A complete collection of tables for navigation and nautical astronomy. With simple, concise, and accurate methods, for all the calculations useful at sea; particularly for deducing the longitude from lunar distances, and the latitude from two altitudes of the sun and the interval of time between the observations / By Joseph de Mendoza Rios.

  • Mendoza y Riós, José de, 1763-1816.
Date:
1809
Catalogue details

Licence: Public Domain Mark

Credit: A complete collection of tables for navigation and nautical astronomy. With simple, concise, and accurate methods, for all the calculations useful at sea; particularly for deducing the longitude from lunar distances, and the latitude from two altitudes of the sun and the interval of time between the observations / By Joseph de Mendoza Rios. Source: Wellcome Collection.

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    Aux.Arg. App. alt. % App. alt. ]) 'Sum of app. alt. 33 • 24 50- 59 (lior- parallax 54'. 59) 84. 23 N. I. 23'- 10 Compl. corr. :?f’s alt. + 58 34 + 27 Correfl;. 3) ’s alt. + 33 14 + 0 Prop, part - + 37 23 37 Correded fiim of alt. - - 85. 55 25 N. II. l_App. diftance Referved fee. Corr. diftance True diftance Diftarices. May 6 at Greenwich 64 63 • 52 47l 29 N. III. N. IV. 03264 30 88315 169 67753 T34 at 9“ at 12 63 64 63 10'' 53 47 17 49 16 S3 47 7® Diff. DifF. P. L. 54 37 6 App. time at Greenwich ( + 9'’) - By Nautical Almanac, for that time, the Sun’s right afeenfion is By Table XXII. the right afeenfion of the Virgin’s Spike is and the declination of the fame ' P.L. 5179s P.L. 30055 (diff.) 21740 2* ^3 I o' (fum) 59664 538 126 '■ 56’. 15“ •14-23 . 4' , 50 S. *’s polar diftance - 79°. 55'. lo L. cofec. 0.00675 Ship’s latitude - 23 . 12 . 0 L. fee. 0.03662 x’s altitude - 33 . 22 . 44 - Sum - 136. 29 . 54 Half-fum - 68 . 14 . 57 L. cofine 9.56886 Half-fum—alt. - 34 . 52 . 13 L. fine 9-757'9 *’s horary angle - 3'\ 5i‘. 30* L, verf. (fum) 9.36942 *’e right afeenfion - 13 • 14 • 23. Right afeenfion of mid-heaven (diff.) 9 . 22 . 53 O’s right afeenfion 2 . 56 . 15 App. time at the ftiip (diff) 6. 26 . 38 App. time at Greenwich lo . 49 . 7 Longitude of the Ihip (diff) 4 . 22 . 29 2t65“. 37' Weft. SCHOLIUM I. In the preceding rules we find the apparent time at the Ihip, when the diftance was obferved by means of the Sun’s altitude, obferved at the fame time : but the apparent time may likewife be afeertained by means of an altitude taken before or after, in order to know the error of the watch in the meridian of that obfervation. Allowine: for that error, as well as for a proportional part of the rate of the watch in the interval, if both are confiderable, the apparent time at the moment of obferving the diftance will be. eafily concluded ; and, by comparing it with the apparent time at Greenwich, as explained be- fore, the refult will be the longitude of the place, where the altitude for afeertaining the apparent time was obferved. In fuch cafes the Sun’s altitude may be obferved in the circumftances moft advantageous for determining the time, either before or after the obfervation of the diftance. This method will be particularly ufeful, when the Sun’s altitude, obferved with the diftance, is difadvantageous, and when the diftance is to a ftar, as the obferved altitude may then produce confiderable error in the computed time, though it may be fufficiently accu- rate for the calculation of^the true diftance. EXAMPLE I. December 6, i793» latitude 53°. 29^ S. longitude 170° W. by account, about no''. 20’, the followina; altitudes of the Sun’s lower limb were obferved: what was the error of the