BAA Comet Section : Comets discovered in 2020

Updated 2020 September 22


  • 2002 T5 (P/LINEAR)
  • 2008 QP20 (P/LINEAR-Hill)
  • 2011 U2 (P/Bressi)
  • 2011 R3 (P/Novichonok-Gerke)
  • 2012 KA51 (Palomar)
  • 2014 OG392 (PanSTARRS)
  • 2017 PY24 (PanSTARRS)
  • A/2020 A1 (A/NEOWISE)
  • 2020 A2 (Iwamoto)
  • 2020 A3 (ATLAS)
  • A/2020 B1 (A/PanSTARRS)
  • 2020 B2 (Lemmon)
  • 2020 B3 (Rankin)
  • 2020 BS7 [A/Lemmon]
  • 2020 BZ12 [A/PanSTARRS]
  • 2020 BU13 [A/PanSTARRS]
  • 2020 EP [A/Lemmon]
  • 2020 F1 (396P/Leonard)
  • 2020 F2 (ATLAS)
  • 2020 F3 (NEOWISE)
  • 2020 F4 (394P/PanSTARRS)
  • 2020 F5 (MASTER)
  • 2020 F6 (PanSTARRS)
  • A/2020 F7 [/A/Lemmon]
  • 2020 F8 (SWAN)
  • 2020 G1 (P/Pimental)
  • 2020 H1 (395P/Catalina-NEAT)
  • 2020 H2 (Pruyne)
  • 2020 H3 (Wierzchos)
  • 2020 H4 (Leonard)
  • 2020 H5 (Robinson)
  • 2020 H6 (ATLAS)
  • 2020 H7 (Lemmon)
  • 2020 H8 (PanSTARRS)
  • A/2020 H9 [A/PanSTARRS]
  • 2020 HB11 [A/Lemmon]
  • 2020 J1 (SONEAR)
  • 2020 K1 (PanSTARRS)
  • 2020 K2 (PanSTARRS)
  • 2020 K3 (Leonard)
  • 2020 K4 (PanSTARRS)
  • 2020 K5 (PanSTARRS)
  • 2020 K6 (Rankin)
  • 2020 K7 (PanSTARRS)
  • 2020 K8 (Catalina-ATLAS)
  • 2020 K9 (P/Lemmon-PanSTARRS)
  • 2020 KU7 [A/PanSTARRS]
  • 2020 M1 (P/PanSTARRS)
  • 2020 M2 (P/Lemmon)
  • 2020 M3 (ATLAS)
  • A/2020 M4 [A/PanSTARRS]
  • 2020 M5 (ATLAS)
  • 2020 N1 (PanSTARRS)
  • 2020 N2 (ATLAS)
  • 2020 O1 (P/Lemmon-PanSTARRS)
  • 2020 O2 (Amaral)
  • 2020 O3 (P/PanSTARRS)
  • 2020 O4 (P/PanSTARRS)
  • 2020 OR5 [A/PanSTARRS]
  • 2020 OS5 [A/PanSTARRS]
  • 2020 OP7 [A/PanSTARRS]
  • 2020 P1 (NEOWISE)
  • 2020 P2 (P/Boattini)
  • 2020 P3 (ATLAS)
  • 2020 P4 (SOHO)
  • 2020 PV6 [A/PanSTARRS]
  • 2020 Q1 (Borisov)
  • 2020 Q2 (PanSTARRS)
  • 2020 QN6 [A/PanSTARRS]
  • 2020 QO6 [A/PanSTARRS]
  • 2020 R1 (P/PanSTARRS)
  • 2020 R2 (PanSTARRS)
  • 2020 R3 (P/McNaught)
  • 2020 R4 (ATLAS)
  • 2020 R5 (P/PanSTARRS)
  • 2020 R6 (Rankin)
  • 2020 S1 (P/PanSTARRS)
  • 2020 S2 (PanSTARRS)
  • 2020 S3 (Erasmus)

  • When observing a comet please try to forget how bright you think the comet should be, what it was when you last viewed it, what other observers think it is or what the ephemeris says it should be.

    The equations for the light curves of comets that are currently visible use only the raw observations and should give a reasonable prediction for the current brightness. If the comet has not yet been observed or has gone from view a correction for aperture is included, so that telescopic observers should expect the comet to be fainter than given by the equation. The correction is about 0.033 per centimetre. Values for the r parameter given in square brackets [ ] are assumed. The form of the light curve is either the standard m = H0 + 5 log d + K0 log r or the linear brightening m = H0 + 5 log d + L0 abs(t - T + D0) where T is the date of perihelion, t the present and D0 an offset, if L0 is +ve the comet brightens towards perihelion and if D0 is +ve the comet is brightest prior to perihelion.

    Observations of comets in 2020 are given in ICQ format. 

    Full details of recently discovered objects will not appear until they are available on the CBAT web pages. The actual accuracy of preliminary orbits is often (nearly always) much worse than the published accuracy implies.  In part this is because each orbital solution is treated as a mathematical construct and does not take account of observational error.  JPL does publish the errors, whereas the MPECs do not.


