Astronomy, a handy manual for students and others (1918)
Dyson, Frank Watson, Sir, 1868-1939 · New York, E.P. Dutton & Co. · leaf 91
d the observer lookingthrough the eye-piece of the telescope can examine it. So ASTRONOMY Position-Micrometer.—This examination usually in-volves measurement of some kind, and other instru-ments are required for this purpose. For example,to measure the distance between two very near starsor the… … Diag. XLIII. plane of the telescope. In Diagram XLIII, whichrepresents this instrument, there are three lines, AB,CC and DD, of which CC and DD can be movednearer or farther apart by means of screws P and Q,the distance between them being known from thereadings of the screw-heads. In addition the…
Astronomy
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