OAA computing section circular NK 618 2P/Encke
The following improved orbital elements, by S. Nakano, are from 151 observations 1982 to 1994, including planetary perturbations by Mercury to Pluto and five minor planets and non-gravitational effect of style II. The mean residual is +/- 1.13 arc seconds. Epoch = 1994 Feb. 17.0 TT T = 1994 Feb. 9.47785 +/- 0.00007 (m.e.) TT Peri. = 186.27033 +/- 0.00017 Node = 334.72946 +/- 0.00015 (2000.0) Inc. = 11.94050 +/- 0.00004 q = 0.3309149 +/- 0.0000008 AU e = 0.8502126 +/- 0.0000007 a = 2.2092303 +/- 0.0000001 AU n' = 0.30015294 +/- 0.00000002 P = 3.284 +/- 0.0000003 years A1 = -0.015 +/- 0.008 A2 = -0.00182 +/- 0.00000 T = 1984 Mar. 27.68488 TT Epoch = 1984 Apr. 10.0 TT Peri. = 185.98652 e = 0.8463316 Node = 334.88987 (2000.0) a = 2.2190942 AU Inc. = 11.93294 n'= 0.29815389 q = 0.3410046 AU P = 3.306 years T = 1987 July 17.40144 TT Epoch = 1987 July 24.0 TT Peri. = 186.25221 e = 0.8498925 Node = 334.74134 (2000.0) a = 2.2099645 AU Inc. = 11.93155 n'= 0.30000336 q = 0.3317321 AU P = 3.285 years T = 1990 Oct. 28.56810 TT Epoch = 1990 Nov. 5.0 TT Peri. = 186.23403 e = 0.8502209 Node = 334.75005 (2000.0) a = 2.2091745 AU Inc. = 11.94517 n'= 0.30016430 q = 0.3308883 AU P = 3.284 years The predicted orbit for the 1997 return (MPC 23483) is as follows: T = 1997 May 23.59506 TT Epoch = 1997 June 1.0 TT Peri. = 186.27131 e = 0.8500146 Node = 334.72236 (2000.0) a = 2.2095052 AU Inc. = 11.92974 n'= 0.30009692 q = 0.3313936 AU P = 3.284 years The following residuals in seconds of arc are from the above orbital elements: Date Code Residual(") Date Code Residual(") Date Code Residual(") 1982/ 880909 568 1.1+ 0.9+ 931019 360 0.3+ 0.2- 820730 675 0.0 0.3- 880909 568 1.8+ 1.5+ 931023 494 1.8+ 0.3+ 1984/ 880909 568 1.3+ 1.2+ 931023 494 0.1- 0.7- 840127 372 (5.2- 3.0+) 880909 568 2.2+ 1.9+ 931024 691 1.0- 0.0 840225 168 (6.0- 1.8+) 880909 568 2.7+ 1.7+ 931024 691 1.0- 0.1+ 840225 168 (7.4- 2.3+) 880909 568 (3.9+ 2.4+) 931024 691 1.5- 0.3+ 840229 168 (3.2- 3.2+) 880911 568 1.3- 1.7+ 931114 411 1.3+ 1.6- 840301 168 1.7- 0.9- 880911 568 0.5- 1.2+ 931114 411 0.7+ 0.0 840302 168 2.7- 0.7+ 880912 568 1.1- 2.4+ 931114 494 1.7- 0.5- 840304 168 (2.0- 3.9+) 880912 568 1.3- 2.6+ 931114 494 0.0 0.7- 840308 168 (4.4- 1.3+) 880912 568 (2.1- 3.6+) 931117 691 0.1- 0.1+ 840309 168 (5.1- 5.0-) 1989/ 931117 691 0.2- 0.1+ 840314 168 0.4+ 0.3+ 890601 568 1.3+ 0.3- 931117 691 0.3- 0.0 840412 323 1.2- 0.2+ 890601 568 0.4+ 0.6- 931118 557 0.4+ 0.4+ 840413 323 1.2+ 0.8+ 890602 568 0.7- 1.5+ 931118 557 0.4+ 0.3+ 840423 474 (0.8- 4.5-) 890602 568 0.5- 0.3+ 931118 557 0.1+ 0.2+ 840423 474 (0.3+ 5.6-) 890602 568 0.5- 0.9+ 931118 557 0.3+ 0.5+ 840426 323 0.3+ 1.5- 890801 568 0.4- 0.4+ 931123 786 2.7+ 0.4+ 840427 323 0.2+ 1.7- 890801 568 0.5- 0.3+ 931202 