    2002 T5 (P/LINEAR)
    Erwin Schwab recovered the comet in images taken with the 0.8-m f/3 Schmidt reflector at Calar Alto, Spain. on August 18.11. The comet was some 5' from the expected position. [CBET 4835, 2020 August 19] It has not yet been given a designation for the return.
    2008 QP20 (P/LINEAR-Hill)
    Sam Deen found images of the comet in DECam data taken with the 4.0m reflector at Cerro Tololo on 2016 January 15.26 and 2016 March 1.14. These were identified by Seiichi Nakano as being a return of 2008 QP20. The comet was close to the expected position. [CBET 4832, 2020 August 17] It has not yet been given a designation for the return.
    2011 R3 (P/Novichonok-Gerke)
    Seiichi Nakano found images of the comet in PanSTARRS 1 data taken with the 1.8m Ritchey-Chretien on 2020 June 20.49 and July 18.36. The comet was close to the expected position. The comet was put into its present orbit during a series of encounters with Jupiter: 0.87 au in 1992 October, 0.11 au in 1993 August and 0.45 au in 2005 April. Prior to these encounters the comet was in a more distant orbit with perihelion at 5.2 au and a period of 19.4 years. [CBET 4833, 2020 August 17] It has not yet been given a designation for the return.
    2011 U2 (P/Bressi)
    Seiichi Nakano found images of the comet in PanSTARRS 1 data taken with the 1.8m Ritchey-Chretien on 2020 June 17.55 and on July 17 and 20. The comet was close to the expected position. The comet passed 0.97 au from Jupiter in 2020 February in an encounter that reduced the perihelion distance from 4.8 to 4.1 au and the period from 12.7 to 10.3 years. [CBET 4831, 2020 August 16] It has not yet been given a designation for the return.
    2012 KA51 [Palomar]
    An object of 19th magnitude was found in images taken with the Zwicky Transient Factory camera on the 1.2m Oschin Schmidt on 2012 May 22.16.  It was at perihelion at 4.9 au in 2011 November and is in a high inclination near parabolic orbit. JPL class it as a Trans-Neptunian Object. Sam Deen has found images showing a cometary nature and it will presumably be reclassified.
    2014 OG392 (PanSTARRS)
    PanSTARRS 1 discovered a 21st magnitude asteroid in images taken with the 1.8m Ritchey-Chretien on 2014 July 28.50. There were additional pre-discovery observations back to 2011 July. The object, originally classified as a Centaur, is at perihelion at 10.0 au in 2021 November and has a period of around 40 years. CBET 4731 [2020 March 16] reports that a coma was noted in six images taken with large telescopes between 2017 July and 2019 December. It seems a long time for cometary activity to go unreported.
    2017 PY24 [A/PanSTARRS]
    PanSTARRS 1 discovered an asteroid in images taken with the 1.8m Ritchey-Chretien on 2017 August 7.43. The object, classified by JPL as a Centaur, was at perihelion at 1.3 au in 2017 September and is in a high inclination orbit with a period of around 70 years. Sam Deen has found images showing a cometary nature and it will presumably be reclassified.
    A/2020 A1 (A/NEOWISE)
    An 20th magnitude object was discovered from the NEOWISE satellite on January 1.76. It was posted on the PCCP as N00g0p4. No cometary activity has been detected. [MPEC 2020-A119, 2020 January 12] The object was at perihelion at 1.7 au in 2019 December.  JPL classify it as a Centaur.
    2020 A2 (Iwamoto)
    Masayuki Iwamoto, Awa, Tokushima-ken, Japan, discovered a 13th magnitude comet on two CCD frames taken on January 8.86 with a 10-cm Pentax 400-mm-f.l. f/4.0 lens and a Canon EOS 6D camera. It was posted on the PCCP as IF033. Following posting, Gennady Borisov confirmed the 15th magnitude comet in frames taken on January 13.15. [CBET 4714, 4715, MPEC 2020-132, 2020 January 13/15] The comet was discovered at perihelion at 1.0 au.   Despite describing the orbit as very preliminary and with only five observations over a five day arc, Dan Green gives four decimal places for the angular elements on the CBET. A similar orbit, based on six observations is provided by Hirohisa Sato.  The orbit suggests that whilst it may brighten a little, it will not become brighter than 13th magnitude. Its elongation will increase, but it is a morning object. Some visual observations suggest that it may be as bright as 9th magnitude.
    2020 A3 (ATLAS)
    A 19th magnitude comet was discovered in images taken with the 0.5m Schmidt at Mauna Loa on January 7.60. by the ATLAS (Asteroid Terrestrial-impact Last Alert System) team. It had been posted on the PCCP as A10jo2S. [CBET 4716, MPEC 2020-B60, 2020 Janaury 21]. The comet was at perihelion at 5.8 au in 2019 June.
