 | John Hamilton Moore - Nautical astronomy - 1810 - 662 pages
...observation with greater accuracy. The Adjustments of a Sextant are to set the index and horizonglasses perpendicular to the plane of the instrument, and their planes parallel to each other ; by the same method as the quadrant, only screwing on the plain tube or telescope ; also to set the... | |
 | Nautical astronomy - 1821 - 708 pages
...observation with greater accuracy. The adjustments of a sextant are similar to those of a quadrant: the index and horizon glasses must be perpendicular to the plane...parallel to each other when the index stands on 0 ; also the axis of the telescope must be set parallel to the plane of the instrument : each of these... | |
 | Nathaniel Bowditch - Nautical astronomy - 1826 - 732 pages
...observation with greater accuracy. The adjustments of a sextant are similar to those of a quadrant; the index and horizon glasses must be perpendicular to the plane...parallel to each other when the index stands on 0; also the axis of the telescope must be set parallel to the plane of the instrument: each of these particulars... | |
 | Frederick Walter Simms - Astronomical instruments - 1834 - 124 pages
...steadiness. Of the Adjustments. The requisite adjustments are the following: the index and horizon-glasses must be perpendicular to the plane of the instrument,...their planes parallel to each other when the index division of the vernier is at 0° on the arc, and the optical axis of the telescope must be parallel... | |
 | Nathaniel Bowditch - 1846 - 854 pages
...observation with greater accuracy. The adjustments of a sextant are similar to those of a quadrant; the index and horizon glasses must be perpendicular to the plane...parallel to each other when the index stands on 0 ; also the axis of the telescope must be set parallel to the plane of the instrument ; each of these... | |
 | Basil Jackson - Military reconnaissance - 1847 - 410 pages
...of great steadiness. OF THE ADJUSTMENTS. The requisite adjustments are the following: — The index and horizon glasses must be perpendicular to the plane...their planes parallel to each other, when the index division of the vernier is at 0° on the arc ; and the optical axis of the telescope must be parallel... | |
 | Benjamin Pike - Science - 1848 - 356 pages
...Of the adjustments. — The requisite adjustments are the following : the index and horizon-glasses must be perpendicular to the plane of the instrument,...their planes parallel to each other when the index division of the vernier is at 0° on the arc, and the optical axis of the telescope must be parallel... | |
 | Benjamin Pike (Jr.) - Scientific apparatus and instruments - 1848 - 482 pages
...Of the adjustments. — The requisite adjustments are the following : the index and horizon-glasses must be perpendicular to the plane of the instrument,...their planes parallel to each other when the index division of the vernier is at 0° on the arc, and the optical axis of the telescope must be parallel... | |
 | Sir Henry Edward Landor Thuillier - Surveying - 1851 - 826 pages
...steadiness. OF THE ADJUSTMENTS. THE requisite adjustments are the following : the index and horizon-glasses must be perpendicular to the plane of the instrument,...their planes parallel to each other when the index division of the vernier is at 0° on the arc, and the optical axis of the telescope must be parallel... | |
 | John William Norie - Nautical astronomy - 1852 - 844 pages
...the index. ADJUSTMENTS OF THE SEXTANT. To adjust a sextant is to set the index and horizon-glasses perpendicular to the plane of the instrument, and their planes parallel to each other when the index-division is at 0 on the arch ; also, to set the axis of the telescope parallel to the plane of... | |
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The index and horizon glasses must be perpendicular to the plane of the instrument, and their planes parallel to each other, when the index division of the vernier is at 0° on the arc ; and the optical axis of the telescope must be parallel to the plane... 
