from The Century Dictionary.
- noun A micrometer for measuring angles of position (see
angle of position, under position), which are read upon a graduated circle.
Sorry, no etymologies found.
It would be out of place to describe here the practical adjuncts of a modern equatoreal -- the adjustments for pointing it, the clock for driving it, the position-micrometer and various eye-pieces, the photographic and spectroscopic attachments, the revolving domes, observing seats, and rising floors and different forms of mounting, the siderostats and coelostats, and other convenient adjuncts, besides the registering chronograph and numerous facilities for aiding observation.