Comet Update H1 K1 Period used
2P 170314 10.2 9.6 1937 - 2017
4P 170914 8.5 8.0 1932 - 2015
6P 211103 9.5 [30] 2021 Linear
8P 220103 7.5 8.1 2021
9P 231214 7.2 20.7 1972 - 2022
10P 180401 6.8 16.6 1967 - 2016 Linear
11P 210105 13.3U [20]
12P 241003 5.2 8.9 Poor fit due to outbursts
13P 241003 2.6 21.9 Currently a mag brighter than mean curve and better fitted by linear
15P 170914 8.1 14.3 1960 - 2015 Linear
16P 170914 6.3 23.5 1932 - 2015
19P 231214 8.0 13.9 1981 - 2022
21P 190204 9.4U 14.6
22P 180401 6.0 14.5 1945 - 2015
24P 180301 7.9U 21.9
26P 10208 11.9 12.1 1947 - 2013
32P 170914 7.9 11.3 1969 - 2015
33P 241203 14.5 [10]
37P 241203 6.4 31.7 Linear gives a better fit
38P 190303 9.4U [5]
40P 170914 5.2 27.2 1992 - 2015
41P 170703 10.9U 26.0
43P 181204 6.7 16.5 1951 - 2017
44P 180401 10.1 7.6 1947 - 2015
45P 181204 11.3 13.6 1954 - 2017
46P 201003 8.6 16.0 1986 - 2018
47P 120229 5.3 [15]
48P 181031 8.5U [10]
51P 120229 10.4 [10]
52P 6.8 [15]
53P 160831 5.9U 15.2
55P 8.5 26.7
56P 161115 9.1U [10]
58P 200902 6.3U [15]
59P 201003 11.0 [10] Secular fade
60P 201003 11.3 7.3 2012 - 2018 Linear
62P 240404 7.9 22.0
63P 130801 8.1U [10]
64P Linear
65P 170801 7.8U 9.3
66P 180901 7.9U 24.3
67P 180401 9.8 4.8 1982 - 2016 Linear
68P 200930 6.8 18.8 1976 - 2019
69P 8.1 7.5
70P 170914 11.5 7.5 1985 - 2015 Linear
71P 230502 2.2 35.9
73P 221102 10.9U 18.2 Linear
74P 201003 6.8 10.0 1992 - 2018
76P 200930 11.4 [21] 1975 - 2019 Secular fade
77P 181204 5.7 17.1 1986 - 2016
78P 200930 4.6 17.1 1997 - 2020 Linear
81P 181204 6.6 12.3 1978 - 2017
82P 120229 10.4 [10]
84P 170208 7.3 18.5 1985 - 2014
88P 180401 5.4 18.3 1987 - 2015 Linear
93P 071118 8.7 18.5
94P 181204 9.6 13.1 1984 - 2017
96P 161224 15.2 11.8 1986 - 2012
102P 131128 11.9U [10]
103P Linear
104P 181204 9.6 9.9 1991 - 2017
106P 000118 12.7U [5]
108P 170914 7.9 16.3 1985 - 2015
110P 120229 6.9 [10]
110P 170914 6.2 15.1 1988 - 2015
114P 000411 8.9U 28.9
116P 181204 5.6 13.4 1990 - 2016
117P 220801 3.3U 18.2
118P 181204 7.1 14.1 1996 - 2017
123P 190603 6.8 16.5
124P 170914 14.1 6.5 1991 - 2014
128P 6.3 [15]
132P 10.3 [15]
141P 180401 11.9 22.3 1994 - 2015
144P 240404 2.0 62.1 Linear
154P 170208 6.7 14.7 1992 - 2014
161P 050731 9.0 [10]
162P 210105 14.1 [10]
168P 130115 10.3U 6.7
177P 070102 9.1 16.8
185P 230731 12.0 [10]
193P 120229 11.4 [10]
201P 120229 12.7 [10]
204P 120229 9.9 [10]
210P 090328 12.9U 5.3
216P 120229 12.4 [10]
217P 171130 9.9U 10.7
218P 150517 13.9U [10]
222P 090928 16.4U [15]
226P 240102 11.9 [10]
237P 230830 5.2 23.5
240P 180301 5.4U 16.0
246P 210703 5.4U 15.0
260P 191231 11.3U [10]
262P 130115 9.4U [15]
263P 230403 17.9 [10]
290P 140306 1.0U 29.8
315P 170404 8.6U [10]
318P 151102 4.6U [20]
332P 160301 12.4U [15]
