AnnualReport-1881 — Page 112

Right Ascension, s the variation of p in 100 years, q the star's Annual Proper Motion in Right Ascension, n the number of years elapsed, and c the small correction from the Table at page 5 of the Introduction to the Catalogue.

10, and the formula becomes,

In this case, n =

2

Mean R.A., 1882, January 1 = A + 10 (p + q) + $ + c Similarly, I have computed the Mean North Polar Distances by the formula,

Mean N.P.D., 1882, January 1D + 10 (p' + g′) +

s

2

+ c'

where c' is the small correction from the Table at page 27 of the Introduction to the Catalogue.

Forty-eight stars, formed into 28 pairs, were used in the determination, each pair having been observed from one to five times. The average is two times for each pair, making 56 determinations, on eleven nights in January and February. Of these it has only been necessary to reject two as imperfect. The following Table exhibits, for each star, in Column I its name as taken from the Greenwich Nine-Year Catalogue for 1872; in Column II its number in that Catalogue; in Column III its number in the British Association Catalogue; in Column IV its Mean Right Ascension for 1882, January 1, computed as above; and in Column VI its computed Mean North Polar Distance for the same date. Columns V and VII show the number of observations at Greenwich, of Right Ascension and North Polar Distance respectively, in the Nine-Year period 1868 to 1876, which were combined to form the Mean Places given in the Catalogue for 1872, January 1.

TABLE I.

COMPUTED MEAN PLACES OF STARS FOR 1882, JANUARY 1.

Star's Name. Number in Greenwich Nine-Year Catalogue for 1872. Number in B.A.C. Mean R.A., 1882, January 1. No. of Obs. of R.A. Mean N.P.D., 1882, January 1. No. of Obs. of N.P.D. 53 Andromeda 154 503 1 33 37.187 50 16 47 10 1 Piazzi I. 142........ 157 510 1 34 36.340 '5 106 Piscium 160 518 1 35 17.410 101 47 58 43.94 85 6 36.40 5 41 111 Piscium 175 574 1 47 26.777 87 23 44.50 5 57 Andromeda ............ 10) 628 1 50 39.541 28 48 14 13.80 27 24 Arietis... 216 745 2 18 29.565 6 79 55 28:58 Bradley 341 221 20 25.017 79 68 1.05 15 15 Trianguli 230 786 28 27.272 40 Arietis 258 807 41 55.189 41 Arietis 261 872 43 2.383 45 Arietis 268 901 49 10.732 58 Arietis 297 999 8 7.192 63 Arietis 311 1045 3 15 57.815 64 Arietis 313 1052 3 17 20.433 Tauri 325 1087 3 24 21.640 17 38 Persci 340 1138 3 36 55.159 .62 Tauri.......... 398 1326 4 13 6.000 61 Tauri 403 1346 4 16 7.792 75 Tauri 418 1377 4 21 41.075 55 49 41.01 3 Bradley 019 422 1391 4 23 48.471 72 12 31.10 3 ·Piazzi ÏV, 111 427 1408 4 27 15.083 63 13 37.28 14 Aogol o co co co co co 72 8 50,83 8 69 23 38.09 14 69 40 50.94 8 3 65 41 42,30 11 77 28 7.72 15 9 58 5 12.40 14 62 55 58.43 3 72 44 7.85 74 73 54 19.55 3. 50.87 87 Tauri 429 1420 4 20. 8.995 106 .89 Tauri 433 1432 4 31 24.271 61 17 13.94 73 92 Tauri 439 1437 4 32 31.60G 43 45.22 74 Piazzi IV. 148 440 1444 4 33 50.856 74 12 16.47 74 19 1.76 .61 36 54,37 99 11 Auriga.. 182 1602 5 5 21.264 *24 Orionis 507 1687 5 18 48.100 119 Tauri 51 39 24.90 83 125 Tauri 619 1726 595 17.702 4531.32 71 17 534 1778 5 32 25.422 29 42,01 64 10 13.96 132 Tanri 551 1837 5 41 46.444 65 28 24.69 54 Orionis 562 1876 5 47 23.721 58 Orionis 566 1883 5 48 46.976 37 Auriga 571 1900 5 51 40 402 69 44 59.25 82 67 Orionis 587 1958 0 50.079. 52 47 59,85 13 7.22 69 70 Orionis 594 1990 5 14.020 75 45 58.55 44 Aurige.. 601 2001 6 7 51.478 60 27 36 25 3 48 Auriga.. 620 2082 20 58.930 59 26 8.75 4 49 Auriga 635 2133 6 27 46.158 61 53 13.65 4 24 Geminorum 645 2163 6 30 53.625 73 30 4.99 31 31 54 Geminorum 706 2393 7 11 18.701 73' 14 53.45 60 Geminorum 724 2442 7 18 23.804 61 58 7.68 22 Geminorum 783 2469 7 22 24.322 3 61 50 31.02 4 68 Geminorum 737 2486 7 26 52.352 5 73. 55 15.25 9 78 Geminorum 700 2555 7 38 .5.616 115 01 41 24.62 107 83 Geminorum 774 2617 7 46 16:463 7 62 55 48 64 9 3 Cancri...................... 782 2659 7 54 1.538 72 22 10.12 5 9 Cancri.... 790 2700 7 30 18.628 1 67. 1 43.54. 4 10 Caneri.. 792. 2714 8 0 49.111 68 4 36.36 11