    A/2020 B1 [PanSTARRS]
    PanSTARRS 1 discovered an asteroid in images taken with the 1.8m Ritchey-Chretien on January 19.37. The object, classified by JPL as a Trans-Neptunian Object, was at perihelion at 1.7 au in 2019 December and has a long period orbit with aphelion at 100 au. It was placed on the PCCP as P10W9bB. No cometary activity has been detected.
    2020 B2 (Lemmon)
    The Mt Lemmon Survey discovered a comet of 21st magnitude in images taken with the 1.5m reflector on January 19.45. It was placed on the PCCP as C1T0QN2. Richard Miles was amongst those making confirming observations. [MPEC 2020-C110, 2020 February 6]. The comet was near perihelion at 2.8 au. It is in a long period orbit of around 500 years.
    2020 B3 (Rankin)
    David Rankin discovered a comet of 19th magnitude in images taken with the 1.5m reflector on January 29.44 during the Mt Lemmon Survey. It was placed on the PCCP as C20NF62. There were pre-discovery images from PanSTARRS on January 25. [MPEC 2020-C111, 2020 February 6]. The comet was at perihelion at 3.4 au in 2019 October. For some reason JPL currently classify it as a Jupiter-family comet.
    2020 BS7 [A/Lemmon]
    The Mt Lemmon Survey discovered an object of 20th magnitude in images taken with the 1.5m reflector on January 19.08. [MPEC 2020-B163, 2020 January 25]. It was placed on the PCCP as C1RWKU2. The object was at perihelion at 0.4 au in 2019 November and has a period of around 5.4 years. JPL classify it as an Apollo asteroid and an NEO.
    2020 BZ12 [A/PanSTARRS]
    PanSTARRS 1 discovered an asteroid in images taken with the 1.8m Ritchey-Chretien on January 19.62. The object, classified by JPL as an Apollo asteroid and an NEO with MOID of 0.08 au, is at perihelion at 0.6 au in 2020 April and has a retrograde orbit with a period of around 20 years. It was placed on the PCCP as P10W6lW. No cometary activity has been detected.
    2020 BU13 [A/PanSTARRS]
    PanSTARRS 1 discovered an asteroid in images taken with the 1.8m Ritchey-Chretien on January 25.30. The object, classified by JPL as an Apollo asteroid and an NEO with MOID of 0.06 au, was at perihelion at 0.1 au in 2019 December and has an orbit with a period of around 4 years. It was placed on the PCCP as P10WTyQ. No cometary activity has been detected.
    2020 EP [A/Lemmon]
    The Mt Lemmon Survey discovered an object of 21st magnitude in images taken with the 1.5m reflector on March 2.44. [MPEC 2020-F03, 2020 March 16]. It was placed on the PCCP as C2AJT22. The object was at perihelion at 2.5 au in 2020 February and has peiodic orbit of around 30 years. JPL classify it as a Centaur.
    2020 F1 (396P/Leonard)
    Gregory J Leonard discovered a comet of 20th magnitude in images taken with the Mt Lemmon Survey 1.5m reflector on March 16.33. It was placed on the PCCP as C2CU0U2. There were pre-discovery images from PanSTARRS in 2019 January, December and 2020 January and from Mt Lemmon in 2020 February. [CBET 4736, MPEC 2020-F144, 2020 March 26]. The comet was at perihelion at 4.0 au in 2019 August and has a period of 18 years.

    With a published orbit, several researchers looked for pre-discovery observations in archival data, coming up with observations made in 2002 March.  It was given a designation of 2002 F4 for this return. The linked orbit shows that the comet made a close pass of 0.0074 au to Saturn on 1936 May 7. Prior to that time the orbit had a perihelion distance of around 9.0 au and a period of 37 years - a typical Centaur. It has since made moderately close passages to both Jupiter and Saturn. [CBET 4737, 2020 March 27, MPEC 2020-K92, 2020 May 21]


    2020 F2 (ATLAS)
    A 19th magnitude object was discovered in images taken with the 0.5m Schmidt at Haleakala on March 21.62 by the ATLAS (Asteroid Terrestrial-impact Last Alert System) team. The next day it was detected by PanSTARRS, who noted a coma. It was posted on the PCCP as A10kZLv. Prediscovery images from PanSTARRS were found from 2019 May, August and 2020 February. [CBET 4739, MPEC 2020-G04, 2020 April 1]. The comet was at perihelion at 8.8 au in 2022 July.
    2020 F3 (NEOWISE)
    An approximately 17th magnitude comet was discovered from the NEOWISE satellite on March 27.71. It was posted on the PCCP as N00gbay. Several observers confirmed the cometary nature, including John Drummond who showed an image during the BAA webinar on 2019 Y4 on the evening of April 1. [CBET 4740, MPEC 2020-G05, 2020 April 1/2] The object was at perihelion at 0.3 au in 2020 July.  Michael Mattiazzo noted that the comet already appeared to be about 13th magnitude, which implied a significantly brighter absolute magnitude to that used in the CBET.  This would be in line with NEOWISE magnitudes often being fainter than the equivalent visual magnitude.  

