Angle from the North towards the East to Last Point of Contact. Longitude West from Greenwich. Latitude. 70° 71° 720 73° 74° | 750 760 770 78° | 79° 800 810 820 83° | 84° 39 40 41 42 43 44 45 46 47 48 49 50 Elements of the Eclipse, by which it may be computed for any Place, with the greatest accuracy. % 57 28 15 57 45 50 53 2 0 5 10 15 20 25 30 35 1.219200 1.488793 .421081 .414176 .407263 .400358 .393114 .36529 .379611 .372691 .365768 .355542 .331914 .311983 .335050 .331115 .324177 .317237 .310295 .303351 .296404 .299154 -282502 .275517 .263591 .261632 .251671 .247707 .240741 .233773 .226-03 .219530 .212 55 .205377 .199897 .191915 .184931 .177914 .170955 .163964 .156970 149974 .142976 .135975 .128972 .121969 .114961 .107952 .100910 .0939 26 086909 .079-91 .072870 .065917 .058522 .051794 .044761 .037732 .030697 9.976 9.974 9.520 9.508 2166 6-17 7599 2129 6500 1457 7619 1961 6326 1477 7639 1793 6153 1497 7660 1624 5979 1519 7681 1456 5905 1538 7702 1237 5632 1558 7723 1118 5158 1578 7711 0919 5234 1598 7761 0780 5110 1618 7705 0611 4936 1633 7806 | 0141 4762 1659 7826 0272 4587 1678 7047 *103 4113 1698 7869 9934 4239 1719 7889 | 9765 4061 1739 7910 9596 3989 1759 7931 9126 3715 1780 7953 9257 35 10 1800 7974 9088 3365 1920 7995 8919 3191 1841 8015 8750 3017 1861 8036 8591 2513 1882 8057 8111 2669 1902 8078 8212 2495 1923 8099 8073 2321 1913 8120 7903 2146 1961 8111 7733 1972 1941 8152 7561 1797 2001 8163 7394 1622 2025 8204 7221 1418 2015 8225 7055 1273 2065 9216 67-6 1039 2095 8266 6717 0922 2105 8297 65518 0717 2125 835 6378 0572 5360 9523 9319 5019 9174 0 2 12 3.3 3 27 3.7 4 42 4.1 5 57 4.6 7 12 5.0 827 5.5 9 42 5.9 10 57 6.4 12 12 6.8 13 27 7.3 14 42 78 8.2 17 12 8.7 18 27 9.2 19 42 9.6 20 57 10.1 22 12 10.6 23 27 11.0 24 42 11.5 25 57 12.0 27 12 12.4 28 27 12.9 29 42 13.4 30 57 13.8 32 12 14.3 33 27 14.8 34 42 15.2 35 57 15.7 37 12 16.2 38 27 16.6 39 42 17.1 40 57 17.6 42 12 18.0 43 27 18.5 44 42 19.0 45 57 19.4 47 12 19.9 48 27 20.3 49 42 20.8 50 57 21.2 52 12 21.7 53 27 22.2 54 42 22.6 55 57 23.1 57 12 23.6 58 27 24.0 59 42 21.5 60 57 24.9 62 12 25.4 63 27 23.8 64 42 26.3 65 57 56.7 67 12 27.2 69 27 37.6 69 42 28.1 70 57 28.5 7424 45 1 30 These tables are adapted to computation by the following modification of Bessel's formulæ, which was suggested by T. Henry Safford, Jr. d=the latitude of the place. a=its eastern longitude from Greenwich. log. e=8.9110835 log. (1-e?)=9.9971066 sin.y=esin. 0 h=sec, w cos. O k=(1-e?) sec. y sin. O m=V (bc) If the instant for computation were correctly chosen at the time of begin. ning or end of the eclipse, m would be exactly equal to a. If m is not equal to a, the instant for a new computation, and which will be an approximation to the actual time of beginning, may be found by adding to the preceding time of computation an interval t, which may be obtained in seconds by the formulæ log. u'=1.86167 log. H'=1.3757 a'=A — M'h cos. (u +2) 1000000 (m-a) and if y is taken of the same sign with a, it is a sufficiently near approximation to the angle of contact from the north towards the east. The magnitude of the eclipse is found by taking the difference (with regard to the signs) of V at the beginning and end of the eclipse, and if this difference is denoted by 29, the magnitude of the eclipse is 24.5 sin. '} y or 24.5 cos. 254 accordingly as o is acute or obtuse. The value of y may also be obtained by the formulæ tan.x= p=4-X and the expression of t may be changed to t=1000000.m-a cos. x sin. a sin. sin. V с The elements of the sun for this table were derived from Bessel's tables, those of the moon from Damoiseau's tables corrected by Airy for Plana’s theory, and with the additional corrections given by Hansen's new terms and by Airy's comparison with the Greenwich Observations. The following is an example under these tables for the computation of the beginning of the eclipse for the Washington Observatory. A= lat. 38° 51' 391.25 sin. 6 9.7978800 B 1.462041 8.7089635 Ek .591 152 Hh cos. (uta) .080875 b .951764 с .394136 for Oh. 29m. 30s. Fk .589272 5° 49' 34".6 Gh cos. (u+a) .083057 .112079 b 9.9785292 sin. (uta) 9.9762786n 9.0495242 cos. (u+a) 9.5074402 9.5140267n h sin. (uta) 9.8679984n tan. 54 9.5354975n -1.064186 h sin.(uta) .737902 .326284 .326608 d'h cos. (uta) 18.28 1.2609 B= 23.06 5.53 V 322 71 b cos. y=-4.30 al - cos. y= 144.16 t=-28..2 21 13.2 с m 64 |