107 (3.3+ 2.4-) 840502 323 1.8+ 0.7+ 890801 568 0.2- 0.4+ 931202 107 1.5+ 0.1- 840503 323 1.4- 1.9- 890802 568 0.5+ 0.8+ 931204 107 1.9+ 1.0+ 840526 474 0.7- 2.3+ 890802 568 0.5+ 0.8+ 931204 107 1.8+ 0.3- 840530 474 (5.7- 0.1+) 891227 568 0.4- 0.2- 931206 107 1.6+ 0.5- 840530 474 2.2- 1.0+ 891227 568 0.8- 0.3- 931207 360 1.2+ 0.4- 840606 323 (1.5- 3.3-) 891227 568 1.2- 0.0 931207 360 1.3+ 0.4- 840725 474 0.6- 0.7- 891227 568 1.0- 0.2+ 931208 691 0.0 0.2- 840725 474 1.2- 0.6- 1990/ 931208 691 0.2+ 0.4- 1985/ 900830 996 2.3+ 1.6+ 931208 691 0.1- 0.1- 850726 691 0.4+ 0.3- 900830 996 (2.7+ 4.3+) 931208 360 0.2+ 0.4- 850726 691 0.5- 0.7- 900920 657 (5.1+ 3.0-) 931208 360 0.3+ 0.3- 850726 691 0.3- 1.1- 900920 372 (4.8+ 1.0-) 931211 107 1.3- 0.0 850728 675 0.0 0.3+ 900920 372 0.4+ 1.0- 931211 107 0.7+ 1.2+ 850728 675 0.2+ 0.2+ 900926 503 (5.1+ 1.6+) 931212 107 0.6+ 1.8+ 850729 675 0.6+ 0.4- 900930 372 (3.8+ 0.7-) 931216 107 1.7+ 0.2- 850729 675 0.4+ 0.5- 900930 372 1.8+ 2.0- 931216 107 2.3+ 0.2- 850815 691 0.2- 0.7- 901001 494 2.6+ 1.6- 931217 107 2.0+ 1.0+ 850815 691 1.8+ 0.6- 1993/ 931217 107 0.1+ 0.3- 850815 691 1.0+ 0.5- 930722 691 1.6- 0.8+ 931223 107 0.1- 1.0- 1986/ 930722 691 (3.2- 1.5+) 931227 107 2.0- 1.4+ 860831 691 0.5+ 1.2- 930722 691 1.9- 0.8+ 931227 107 2.1- 2.7+ 860831 691 0.1+ 0.2- 930725 691 1.8- 0.3+ 931228 107 2.7- 1.6- 860831 691 0.1- 0.2- 930725 691 2.0- 0.4+ 931228 107 (4.8- 1.6+) 860901 691 1.2- 1.0- 930725 691 1.8- 0.3+ 1994/ 860901 691 0.9- 0.1- 930824 360 0.7+ 1.0- 940102 410 2.8- 1.6+ 860902 691 0.3- 0.5- 930824 360 1.3+ 0.2- 940102 410 2.5+ 0.4- 860902 691 0.4- 0.5- 930825 360 0.5- 0.2- 940104 887 1.5+ 0.2- 860902 691 0.1+ 0.7- 930825 360 0.3- 1.0- 940104 887 1.4+ 0.4- 860925 691 0.3+ 1.2- 930825 360 0.8- 0.1- 940105 691 1.2+ 0.0 860925 691 0.3+ 0.7- 930914 385 1.1- 0.1+ 940105 691 0.7+ 0.0 860926 691 0.4- 0.4+ 930914 385 1.5+ 1.0- 940109 360 1.5+ 0.9+ 860926 691 1.0- 1.0+ 930914 376 2.0- 1.3- 940109 360 0.8+ 1.0+ 860926 691 1.3- 0.7+ 930914 376 0.2+ 1.7- 940109 605 (5.1- 2.8+) 1987/ 930920 540 0.1+ 0.6- 940109 605 (6.1- 1.1+) 870813 474 2.3- 0.1+ 930920 540 0.4- 0.5- 940109 605 (4.3- 3.9+) 870813 474 0.2+ 1.2- 930925 360 0.2- 0.4- 940112 107 (5.3- 3.1+) 870815 323 2.6+ 0.8+ 930925 360 0.3+ 0.4- 940113 107 (3.7- 2.8+) 870817 323 0.7- 0.3+ 930926 360 0.3- 0.6- 940115 540 1.8- 2.7+ 870818 323 2.7- 1.5- 930926 360 0.3- 0.6- 940115 540 1.5- 2.0+ 870819 474 (6.3+ 2.0-) 931009 360 0.2- 0.8- 940115 540 1.6- 1.9+ 870819 474 0.3+ 1.0+ 931009 360 0.1+ 0.7- 940115 540 0.8- 1.0+ 1988/ 931011 360 0.1- 0.8- 940115 540 1.1- 1.1+ 880517 568 2.8+ 0.3+ 931011 360 0.4- 0.9- 940115 540 1.7- 1.3+ 880518 568 0.9+ 1.4+ 931019 360 0.2+ 0.2- 940118 107 (5.3- 5.4+) ( ) -------- Rejected Obs.
Director, Computing Section Syuichi Nakano 1994 Apr. 29