    Marco Goiato was able to observe the comet on April 21 and 26 in his 0.22m reflector when it was rapidly brightening at 11th magnitude.  The final ground based observation before perihelion was by Michael Mattiazzo on June 10 when it was about 6.8 in his 15x70B.  It moved into the SOHO C3 field on June 22, when it was around 2nd magnitude and had brightened to around 0th magnitude when it left the field on June 27.  Nicolas Biver reported it as about 1st magnitude in 7x50B on July 3.  It was a fine sight in early July, showing a long tail and easily visible to the naked eye.  As the comet climbed higher in the sky images showed spiral dust shells in the coma emanating from an active region on the nucleus.   By late July it had faded to 5th magnitude and was still showing a short tail to visual observers.  It will fade fairly rapidly but should remain visible until late August.


    2020 F4 (394P/PanSTARRS)
    PanSTARRS 1 discovered a comet in images taken with the 1.8m Ritchey-Chretien on March 24.52. It was placed on the PCCP as P10YaJ8. Very quickly, Richard Weryk of PanSTARRS found pre-discovery images from 2009, 2011 (when it was given the designation 2011 GN5), 2018, 2019 and 2020. Additional NEAT images were then found from 2002. The object was effectively stellar in 2009 and 2011. [CBET 4742, MPEC 2020-G64 2020 April 6] The comet was at perihelion at 2.7 au in 2019 November and has a period of 9 years.
    2020 F5 (MASTER)
    The MASTER team reported the discovery of a 16th magnitude comet in ATEL 13619 on April 6. The comet was found using the MASTER (Mobile Astronomical System of the Telescope-Robots) auto detection system with the robotic 0.4m f/2.5 reflector at San Juan, Argentina on March 28.25, with images from earlier in March then found in data collected by the system at the SAAO, Sutherland, South Africa. It was confirmed by other observers and formally announced by the MPC and CBAT. [CBET 4745, 4746, MPEC 2020-G73, 2020 April 8]. The comet will reach perihelion at 4.3 au in 2021 March.  It might reach 14th magnitude, but will not be well placed for observation from the UK.
    2020 F6 (PanSTARRS)
    PanSTARRS 1 discovered an object in images taken with the 1.8m Ritchey-Chretien on March 21.61, with a coma being reported the next day. It was placed on the PCCP as P10XLLe. [CBET 4748, MPEC 2020-G74 2020 April 8] The comet was near perihelion at 3.5 au.
    A/2020 F7 [A/Lemmon]
    The Mt Lemmon Survey discovered an object of 20th magnitude in images taken with the 1.5m reflector on March 22.23. [MPEC 2020-G78, 2020 April 10]. It was placed on the PCCP as C2DHE12. The object will reach perihelion at 5.3 au in 2021 November and is in a very long period orbit with a high inclination. It has not so far shown any cometary activity. JPL classify it as a Trans-Neptunian Object.
    2020 F8 (SWAN)
    Michael Mattiazzo reported a possible comet of around 10th magnitude in SWAN images between April 1 and April 7 via the comets-ml on April 10. Preliminary orbits were quickly calculated by several amateurs, with a consensus that it was in a retrograde orbit with perihelion around 0.4 au towards the end of May. This would bring it into view for UK observers from mid May, when it might be a 4th magnitude object. The comet was placed on the PCCP as SWAN01 by the MPC, though the CBAT use the designation SWAN20B. CBET 4750 giving a preliminary orbit was issued on April 11. It is possible that the comet is in outburst, in which case its future brightness is uncertain. The MPC chose to designate the comet as 2020 F8 (rather than G1) because SWAN images showing the comet on March 25 were subsequently found. [MPEC 2020-G94, 2020 April 12].  It became another of the spring 2020 comets that failed to survive perihelion.
    2020 G1 (P/Pimental)
    Eduardo Pimental discovered a 15th magnitude comet in images taken by himself, Christovao Jacques and Joao Ribeiro de Barros on April 13.90 with the "Southern Observatory for Near Earth Research" (SONEAR) 0.28-m f/2.2 astrograph at Oliveira, Brazil. It was soon confirmed by many other observers. There was some uncertainty about the orbit, with the discovery MPEC (issued at 04:22) giving ellipital ellements with a period of 8.6 years based on observations from April 13 - 17 and including a description by Dan Green dated as June 16. The MPEC will presumably be re-published. The CBET (issued at 04:52) gives both parabolic and ellipitical elements, the latter with a period of around 11 years based on observations from April 13 - 16. [CBET 4754, MPEC 2020-H06, 2020 April 17] Further observations suggest an orbit with a period of 7 years, which would imply an approach to Jupiter in 2007, but this remains uncertain.  [CBET 4759, 2020 April 28].  Further, for some reason unpublished, observations now give a still uncertain orbit with a period of about 6.8 years and no Jupiter approach. [CBET 4773, 2020 May 13].  JPL, without access to these observations currently give an orbit with eccentricity of 0.86, perihelion at 0.5 au and a period of 7.0 years +/-0.1 years. This orbit gives a Jupiter MOID of 0.25 au and an Earth MOID of 0.27 au, though with no recent close approaches. 
