
- keep one's powder dry
- keep one's side of the bargain
- keep one's word
- keep (or archaic bear) someone company
- keep (or eat) kosher
- keep (or hold) one's end up
- keep (or leave) one's options open
- keep (or lose) one's cool
- keep (or lose) one's temper
- keep (or lose) track of
- keep (or make) a House
- keep (or sleep in) a whole skin
- keep (or stand) guard
- keep (or stay) out of someone's way
- keep out (or keep someone/thing out)
- keep pace with