Lockyer, Norman, Sir, 1836-1920, Seabroke, G. M. (George Mitchell), 1848-1918 · London, Macmillan and co. · leaf 260
we must see that the line of sight is exactly at rightangles to the axis on which the telescope turns, and when CHAP. XVI.] THE TRANSIT CIRCLE. 237 we have satisfied ourselves of that, we must, in thesecond place, take care, not only that the pivots on whichthe telescope rests are perfectly equal… … IlG. 114.—Transit Instiuiia-ut iua tixed Observuioiy. through the zenith. Then, thirdly, if we take carethat one end of this axis points to the east, and theother to the west, we shall know, not only that ourtransit instrument sweeps through the zenith, but sweepsthrough the pole which happens to…
Astronomy · Telescopes
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