 | Balfour Stewart, William Winson Haldane Gee - 1885 - 316 pages
...lines already mentioned crossing the centre of the field of view at right c Pig. I3a.— BINO WITH CROSS-THREADS. angles to each other. The cross-wires...cross-wires to the axis of the telescope (see Fig. 1 3a). The instrument ought to stand on a block of stone firmly fixed to the earth and free from the... | |
 | Balfour Stewart - 1912 - 376 pages
...lines already mentioned crossing the centre of \he field of view at right c Fig. 130..—RING WITH CROSS-THREADS. angles to each other. The cross-wires...fixed on a disc of metal somewhat smaller than the telescope-tube. It is held in position by four small screws, which permit the exact adjustment of the... | |
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CROSS-THREADS. angles to each other. The cross-wires are fixed on a disc of metal somewhat smaller than the telescope -tube. It is held in position by four small screws, which permit the exact adjustment of the intersection of the cross-wires to the axis... 