    2020 H1 (395P/Catalina-NEAT)
    2005 JD108 (P/Catalina-NEAT) was recovered on 2020 April 26.08 by Erwin Schwab in images taken by Diana Abreu with the 1.0m reflector at the ESA Optical Ground Station, Tenerife. The recovery was confirmed by P Breitenstein with the Faulkes-North   [CBET 40nn, MPEC 2020 H-2020, 2020 April 28]  The comet has perihelion at 4.1 au in 2021 December and a period of 16.8 years.
    2020 H2 (Pruyne)
    Teddy (Theodore) Pruyne discovered a comet of 16th magnitude in Catalina Sky Survey images taken with the 0.68m Schmidt on April 26.47. It was placed on the PCCP as C166T11 and quickly confirmed by Michael Jaeger and other astrometrists. [CBET 4761, MPEC 2020-H220, 2020 April 28]. The comet was close to perihelion at 0.8 au.
    2020 H3 (Wierzchos)
    Kacper Wierzchos discovered a comet of 19th magnitude in images taken with the 1.5m reflector of the Mt Lemmon Survey on April 25.45. It was placed on the PCCP as C2MWPV2. [CBET 4762, MPEC 2020-H221, 2020 April 28]. The comet is at perihelion at 2.3 au in 2020 June.
    2020 H4 (Leonard)
    Gregory Leonard discovered a comet of 20th magnitude in images taken with the 1.5m reflector of the Mt Lemmon Survey on April 21.47. It was placed on the PCCP as C2KXCV2. [CBET 4766, MPEC 2020-J21, 2020 May 3]. The comet is at perihelion at 0.9 au in 2020 August. If the absolute magnitude is brighter than provisionally determined it might get within visual range at the time of perihelion.
    2020 H5 (Robinson)
    James Robinson discovered a 19th magnitude comet in images taken with the 0.5m Schmidt at Haleakala on April 22.33 by the ATLAS (Asteroid Terrestrial-impact Last Alert System) search programme. It was posted on the PCCP as A10lBfp. [CBET 4767, MPEC 2020-J22, 2020 May 3]. The comet is at perihelion at 9.4 au in 2020 October.
    2020 H6 (ATLAS)
    A 19th magnitude comet was discovered in images taken with the 0.5m Schmidt at Haleakala on April 22.34 by the ATLAS (Asteroid Terrestrial-impact Last Alert System) team. It was posted on the PCCP as A10lExP. [CBET 4768, MPEC 2020-J23, 2020 May 3]. The comet is at perihelion at 4.7 au in 2021 October.
    2020 H7 (Lemmon)
    Gregory Leonard discovered an asteroidal object of 21st magnitude in images taken with the 1.5m reflector of the Mt Lemmon Survey on April 29.42. It was placed on the PCCP as C2PJ842. Follow-up astrometry by other observers, including Peter Birtwhistle, showed cometary features. [CBET 4777, MPEC 2020-K107, 2020 May 21]. The comet is at perihelion at 4.4 au in 2020 June.
    2020 H8 (PanSTARRS)
    PanSTARRS 2 discovered a 20th magnitude object in images taken with the 1.8m Ritchey-Chretien on April 30.58. The MPEC says it was reported as an NEO candidate, whilst the CBET says it was reported as cometary. It was placed on the PCCP as P20ZU1k. [CBET 4778, MPEC 2020-K110, 2020 May 21] The comet is at perihelion at 4.7 au in 2020 June.
    A/2020 H9 [A/PanSTARRS]
    PanSTARRS 1 discovered a 22nd magnitude object in images taken with the 1.8m Ritchey-Chretien on April 28.42. It was placed on the PCCP as P20ZMLy. No cometary activity was detected. [MPEC 2020-K165, 2020 May 25] The object was at perihelion at 2.6 au in 2019 December and is in a retrograde near parabolic orbit.
    2020 HB11 [A/Lemmon]
    The Mt Lemmon Survey discovered an asteroidal object of 22nd magnitude in images taken with the 1.5m reflector of on April 18.32. It was placed on the PCCP as C2KGVW2, however no cometary features were detected. [MPEC 2020-K199, 2020 May 27]. The obect is at perihelion at 4.8 au in 2020 August and has a retrograde orbit with a period of around 70 years.  JPL classify it as a Centaur.
    2020 J1 (SONEAR)
    Christovao Jacques reported a 17th magnitude object in images taken on May 1.27 with the "Southern Observatory for Near Earth Research" (SONEAR) 0.28-m f/2.2 astrograph at Oliveira, Brazil. Cometary features were then reported in follow-up astrometry. [CBET 4769, MPEC 2020-J37, 2020 May 4] The comet is at perihelion at 3.3 au in 2021 April.
