. Tables of calculated hour-angles and altitude azimuth table 30N. to 30S. : ex-meridian tables 60N. to 60S. and calculated reductions ans azimuths of bright stars from 1 hour to 3 hours from Meridian / c by Blackburne . Westlands Ex-Meridian Table maybe used, which gives a very wide limit. xlii EXAMPLES IN THE USE OF THE TABLES BELOW POLE EX-MERIDIAN AND POSITION-LINE 1910.—On April ist, soon after sunset, at 6h. 42 m. , observed altitude of -;;- a Cygni (Deneb)8° 46 W. of meridian when a chronometer indicated mean time at Greenwich 7 h. 34 m. 13 s. Approximatelatitude 52° N. and lon
. Tables of calculated hour-angles and altitude azimuth table 30N. to 30S. : ex-meridian tables 60N. to 60S. and calculated reductions ans azimuths of bright stars from 1 hour to 3 hours from Meridian / c by Blackburne . Westlands Ex-Meridian Table maybe used, which gives a very wide limit. xlii EXAMPLES IN THE USE OF THE TABLES BELOW POLE EX-MERIDIAN AND POSITION-LINE 1910.—On April ist, soon after sunset, at 6h. 42 m. , observed altitude of -;;- a Cygni (Deneb)8° 46 W. of meridian when a chronometer indicated mean time at Greenwich 7 h. 34 m. 13 s. Approximatelatitude 52° N. and longitude 12° W. Required latitude of meridian and position-line from it. I-;;- a- Cygni to Northward. 12° W. H. M. 34 13-48 0 Sid. T. (Green, noon)Accl. 7h. 34 m. M. ©s Azimuth from table (P- 334) Position-line H. M. 35 51-6+ 1 14-6 Obsd. alt. of -j;-Cor. (40 ft.) T. Alt Redn. (p. 334) Mer. Lat. Cor. for 16 Lat. 8 46-0 N. -12-3 M. T. ©s 6 46 13+ 0 37 6 0 37 6-2 8 33-7 N. N. i3°3 N. 76-7E. — I 20-2 Sid. T. at Sp.^rs 7 23 1920 38 21 7 13-5 N. 45 2-9 N. or at Inferi Transit. 10 44 58 W. 52 16-4 N. + 0-4 N. or I 15 2 W. 52 i6-8 N. .. » « j-/ ^ ^ 73--. SI : ^^il JJ^S-0^i^id4yMr BaiHry .^_^as \ 38)?tOr UBS «• ? ;«». ^r^* M.^*-^<j^^^^ V^^ ^s* V The above example is given to draw special attention to the great value of the ex-meridian problemwhen near the meridian below the pole. The observation gives with a minimum amount of work (whenwithin the limits of these tables) the latitude on a certain meridian, and the position-line from this curvature of this position-line is seen at a glance from the Azimuth Table, which is given on the samepage as the Reduction Table. In this example the change of azimuth only amounts to 0-7 of a degree in4 m. of time, or 1° of longitude. The position-line at Loop Head would be N. 78° E. This position-line crossed by a bearing of Tearag
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