OAA computing section circular NK 516 Periodic Comet Harrington-Abell 1969 III = 1976 VIII
= 1983 XVII The following improved orbital elements, by S. Nakano, are from 23 observations 1968 to 1984. Perturbations by all nine planets were taken into account. The comet has approached Jupiter to within 0.04 AU in 1974 April. The mean residual is +/- 1.17 arc seconds: Epoch = 1983 Dec. 12.0 ET T = 1983 Dec. 1.66920 +/- 0.00017 (m.e.) ET Peri. = 138.57699 +/- 0.00007 Node = 336.72135 +/- 0.00008 (1950.0) Inc. = 10.15485 +/- 0.00007 q = 1.7850634 +/- 0.0000007 AU e = 0.5388400 +/- 0.0000002 a = 3.8708110 +/- 0.0000003 AU n_ = 0.12941992 +/- 0.00000002 P = 7.616 +/- 0.0000010 years T = 1969 May 10.82048 ET Epoch = 1969 May 19.0 ET Peri. = 338.08206 e = 0.5240491 Node = 145.89217 (1950.0) a = 3.7260684 AU Inc. = 16.83812 n_= 0.13703384 q = 1.7734258 AU P = 7.192 years T = 1976 Apr. 21.81833 ET Epoch = 1976 Apr. 12.0 ET Peri. = 138.45566 e = 0.5400968 Node = 336.78090 (1950.0) a = 3.8616020 AU Inc. = 10.16448 n_= 0.12988315 q = 1.7759630 AU P = 7.588 years The predicted orbit for the 1991 return is as follows: T = 1991 July 6.92766 ET Epoch = 1991 July 3.0 ET Peri. = 138.67541 e = 0.5404394 Node = 336.63545 (1950.0) a = 3.8610557 AU Inc. = 10.17657 n_= 0.12991071 q = 1.7743892 AU P = 7.587 years The following residuals in seconds of arc are from the above orbital elements: Date/ UT R.A. (1950) Decl. *** O-C *** Code/Obs. h m s ! , " " " 1968 11 23.33199 03 23 51.52 -10 33 04.0 0.3+ 0.1+ 693/CT 1968 11 23.37713 03 23 49.24 -10 33 10.6 1.6+ 0.8+ 693/CT 1969 02 16.09817 03 37 17.72 +02 17 40.5 ( 3.1+ 0.4+) 693/CT 1969 02 16.12248 03 37 19.64 +02 18 02.1 2.5+ 0.2+ 693/CT 1969 04 19.13888 05 41 23.40 +15 43 05.1 0.2- 1.5- 693/CT 1969 04 20.14240 05 43 54.56 +15 52 10.3 1.1+ 0.7+ 693/CT 1975 10 06.39850 02 49.29 +30 09.9 ( 3.1+ 0.5-) 691/ST Y 1975 10 06.44624 02 49.26 +30 10.2 ( 4.0- 2.5+) 691/ST Y 1975 10 07.29588 02 48 54.82 +30 14 34.2 1.4- 0.3- 801/HO 1975 11 01.32882 02 29 59.23 +31 28 50.2 0.4+ 0.6+ 691/ST - continued - P/Harrington-Abell NK 516 - 2 Date/ UT R.A. (1950) Decl. *** O-C *** Code/Obs. h m s ! , " " " 1975 11 01.37245 02 29 56.28 +31 28 50.8 2.0- 0.5+ 691/ST 1975 12 04.07687 01 59 52.53 +29 56 05.8 0.3+ 0.5+ 801/HO 1975 12 05.14954 01 59.29 +29 51.0 ( 0.8- 3.8+) 691/ST Y 1975 12 05.17946 01 59.27 +29 50.8 ( 3.1- 0.4+) 691/ST Y 1976 01 02.02069 01 59 50.13 +28 00 05.7 0.3+ 0.0 801/HO 1976 01 26.23806 02 24 25.96 +27 44 23.9 2.6+ 0.6- 691/ST 1976 01 26.28223 02 24 29.66 +27 44 26.0 2.2+ 0.4- 691/ST 1976 02 24.03808 03 16 43.13 +28 43 47.5 2.5- 0.7- 801/HO 1976 02 25.17697 03 19 12.28 +28 46 46.2 0.2+ 0.4- 691/ST 1983 09 17.46600 07 22 37.58 +31 17 07.2 0.1- 0.3+ 675/PL 1983 09 18.47015 07 25 21.32 +31 13 08.4 1.3+ 0.8- 675/PL 1983 12 03.48993 10 20 51.74 +19 51 02.8 1.7- 0.2+ 707/ev 1984 01 08.39063 10 58 41.53 +13 42 07.7 ( 0.5+ 2.2-) 707/ev 1984 02 01.67674 10 56 41.25 +10 43 57.0 ( 0.9- 2.3-) 323/PR 1984 02 06.72014 10 53 33.46 +10 14 52.5 0.0 0.9- 323/PR 1984 02 08.32093 10 52 24.71 +10 05 56.2 0.3+ 0.3- 801/HO 1984 02 27.67500 10 35 34.77 +08 33 21.8 1.0- 0.1+ 323/PR 1984 03 01.25114 10 33 16.70 +08 22 03.4 0.9- 0.3- 801/HO 1984 03 26.62257 10 17 54.74 +06 32 57.8 1.3- 0.9- 323/PR 1984 04 02.14225 10 16 55.26 +06 02 38.0 1.9+ 0.6- 801/HO ( ) -------- Rejected Obs.
Director, Computing Section Syuichi Nakano 1987 August 20