    2020 K1 (PanSTARRS)
    PanSTARRS 2 discovered a 20th magnitude object in images taken with the 1.8m Ritchey-Chretien on May 17.51. The MPEC says it was reported as an NEO candidate, whilst the CBET says it was reported as cometary. It was placed on the PCCP as P210rpD. PanSTARRS then found pre-discovery images from April. [CBET 4779, MPEC 2020-K111, 2020 May 21] The comet is at perihelion at 3.1 au in 2023 June.
    2020 K2 (PanSTARRS)
    PanSTARRS 2 discovered a 20th magnitude comet in images taken with the 1.8m Ritchey-Chretien on May 21.57. It was placed on the PCCP as P210KhL. [CBET 4781, MPEC 2020-K155, 2020 May 24] The comet was at perihelion at 8.2 au in 2018 December.
    2020 K3 (Leonard)
    Gregory Leonard discovered a comet of 18th magnitude in Catalina Sky Survey images taken with the 0.68m Schmidt on May 22.45. It was placed on the PCCP as C184DV1 and quickly confirmed by Peter Birtwhistle and other astrometrists. [CBET 4782, MPEC 2020-K159, 2020 May 25]. The comet was close to perihelion at 1.6 au.  It briefly appeared again on the PCCP as A10nJin at the end of June.
    2020 K4 (PanSTARRS)
    PanSTARRS 1 discovered a 20th magnitude comet in images taken with the 1.8m Ritchey-Chretien on May 20.53. It was placed on the PCCP as P110DoO. [CBET 4783, MPEC 2020-K162, 2020 May 25] The comet was at perihelion at 1.8 au in 2020 March.
    2020 K5 (PanSTARRS)
    PanSTARRS 1 discovered a 21st magnitude comet in images taken with the 1.8m Ritchey-Chretien on May 25.51. It was placed on the PCCP as P110Z97. THe PanSTARRS team found pre-discovery images from both PanSTARRS telescopes in April and from PanSTARRS 2 in May. [CBET 4785, MPEC 2020-K205, 2020 May 28] The comet will reach perihelion at 1.5 au in 2021 June.
    2020 K6 (Rankin)
    David Rankin discovered a comet of 21st magnitude in images taken with the 1.5m reflector on May 26.37 during the Mt Lemmon Survey. It was placed on the PCCP as C2W2MW2. [CBET 4788, MPEC 2020-L03, 2020 June 1]. The comet is at perihelion at 6.0 au in 2021 August.
    2020 K7 (PanSTARRS)
    PanSTARRS 1 discovered a 20th magnitude comet in images taken with the 1.8m Ritchey-Chretien on May 30.55. It was placed on the PCCP as P111acy. [CBET 4790, MPEC 2020-L09, 2020 June 2] The comet will reach perihelion at 5.7 au in 2021 October.
    2020 K8 (Catalina-ATLAS)
    The Catalina Sky Survey submitted observations of objects in images taken with the 0.68m Schmidt on May 25.43, 28 and 29. The ATLAS (Asteroid Terrestrial-impact Last Alert System) team submitted observations of a potential NEO in images taken with the 0.5m Schmidt at Haleakala on June 7.56. Rob Weyrk suggested that these were all the same object and it was posted on the PCCP as A10nc78. Cometary features were then detected by several astrometrists, both amateur and professional. [CBET 4796, MPEC 2020-L46, 2020 June 12] The comet is at perihelion at 0.5au in 2020 September. Although the provisional absolute magnitude is quite faint, visual observations often produce brighter estimates. The comet could be 13th magnitude or brighter around the time of perihelion.  This proved to be the case and JJ Gonzalez observed it at 10.3 in his 0.20m SCT on August 25. 
    2020 K9 (P/Lemmon-PanSTARRS)
    The Mt Lemmon Survey discovered an asteroidal object of 21st magnitude in images taken with the 1.5m reflector of on May 22.43. PanSTARRS 1 discovered a 20th magnitude asteroid in images taken with the 1.8m Ritchey-Chretien on May 26.58. On June 16 Gareth Williams linked the two objects, along with a third reported by ATLAS on May 29. It was placed on the PCCP as C2UM9W2, and cometary features were detected. [CBET 4797, MPEC 2020-M26, 2020 June 18]. The comet is at perihelion at 2.8 au in 2021 February and has a period of around 8.6 years. The comet passed 0.06 au from Jupiter in 2016 April.
    2020 KU7 [A/PanSTARRS]
    PanSTARRS 1 discovered an asteroid in images taken with the 1.8m Ritchey-Chretien on June 14.3. The object, classified by JPL as an Trans-Neptunian Object and the MPC as a Centaur, is at perihelion at 4.2 au in 2021 March and has a retrograde orbit with a period of around 200 years. It has a Jupiter MOID of 0.26 au. It was placed on the PCCP as P111lTq. No cometary activity has been detected.
