OAA computing section circular NK 472 Periodic Comet Howell 1981 X = 1981k
The following improved orbital elements, by S. Nakano, are from 41 observations 1981 Aug. 29 to 1982 Jan. 16. Perturbations by all nine planets were taken into account. The mean residual is +/- 1.19 arc seconds. Epoch = 1981 Apr. 26.0 ET T = 1981 May 4.35195 +/- 0.00427 (m.e.) ET Peri. = 214.60503 +/- 0.00820 Node = 75.35462 +/- 0.00803 (1950.0) Inc. = 5.56858 +/- 0.00098 q = 1.6153891 +/- 0.0002049 AU e = 0.5074948 +/- 0.0000521 a = 3.2799429 +/- 0.0002290 AU nß = 0.16592226 +/- 0.00000030 P = 5.940 +/- 0.0006220 years (+/- 0.23 day) The predicted orbit for the 1987 return is as follows: T = 1987 Apr. 14.75911 ET Epoch = 1987 May 5.0 ET Peri. = 214.75756 e = 0.5080791 Node = 75.30796 (1950.0) a = 3.2776612 AU Inc. = 5.56793 nß= 0.16609554 q = 1.6123500 AU P = 5.934 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 ¡ , " " " 1981 08 29.35347 00 37 37.69 -07 34 32.1 0.8- 0.6+ 675/PL 1981 08 31.43472 00 36 24.18 -07 44 51.5 0.1+ 0.5+ 675/PL 1981 09 01.66142 00 35 37.36 -07 50 47.6 1.6- 1.7+ 474/JN 1981 09 01.68330 00 35 36.37 -07 50 55.1 2.8- 0.8+ 474/JN 1981 09 02.45000 00 35 06.17 -07 54 56.6 0.5- 0.7+ 675/PL 1981 09 02.73097 00 34 54.56 -07 56 11.2 1.7- 0.3- 474/JN 1981 09 02.74104 00 34 54.21 -07 56 18.2 ( 0.6- 4.4-) 474/JN 1981 09 03.29306 00 34 32.21 -07 59 14.1 1.1+ 3.1- 688/LO 1981 09 03.33403 00 34 30.41 -07 59 26.0 1.3+ 2.6- 688/LO 1981 09 04.43403 00 33 43.46 -08 04 53.6 0.2+ 0.1+ 675/PL 1981 09 05.04730 00 33 16.75 -08 07 59.3 0.8- 0.3- 046/KL 1981 09 05.06166 00 33 16.20 -08 08 04.4 0.9+ 1.1- 046/KL 1981 09 05.23556 00 33 08.82 -08 08 54.2 2.9+ 0.6+ 801/HO 1981 09 06.53517 00 32 10.05 -08 15 09.6 1.0- 0.5+ 474/JN 1981 09 06.54832 00 32 09.57 -08 15 12.6 1.3+ 1.4+ 474/JN - continued - NK 472 - 2 Date/ UT R.A. (1950) Decl. *** O-C *** Code/Obs. h m s ¡ , " " " 1981 09 07.20690 00 31 39.18 -08 18 41.6 2.2+ 1.3- 801/HO 1981 09 09.28754 00 29 59.60 -08 28 45.5 0.8- 0.3+ 675/PL 1981 09 10.25698 00 29 11.89 -08 33 22.8 0.4+ 0.0 675/PL 1981 09 10.50560 00 28 58.79 -08 34 33.5 0.3+ 0.3- 675/PL 1981 09 20.28580 00 20 21.07 -09 15 40.5 0.7- 0.4+ 675/PL 1981 09 21.34865 00 19 22.95 -09 19 22.9 0.1+ 0.7+ 675/PL 1981 09 22.21424 00 18 36.16 -09 22 19.7 1.2+ 2.8- 688/LO 1981 09 23.54942 00 17 23.14 -09 26 19.1 1.1- 0.5+ 474/JN 1981 09 23.56157 00 17 22.45 -09 26 21.4 1.1- 0.4+ 474/JN 1981 09 26.30208 00 14 55.46 -09 34 15.8 ( 1.2+ 4.3-) 688/LO 1981 09 26.33681 00 14 53.41 -09 34 21.3 ( 0.4- 4.5-) 688/LO 1981 09 26.72188 00 14 33.01 -09 35 11.4 2.6+ 2.8+ 372/sk 1981 09 26.96944 00 14 20.01 -09 35 52.7 0.8- 0.5- 489/HF 1981 09 26.98125 00 14 19.41 -09 35 54.2 0.1- 0.3- 489/HF 1981 09 27.24740 00 14 05.46 -09 36 30.7 0.0 0.3+ 707/ev 1981 09 27.57500 00 13 48.37 -09 37 15.7 1.5+ 0.5+ 372/sk 1981 09 28.95278 00 12 36.28 -09 40 16.9 ( 4.1- 0.1-) 489/HF 1981 09 29.21800 00 12 22.75 -09 40 47.6 0.1- 0.4+ 801/HO 1981 09 29.68021 00 11 58.91 -09 41 40.3 1.4- 0.3+ 372/sk 1981 10 04.25935 00 08 14.92 -09 48 11.0 0.6+ 1.4- 707/ev 1981 10 08.28474 00 05 16.16 -09 50 11.8 0.5+ 0.4+ 675/PL 1981 10 09.39516 00 04 30.15 -09 50 09.8 0.8+ 0.2- 675/PL 1981 10 19.28335 23 59 00.68 -09 38 36.0 0.1- 0.2- 675/PL 1981 10 20.36634 23 58 33.34 -09 36 08.6 2.6- 0.2+ 675/PL 1981 11 02.07843 23 55 40.66 -08 51 44.8 1.1- 0.1- 801/HO 1981 11 17.14619 23 57 47.85 -07 27 57.0 0.6- 1.5+ 675/PL 1981 11 17.15279 23 57 48.03 -07 27 55.0 0.3+ 0.9+ 675/PL 1981 11 23.05678 00 00 04.67 -06 48 04.4 ( 2.7+ 4.4+) 801/HO 1981 12 21.00260 00 19 21.18 -03 05 03.2 1.2+ 1.7- 801/HO 1982 01 15.10836 00 44 48.97 +00 41 36.9 0.4- 0.4- 675/PL 1982 01 16.09516 00 45 55.38 +00 50 43.2 0.6+ 0.5- 675/PL ( ) -------- Rejected Obs.
Director, Computing Section Syuichi Nakano 1985 July 7