333P 241203 10.8 38.1
364P 230601 15.6 17.4
398P 210203 11.7U [20]
479P 240703 10.7 25.1
3200 180109 16.3U [5]
1995 O1 000411 -0.64 7.53
1997 BA6 001003 4.6U 9.8
1997 D1 8.0 [7.5]
1997 J2 5.1 5.8
1997 T1 6.6 16.4
1998 H1 11.0 5.0
1998 J1 6.2 6.3
1998 M5 000411 6.0U 10.2
1998 P1 991006 6.7U 9.9
1998 T1 990830 10.2U 4.5
1998 U5 9905xx 7.8U 19.6
1998 W1 11.7 [10]
1999 H1 000411 6.7U 11.5
1999 H3 000630 4.1U 12.5
1999 J2 011007 -1.2U 13.4
1999 J3 000411 9.0U 11.8
1999 K5 001127 6.7U 8.2
1999 K8 001127 -2.8U 20.8
1999 L3 000411 2.7U 29.9
1999 N2 000401 8.6U 7.7
1999 S3 000401 0.7U 39.8
1999 S4 000816 8.6 4.4
1999 T1 011007 6.3U 9.4
1999 T2 011007 6.5U 8.2
1999 U4 020414 6.9U 4.6
1999 Y1 011219 8.1U 4.3
2000 SV74 020414 8.0U 3.9
2000 W1 010312 10.8U 12.7
2000 WM1 020601 7.1U 10.6
2001 A2 011007 7.3U 10.6
2001 HT50 040619 6.5 [5]
2001 K5 020619 5.1 5.0
2001 MD7 020414 11.3U [10]
2001 OG108 020414 10.2U 5.9
2001 Q2 011202 10.7U 15.5
2001 Q4 050208 5.7U 6.6
2001 Q6 020414 5.5U 41.0
2001 RX14 030519 7.9U 7.8
2002 C1 020601 6.6U 8.5
2002 E2 020414 8.0U [10]
2002 F1 020601 10.6U 18.1
2002 G3 020414 20.7U 22.1
2002 O7 040619 8.9 4.2
2002 T7 041213 5.5U 6.3
2002 V1 030407 7.2 9.5
2002 X5 030407 7.2 6.7
2002 Y1 040619 6.5 9.5
2003 H1 040619 4.8 [15]
2003 K4 050420 4.0U 11.1
2003 T3 040919 6.6U 6.9
2003 T4 050420 7.8U 6.6
2004 F4 040703 8.0 8.1
2004 H6 040718 7.4 13.2
2004 Q1 050312 1.5U 27.5
2004 Q2 050901 5.2U 9.3
2004 R2 040928 10.1U 8.2
2005 A1 050731 8.5U 10.2
2005 E2 060410 6.8U 8.5
2005 L3 090818 5.9U [5]
2005 N1 050731 8.5U 22.9
2006 A1 070102 7.7 8.3
2006 L1 070125 6.7U 15.8
2006 L2 070102 5.1 14.8
2006 M4 070102 5.8U 9.1
2006 OF2 090607 6.7U 6.3
2006 P1 071201 4.4 9.7
2006 Q1 090328 4.8U 10.5
2006 S3 140401 0.2U 12.1
2006 VZ13 071201 8.2 11.1
2006 W3 101218 -0.7U 14.6
2007 E1 071201 6.9 25.9
2007 E2 071201 9.1 7.6
2007 G1 080901 0.3U [20]
2007 H1 071201 9.0 [10]
2007 N3 090607 5.5U 10.5
2007 Q3 091205 2.0U 13.2
2007 T1 080320 7.4 13.4
2007 W1 081022 8.6U 9.6
2008 A1 090328 5.9U 8.7
2008 C1 080508 6.9U 21.3
2008 Q3 090928 -1.1U 32.5
2008 J1 081124 5.1U 17.6
2008 T2 091205 6.5U 11.9
2009 F4 131114 5.7U 5.2
2009 F6 090928 6.8U [12]
2009 G1 090818 7.6U 9.3
2009 K5 101103 6.5U 6.3
2009 L2 090818 14.5U [5]
2009 P1 130115 4.4U 6.8
2009 R1 100818 6.7 7.6
2009 Y1 101218 3.3U 18.5
2010 G2 120719 7.8U 5.0
2010 S1 141001 -9.1U 22.7
2010 X1 110722 8.1 9.6
2011 A3 111223 -3.9U 28.6
2011 C1 111223 9.4U 4.3
2011 F1 131001 6.0U 6.9
2011 J2 131219 5.1U 9.5
2011 KP36 170202 -4.1U 19.5
2011 L4 130801 5.4U 9.5
2011 M1 111223 9.5U 17.2
2011 R1 130630 5.9U 10.5
2011 UF305 130115 -2.6U 34.2
2011 W3 130115 11.4U 17.5
2012 A2 131024 2.1U 12.4
2012 B1 130630 6.7U [10]
2012 F3 150818 5.0U 10.5
2012 F6 131016 5.3U 9.0