    2020 M1 (P/PanSTARRS)
    PanSTARRS 1 discovered a 21st magnitude comet in images taken with the 1.8m Ritchey-Chretien on June 17.37. There were prediscovery PanSTARRS observations from May 24 and 28. It was placed on the PCCP as P111H4A. [CBET 4800, MPEC 2020-M76, 2020 June 23] The comet was at perihelion at 2.7 au in 2019 December and has a period of 11 years.  The orbit has a Jupiter MOID of 0.02 au and the comet will pass 0.69 au from the planet in 2021 October.
    2020 M2 (P/Lemmon)
    Hirohisa Sato recovered 2012 SB6 in images taken with the 0.51-m f/6.8 iTelescope astrograph at Siding Spring on June 29.82, with confirming images with the 0.43-m f/6.8 iTelescope astrograph at Mayhill the following day. The linked orbit shows that the comet passed 0.14 au from Jupiter in 1928 September, just before its 1928 perihelion; prior to that close approach, the orbit had q = 4.58 au and e = 0.20. [CBET 4807, MPEC 2020-N01, 2020 July 1]
    2020 M3 (ATLAS)
    The ATLAS (Asteroid Terrestrial-impact Last Alert System) team discovered a 19th magnitude object in images taken with the 0.5m Schmidt at Mauna Loa on June 27.58. It was posted on the PCCP as A10nHge and subsequently noted as cometary by several astrometrists. [CBET 4808, MPEC 2020-N11, 2020 July 3]. The comet is at perihelion at 1.3 au in 2020 October and has a period of around 140 years. It may reach around 13th magnitude near the time of perihelion.
    A/2020 M4 [A/PanSTARRS]
    PanSTARRS 2 discovered a 22nd magnitude object in images taken with the 1.8m Ritchey-Chretien on June 17.40. It was placed on the PCCP as P211FjA, but then transferred to the NEOCP. No cometary activity was detected. [MPEC 2020-O13, 2020 July 18] The object is at perihelion at 6.0 au in 2020 November and is in a retrograde near parabolic orbit.
    2020 M5 (ATLAS)
    The ATLAS (Asteroid Terrestrial-impact Last Alert System) team discovered a 19th magnitude object in images taken with the 0.5m Schmidt at Mauna Loa on June 30.56. It was posted on the PCCP as A10nMaI and subsequently noted as cometary by several astrometrists. Pre-discovery PanSTARRS images were reported from 2019 August, October and November but was not at that time determinable as a comet due to its faintness. [CBET 4814, MPEC 2020-O30, 2020 July 19]. The comet is at perihelion at 3.0 au in 2021 August.
    2020 ML1 [A/PanSTARRS]
    PanSTARRS 1 discovered an asteroid in images taken with the 1.8m Ritchey-Chretien on June 16.36. The object, classified by JPL as an Trans-Neptunian Object, was at perihelion at 2.5 au in 2020 April and has a perpendicular orbit with a period of around 300 years. It was placed on the PCCP as P111w33. [MPEC 2020-M73, 2020 June 23] No cometary activity has been detected.
    2020 N1 (PanSTARRS)
    PanSTARRS 1 discovered a 21st magnitude object in images taken with the 1.8m Ritchey-Chretien on July 3.58, with follow-up observations showing it to be a comet. PanSTARRS also found a pre-discovery image from July 1. It was placed on the PCCP as P112nlR. [CBET 4815, MPEC 2020-O31, 2020 July 19] The comet is at perihelion at 1.3 au in 2021 March, when it could be 14th magnitude or perhaps brighter.
    2020 N2 (ATLAS)
    The ATLAS (Asteroid Terrestrial-impact Last Alert System) team discovered an 18th magnitude object in images taken with the 0.5m Schmidt at Mauna Loa on July 13.54. It was posted on the PCCP as A10o9AK and subsequently noted as cometary by several astrometrists. [CBET 4818, MPEC 2020-O100, 2020 July 25]. The comet is at perihelion at 1.8 au in 2020 August.
    2020 O1 (P/Lemmon-PanSTARRS)
    PanSTARRS 1 discovered a 21st magnitude comet in images taken with the 1.8m Ritchey-Chretien on July 20.44, with pre-discovery images from May, June and earlier in July. Independent observations of an asteroid on July 19.41 were reported from Mt Lemmon. It was placed on the PCCP as P112Sqo. [CBET 4820, MPEC 2020-P07, 2020 August 2] The comet was at perihelion at 2.3 au in 2020 May and has a period of around 4.3 years.
    2020 O2 (Amaral)
    Leonardo Amaral, Rio de Janeiro, discovered an 18th magnitude comet in images taken with his 0.3m f/4 reflector at Campo dos Amarais Observatory on July 23.97. It was placed on the PCCP as OCA9957. [CBET 4822, MPEC 2020-P10, 2020 August 2] The comet is at perihelion at 4.9 au in 2021 August.
