 | 1821 - 708 páginas
...the'sextant, and fix the index ; then, by altering a little the position of the instrument, make tlift image appear on the other wire ; if the contact still remains perfect, the axis of the telescope is in its right situation : but, if the limbs of the two objects appear to separate or lap over, at the wire... | |
 | Nathaniel Bowditch - 1826 - 732 páginas
...sextant, and fix tue. index, then, by altering a little the position of the instrument, make the ¡mage appear on the other wire ; if the contact still remains perfect, the axis of the telescope is in its right situation; but, if the limbs of the two object's appear to separate or lap over, at the wire... | |
 | Nathaniel Bowditch - 1826 - 764 páginas
...the sextant, and fix t indexa then, by altering n little the position of the instrument, make t image appear on the other wire; if the contact still remains perfect, the ;n •of the telescope is in its right situation; but, if the limbs of the two objet appear to separate... | |
 | Sir J. Butler Williams - 1846 - 368 páginas
...just at the wire of the telescope which is nearest the plane of the sextant (see diagram page 267), fixing the index, and altering the position of the...This adjustment is not very liable to be deranged." OP THE USE OP THE SEXTANT. The large sextant is rarely required for observations (on land) of terrestrial... | |
 | Nathaniel Bowditch - 1846 - 854 páginas
...plane of the sextant, and fix the index; then, by altering a little the position of the instruinrnt, make the objects appear on the other wire ; if the contact still remains ]>erli;ct, the axis of tlie telescope is in its right situation ; but, if the limbs of the two objects... | |
 | Basil Jackson - 1847 - 410 páginas
...more than the upper, so as to make his perpendicular diameter appear less than his horizontal one, which is that given in the "Nautical Almanac:" in...other wire : if the contact still remains perfect, the telescope is in proper adjustment ; if not, it must be altered by moving the two screws which fasten... | |
 | Benjamin Pike (Jr.) - 1848 - 482 páginas
...the Sextant. — This is known to be correct, when the sun and moon, having a distance of 90 degrees or more, are brought into contact just at the wire...This adjustment is not very liable to be deranged. Of the sextant, it has been said, that it is in itself a portable observatory ; and it is doubtless... | |
 | Benjamin Pike - 1848 - 356 páginas
...the Sextant. — This is known to be correct, when the sun and moon, having a distance of 90 degrees or more, are brought into contact just at the wire...This adjustment is not very liable to be deranged. Of the sextant, it has been said, that it is in itself a portable observatory ; and it is doubtless... | |
 | John William Norie - 1852 - 844 páginas
...plane of the sextant, and fix the index ; then, by altering a little the position of the instrument, make the objects appear on the other wire. If the contact still remain perfect, the axis of the telescope is in its right situation ; but if the limbs of the two objects... | |
 | Elias Loomis - 1855 - 514 páginas
...is nearest the plane of the sextant. Fix the index, and alter the position of the instrument so as to make the objects appear on the other wire. If the...This adjustment is not very liable to be deranged. (133.) To measure the altitude of the sun by reflection from mercury. Set the index near zero. Hold... | |
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... to make the objects appear on the other wire ; if the contact still remains perfect, the axis of the telescope is in proper adjustment ; if not, it must be altered by moving the two screws which fasten, to the up-and-down piece, the collar into which... 
