+ View the NASA Portal + Near-Earth Object (NEO) Program Search JPL JPL Small-Body Database Browser Search: [ help ]   1P/Halley Classification: Halley-type Comet* [NEO]          SPK-ID: 1000036 [ Ephemeris | Orbit Diagram | Orbital Elements | Physical Parameters | Discovery Circumstances | Close-Approach Data ] [ show orbit diagram ] alternate orbits: [epoch=1994-02-17.0] J863/77 (default) [epoch=1910-05-09.0] SAO/1910 [epoch=1835-11-18.0] SAO/1835 [epoch=1759-03-21.0] SAO/1759 [epoch=1759-03-21.0] J103/0 [epoch=1682-08-31.0] SAO/1682 [epoch=1682-08-31.0] I353/0 [epoch=1607-10-24.0] SAO/1607 [epoch=1607-10-24.0] H593/0 [epoch=1531-08-14.0] SAO/1531 [epoch=1456-06-28.0] SAO/1456 [epoch=1378-11-05.0] SAO/1378 [epoch=1301-11-09.0] SAO/1301 [epoch=1222-10-15.0] SAO/1222 [epoch=1145-04-02.0] SAO/1145 [epoch=1066-03-08.0] SAO/1066 [epoch=989-08-19.0] SAO/989 [epoch=912-07-14.0] SAO/912 [epoch=837-03-10.0] SAO/837 [epoch=760-06-02.0] SAO/760 [epoch=684-09-29.0] SAO/684 [epoch=607-03-18.0] SAO/607 [epoch=530-10-08.0] SAO/530 [epoch=451-06-25.0] SAO/451 [epoch=374-03-01.0] SAO/374 [epoch=295-04-25.0] SAO/295 [epoch=218-04-29.0] SAO/218 [epoch=141-03-24.0] SAO/141 [epoch=66-02-06.0] SAO/66 [epoch=-11-10-08.0] SAO/-11 [epoch=-86-08-23.0] SAO/-86 [epoch=-163-11-15.0] SAO/-163 [epoch=-239-06-07.0] SAO/-239 Orbital Elements at Epoch 2449400.5 (1994-Feb-17.0) TDB Reference: JPL J863/77 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e 0.967142908462304 5.035e-09   a 17.8341442925537 3.8913e-08 AU q 0.585978111516909 8.8924e-08 AU i 162.262690579161 6.7791e-06 deg node 58.42008097656843 9.0539e-06 deg peri 111.3324851045177 1.1714e-05 deg M 38.3842644764388 1.4226e-07 deg tp 2446467.395317050925 (1986-Feb-05.89531705) 4.7896e-06 JED period 27509.1290731861 75.32 9.0034e-05 2.465e-07 d yr n .01308656479244564 4.2831e-11 deg/d Q 35.08231047359043 7.6546e-08 AU Additional Model Parameters  Parameter Value Uncertainty (1-sigma)  A1 [EST] 2.696463929511566E-10 3.084E-11 A2 [EST] 1.554613388970244E-10 3.205E-15 S0 [EST] 861.6729585598083 16.03   Orbit Determination Parameters    # obs. used (total)      7428      data-arc span      57852 days (158.39 yr)      first obs. used      1835-08-21      last obs. used      1994-01-11      planetary ephem.      DE405      SB-pert. ephem.      SB405-CPV-2      fit RMS      1.0147      data source      ORB      producer      M.S.W. Keesey      solution date      2001-Aug-02 13:51:39   Additional Information  Earth MOID = .0637815 AU   T_jup = -0.605  [ show covariance matrix ] [ Ephemeris | Orbit Diagram | Orbital Elements | Physical Parameters | Discovery Circumstances | Close-Approach Data ] Physical Parameter Table Parameter Symbol Value Units Sigma Reference Notes comet total magnitude M1 5.5 mag n/a ICQ 2005 Handbook   comet total magnitude slope K1 8.0   n/a ICQ 2005 Handbook   comet nuclear magnitude M2 13.6 mag n/a ICQ 2005 Handbook   comet nuclear magnitude slope K2 5.0   n/a ICQ 2005 Handbook   comet nuclear phase coefficient PC 0.03   n/a ICQ 2005 Handbook   diameter diameter 11.0 km n/a Lamy,P.L.;Toth,I.;Fernandez,Y.R.;Weaver,H.A. (2004) Comets II, pp. 223-264   extent extent 14.9x8.2 km n/a Keller et al. (1987) Astron. Astrophys. 187:807-823 measurements repeatable within 100 to 200 meters geometric albedo albedo 0.04   0.01 Earth, Moon, and Planets, v. 89, Issue 1, p. 117-134 (2002)   1P/Halley          Discovered 1758-Dec-25 by Palitzsch, Johann Georg First known observation: -239/05/00 Reference: comet.dis Last Updated: 2003-08-29 [ show close-approach data ] Alternate Designations  Perihelion  Year (est.)  New-Style  Desig Roman  Numeral  Year/  Letter   1986.1   1P/1982 U1   1986 III   1982i   1910.8   1P/1909 R1   1910 II   1909c   1835.5   1P/1835 P1   1835 III     1760.1   1P/1758 Y1   1759 I     1684.8   1P/1682 Q1   1682      1609.5   1P/1607 S1   1607      1534.2   1P/1531 P1   1531      1458.9   1P/1456 K1   1456      1383.5   1P/1378 S1   1378      1308.2   1P/1301 R1   1301      1232.9   1P/1222 R1   1222      1157.6   1P/1145 G1   1145      1082.3   1P/1066 G1   1066      1007.0   1P/ 989 N1    989      931.6   1P/ 912 J1    912      856.3   1P/ 837 F1    837      781.0   1P/ 760 K1    760      705.7   1P/ 684 R1    684      630.4   1P/ 607 H1    607      555.1   1P/ 530 Q1    530      479.7   1P/ 451 L1    451      404.4   1P/ 374 E1    374      329.1   1P/ 295 J1    295      253.8   1P/ 218 H1    218      178.5   1P/ 141 F1    141      103.2   1P/  66 B1     66      -47.5   1P/ -11 Q1    -11      -122.8   1P/ -86 Q1    -86      -198.1   1P/-163 U1   -163      -273.4   1P/-239 K1   -239     [ Ephemeris | Orbit Diagram | Orbital Elements | Physical Parameters | Discovery Circumstances | Close-Approach Data ] 2013-May-20 18:29 UT (server date/time)   Site Manager:   Donald K. Yeomans Webmaster:   Alan B. Chamberlin