A manual of spherical and practical astronomy, embracing the general problems of spherical astronomy, the special applications to nautical astronomy, and the theory and use of fixed and portable astronomical instruments, with an appendix on the method of least squares . ddle thread at the west transit,when it was again reversed, and, consequently, restored to itsfirst position. Cronstadt, August 16, 1843. East transit. West transit. b = -f 1.7 b = + 1.2 Circle S. ]Circle N.) Thread. Chronometer. Chronometer. I II III III II I 0* 20 18.50 22 56.0 26 9. 2* 950.52 7 16. 2 4 0.2 0 32.1 57 24. 0 29

A manual of spherical and practical astronomy, embracing the general problems of spherical astronomy, the special applications to nautical astronomy, and the theory and use of fixed and portable astronomical instruments, with an appendix on the method of least squares . ddle thread at the west transit,when it was again reversed, and, consequently, restored to itsfirst position. Cronstadt, August 16, 1843. East transit. West transit. b = -f 1.7 b = + 1.2 Circle S. ]Circle N.) Thread. Chronometer. Chronometer. I II III III II I 0* 20 18.50 22 56.0 26 9. 2* 950.52 7 16. 2 4 0.2 0 32.1 57 24. 0 29 Stock Photo
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The Reading Room / Alamy Stock Photo

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1159 x 2157 px | 19.6 x 36.5 cm | 7.7 x 14.4 inches | 150dpi

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A manual of spherical and practical astronomy, embracing the general problems of spherical astronomy, the special applications to nautical astronomy, and the theory and use of fixed and portable astronomical instruments, with an appendix on the method of least squares . ddle thread at the west transit, when it was again reversed, and, consequently, restored to itsfirst position. Cronstadt, August 16, 1843. East transit. West transit. b = -f 1.7 b = + 1.2 Circle S. ]Circle N.) Thread. Chronometer. Chronometer. I II III III II I 0* 20 18.50 22 56.0 26 9. 2* 950.52 7 16. 2 4 0.2 0 32.1 57 24. 0 29 38.0 32 45. b = — 2.7 b = — 1.6 The chronometer correction at 1* 15™ was + 40*.l; its daily rate, + 1*.74 on sidereal time. The stars place was 1* la™ 40.71 S = 59° 25 7.75 * Sawitsch, Fract. Aslron., Vol. I. p. 377. IN THE PRIME VERTICAL. 265 We find from the middle thread X = 3.9, cos P. = 1. The com-putation for the several threads may be arranged as follows: Diff. obsd. times S. Chron. Eate Diflf. obsd. times N. Chron. Rate 2t 2t log 6eci(t -{- t) log sec i (t — t) log tan d cos A log tan <f f 9 I 1» 49* 32*.04- 0.1 1 24 39.0+ 0.1 1 49 32.1 1 24 39.1 0 48 32.8 0 6 13.3 0.0098171 0.0001600 0.2284455 0.2384226 59° 59 31.61— 0 .35 59 59 31 .26. 30 .25 Giving the value found from the middle thread but one-half theweight of either of the other two, the mean is ^ = 59° 59 30.55. 187. To find the latitude from stars observed at only one of theirtransits over the prime vertical.—Notwithstanding the simplicity ofthe preceding methods, it is not always possible to apply themin the field. If the observer has but a short time to remain ata station, he may fail to find a suflicient number of bright starswhich pass near his zenith, and, if he uses those which pass atgreater zenith distances, much time is lost in waiting. But ifhe can use stars observed at only one of their transits, he may intwo or three hours obtain sufficient data for a very accuratedetermination o

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