2012 J1 130115 3.2U [15]
2012 K1 150831 6.2U 6.9
2012 K5 130115 10.1U 6.0
2012 L2 130430 7.3U 9.8
2012 S1 131219 7.3 6.3
2012 T5 130115 10.0 15.3
2012 V2 131219 5.3U 10.2
2012 V4 130115 9.5U [15]
2012 X1 141216 5.0U 9.0 Post March 1
2013 A1 150104 8.7U 4.8
2013 CU129 131001 15.2U [10]
2013 E2 130801 6.9U 15.0
2013 J2 131024 10.1U [10]
2013 N4 131016 7.4U [10]
2013 R1 140629 6.5U 10.9 Post perihelion
2013 UQ4 140802 11.7U [10]
2013 US10 160602 5.6U 7.4
2013 V1 140116 9.7U 9.6
2013 V3 140306 8.0U 13.4
2013 V5 150104 8.8U 5.8
2013 X1 160803 4.7U 11.0
2014 E2 150104 7.0U 10.3
2014 L2 141116 9.1U [10]
2014 Q1 150831 7.6U 9.0
2014 Q2 160301 4.2U 6.4 Post perihelion
2014 Q3 150117 6.9U [20]
2014 R1 150104 8.4U [10]
2014 S2 160803 6.9U 3.4
2014 W2 160831 4.8U 12.2
2014 W11 150416 7.2U [10]
2015 C2 150517 8.9U [10]
2015 ER61 171130 7.2U 11.1 Post perihelion
2015 F3 150517 9.9U 13.5
2015 F4 151016 5.6U 25.9
2015 F5 150517 11.4U [10]
2015 G2 150802 8.2U 7.1
2015 O1 181201 4.5U 9.8
2015 P3 150831 11.8U [10]
2015 V2 171019 7.1U 5.6
2015 VL62 171019 8.8U 7.1
2015 WZ 160702 5.6U 32.9
2016 A8 161002 7.8U 16.5
2016 M1 181031 4.3U 10.6
2016 N4 171102 9.4U [5]
2016 N6 190204 4.6U 11.7
2016 R2 190603 7.8U 3.6 Variable
2016 U1 170202 11.9U 10.9
2016 VZ18 170404 12.6U [10]
2017 E1 170511 10.0U [30]
2017 E4 170511 10.3U [10]
2017 K2 231202 5.7 5.1
2017 M4 190603 4.2U 12.4
2017 O1 180301 8.1U 8.6
2017 S3 181201 8.7U 6.3
2017 T1 180301 12.3U 7.8
2017 T2 201002 6.2U 6.9
2017 T3 180801 8.8 11.3
2018 EF9 180601 8.6U [10]
2018 F4 201002 8.9U 3.4
2018 L2 190204 1.7U 25.8
2018 N1 181031 9.9U [10]
2018 N2 201002 6.6U 6.2
2018 R3 190731 5.7U 21.7
2018 V1 190102 11.4U [10]
2018 W1 190603 8.0U [15]
2018 W2 191201 8.3U 11.9
2018 Y1 190402 7.8U 10.9
2019 D1 190603 10.7U [10]
2019 L3 230731 -0.9 13.1 currently brighter than mean curve
2019 N1 210304 7.0U 10.1
2019 T4 230103 1.3 12.6
2019 U5 230703 4.1 10.6
2019 U6 201002 7.5U 17.2
2020 A2 200401 11.2U 10.4
2020 F3 201002 6.7U 11.6
2020 J1 220304 7.8U 5.5
2020 K1 230830 6.2 7.9
2020 K8 200902 12.9U [10]
2020 M3 210202 9.4U 9.4
2020 N1 210202 14.7U [5]
2020 P1 201101 14.2U 17.2
2020 Q1 201002 10.1U 6.5
2020 R4 210502 8.7U 18.4
2020 R7 220801 8.0U 7.6
2020 S3 210105 9.1U 10.5
2020 T2 211103 0.7U 27.3
2020 V2 230830 4.7 9.0
2021 A1 220204 8.1U 11.7
2021 A2 210304 9.2U [20]
2021 A4 210304 14.7U [10]
2021 D1 210501 8.9U 16.1
2021 E3 220703 6.2U 13.2
2021 F1 220703 7.6U 26.6
2021 G2 240404 5.0 7.8
2021 O3 220601 13.9U 3.3
2021 P4 220703 8.4U 12.2
2021 Q5 211002 11.1U [10]
2021 S3 240501 8.5 5.0
2021 T4 230830 8.9 8.0
2021 X1 230203 9.7 [5]
2021 Y1 230502 8.8 10.1
2022 A2 231101 4.5 15.2
2022 E2 241003 4.9 9.7
2022 E3 230703 6.8 9.4
2022 JK5 231101 7.7 [10]
