The American practical navigator : being an epitome of navigation and nautical astronomy (1888)
Bowditch, Nathaniel, 1773-1838, United States. Navy Dept. Bureau of Navigation, Cooper, Philip Henry, 1844-1912 · Washington : Govt. Print. Off. · leaf 113
on has been determined,the value of one division of its micrometer-head becomes also known. It is desirable that the sum of the azimuthalcorrections for the circumzenith-stars nearly balance, and that for any two zenith-stars the mean of the tangents oftheir declinations equals the tangent of the… … Art. 199. Fig. 56 represents a modified form of the portable transit, the broken-backed or prismatic,instrument, which is rapidly coming into favor owing to the great facility with which it can be used. It is either azenith telescope, or a transit instrument, and possesses the excellent feature of…
Navigation · Nautical astronomy
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