The elements of astronomy; a textbook . s into the eye end of the telescope. It usuallycontains a set of fixed wires, two or three of them parallel toeach other (only one, e, is shown in Fig. 149, which represents 1 For the EquatoriaL Coud6, Siderostat, and Coelostat see Arts. 557.,and 558, 412 APPENDIX. [§542 the internal construction of the instrument), crossed at rightangles by a single line or set of lines. Over the plate whichcarries the fixed threads lies a fork, moved by a carefully made screw with a graduatedhead, and this fork carriesone or more wires parallelto the first set, so that
The elements of astronomy; a textbook . s into the eye end of the telescope. It usuallycontains a set of fixed wires, two or three of them parallel toeach other (only one, e, is shown in Fig. 149, which represents 1 For the EquatoriaL Coud6, Siderostat, and Coelostat see Arts. 557.,and 558, 412 APPENDIX. [§542 the internal construction of the instrument), crossed at rightangles by a single line or set of lines. Over the plate whichcarries the fixed threads lies a fork, moved by a carefully made screw with a graduatedhead, and this fork carriesone or more wires parallelto the first set, so that thedistance between the wirese and d, Fig. 149, can beadjusted at pleasure and read off by means ofthe scale that is shownand the screw-head grad-uation. The box, B, , containing the wiresand micrometer, is so ar-ranged that it can itselfbe rotated around the op-tical axis of the telescopeand set in any desired position, — for example, so that the movable wire d shallbe parallel to the celestial equator. When so set that the. Fig. 148. — The Filar Position-Micrometer.
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Keywords: ., bookcentury1900, bookdecade1910, booksubjec, booksubjectastronomy