2022 L2 240501 10.7 4.9
2022 N2 241203 6.1 9.6
2022 P1 230103 -0.4 45.1
2022 R2 221102 14.2U [10]
2022 U2 230203 9.8 [20]
2023 A3 241203 6.7 7.4
2023 C2 240905 11.1 2.1
2023 E1 231001 7.5 17.3 Discordant observations
2023 H2 240102 10.3 6.5
2023 P1 231001 9.0 8.1
2023 S2 231101 11.5 [10]
2023 S3 240302 12.6 27.0
2023 V4 240703 8.0 21.4
2024 B1 241102 10.8 [10]
2024 G3 241215 6.7 13.2
2024 S1 241003 12.4 [15]
The magnitude of the comet can be obtained from : m = H1 + 5 log d + K1 log r For periodic comets of multiple apparitions with stable behaviour, mean light curve parameters are given. For comets under observation up to 2022 November 30 a U after the H parameter indicates that the observed magnitudes have not been corrected for aperture. For comets currently under observation the Magnitude parameters are calculated for an aperture of 30cm, with no aperture correction applied to electronic observations. K1 values in brackets are assumed.
Comet Update H1 L1 dT 6P 220204 8.7U 0.0522 -85 Secular trend 7P 210903 12.3U 0.0320 -47.3 2021 8P 080421 6.8U 0.0429 -27.1 10P 180401 8.6 0.0231 -36.1 1967 - 2016 15P 170914 8.0 0.0478 -22.8 1960 - 2015 21P 201003 8.7 0.0283 -14.9 2018 37P 241203 11.5 0.0291 -35.2 2024 38P 190204 10.3U 0.0043 29.1 41P 120229 6.1 0.102 18 46P 021020 9.5U 0.0273 -31.7 Normal better 52P 10.9 0.0299 28.5 60P 201003 12.9 0.0115 -55.3 1999 - 2018 64P 201003 8.9 0.0325 -57.3 1981 - 2018 67P 180401 10.1 0.0157 -49.6 1982 - 2016 70P 170914 14.0 0.0042 -139 1985 - 2015 71P 171102 10.5U 0.0198 -41.2 73P 230103 10.3 0.0285 -73.1 78P 200930 9.4 0.0113 -27.6 1997 - 2020 88P 180401 7.6 0.0231 -22.0 1987 - 2015 96P 130115 9.7U 0.0501 -16 103P 111223 9.0U 0.0416 -26 104P 220304 10.1U 0.0640 -15 141P 000118 11.8U 0.0379 -21.2 144P 240404 9.8 0.0685 -22.9 156P 210304 10.1U 0.0472 -39.7 185P 130115 9.8 0.0375 -18 217P 120229 9.4 0.0180 -32 252P 181204 9.2 0.0895 -39.4 260P 130115 13.2 0.0145 -17 273P 130219 6.2 0.0753 -15 1998 K5 16.5 0.0201 -55.7 1998 U3 9.8 0.0151 46.0 2007 F1 071201 6.3 0.0508 10.3 2007 Q3 100610 6.2 0.0156 -44 2009 E1 090704 7.0 0.0719 -11.6 2009 K5 101218 7.0U 0.0172 -32 2014 S2 160503 7.6U 0.0081 -43 2016 R2 181031 8.7U 0.0028 196 2017 O1 180201 8.8U 0.0233 60 2019 U6 200702 5.8U 0.0711 13.9 2019 Y1 200702 6.9U 0.0629 -18.7 2019 Y4 200603 7.4U 0.1125 57.7 2020 F8 200603 6.0U 0.0931 24.2 2020 M3 201202 10.0U 0.0269 -13.1 2023 E1 230830 10.1 0.0658 -12.0 The magnitude of the comet can be obtained from : m = H1 + 5 log d + L1 abs(t - T + dT) if L1 is +ve the comet brightens towards perihelion, if dT is +ve the comet is brightest before perihelion.
Where there are insufficient observations to fully determine the r coefficient a value for K is assumed and given in [ ].