    2020 O3 (P/PanSTARRS)
    PanSTARRS 1 discovered a 21st magnitude comet in images taken with the 1.8m Ritchey-Chretien on July 28.50, with pre-discovery images from PanSTARRS 2 earlier in July. It was placed on the PCCP as P113eDd. [CBET 4823, MPEC 2020-P11, 2020 August 2] The comet is at perihelion at 4.2 au in 2020 December and has a period of around 10 years.
    2020 O4 (P/PanSTARRS)
    Syuichi Nakano noticed that recovery observations of 2013 O2 had been published in recent MPECs listing observations of comets (P19, Q175 and R04). The earliest observations (July 30.36) were by Mt Lemmon, with several other observers/observatories including Werner Hasubick at Buchloe also observing the comet. Nakano then computed a linked orbit and an MPEC was issued giving a designation, followed by the CBET. [MPEC 2020-R32, CBET 4844, 2020 September 7]
    2020 OR5 [A/PanSTARRS]
    PanSTARRS 1 discovered an asteroid in images taken with the 1.8m Ritchey-Chretien on July 17.54. It was placed on the PCCP as P112FhO. Prediscovery images from PanSTARRS 1 and 2 were found from 2018 and 2019. [MPEC 2020-O164, 2020 July 29] The object, classified by JPL as a Centaur asteroid, is at perihelion at 3.9 au in 2021 February and has a retrograde orbit with a period of around 16 years. No cometary activity has been detected.
    2020 OS5 [A/PanSTARRS]
    PanSTARRS 1 discovered an asteroid in images taken with the 1.8m Ritchey-Chretien on July 21.47. It was placed on the PCCP as P112YSl. [MPEC 2020-O165, 2020 July 29] The object, classified by JPL as a Centaur asteroid, is at perihelion at 2.2 au in 2020 October and has a retrograde orbit with a period of around 18 years. No cometary activity has been detected.
    2020 OP7 [A/PanSTARRS]
    PanSTARRS 1 discovered an asteroid in images taken with the 1.8m Ritchey-Chretien on July 21.4. It was placed on the PCCP as P112YDn. The object, classified by JPL as a Centaur asteroid, is at perihelion at 3.0 au in 2020 October and has a near-perpendicular orbit with a period of around 150 years. No cometary activity has been detected.
    2020 P1 (NEOWISE)
    An approximately 19th magnitude comet was discovered from the NEOWISE satellite on August 2.63 It was posted on the PCCP as N00gzzu. Ground-based observers confirmed the cometary nature, reporting it as bright as 16th magnitude. [CBET 4825, MPEC 2020-P29, 2020 August 8] The comet is at perihelion at 0.3 au in 2020 October.  It will be a southern hemisphere object prior to perihelion.  Although potentially reaching 10th magnitude at perihelion, the observing circumstances are not good and the comet is unlikely to be observed visually unless it becomes much brighter than predicted.
    2020 P2 (P/Boattini)
    Nicolas Erasmus of The ATLAS (Asteroid Terrestrial-impact Last Alert System) team discovered a 19th magnitude object in images taken with the 0.5m Schmidt at Mauna Loa on August 11.58. It was posted on the PCCP as A10oYh3 and the next day deleted and reported on the "Previous NEO Confirmation Page Objects" as P/2020 P2. There was no MPEC or CBET linked to it at this point. CBET 4829 was issued on August 16. After posting on the PCCP, Hirohisa Sato had noted that it appeared to be a recovery of 2009 Q4, some 10' from the expected position. On August 18 it appeared on the PCCP as C30WCG2. On August 22 it again appeared on the PCCP as A10ptJX. These repeat appearances are perhaps a consequence of the continued failure to issue an MPEC.
    2020 P3 (ATLAS)
    The ATLAS (Asteroid Terrestrial-impact Last Alert System) team discovered a possible 19th magnitude comet in images taken with the 0.5m Schmidt at Mauna Loa on August 9.57. It was posted on the PCCP as A10oSF1 and confirmed by other astrometrists. The CBET gives a slightly different story, stating that it was initially reported as asteroidal by ATLAS and that the cometry nature was "withheld" until ATLAS had obtained confirming images with the 2.0m Faulkes Telescope North on August 10.6. [CBET 4830, MPEC 2020-Q1, 2020 August 16] The comet is at perihelion at 6.9 au in 2021 March
    2020 P4 (SOHO)
    Worachate Boonplod discovered a non group comet in SOHO LASCO C3 images on August 6.14, with additional fragments discovered on August 6.79 and August 7.50. Alan Watson found possible images in STEREO data from August 5. Michael Mattiazzo found prediscovery images in SOHO SWAN data from July 27 to August 1. Sam Dean used the measured positions to compute a preliminary orbit, which suggested that the comet was at perihelion at around 0.05 au on August 7.6 and was in a retrograde orbit. It might have been detectable from the ground at around 11th magnitude in late July. Using the criteria devised by Brian Marsden the comet should have been designated P1, but other logic has been used and it was designated in MPEC 2020-Q231 and CBET 4841 [2020 August 31]. The MPEC notes that the comet fragmented into three and gives elements for the three fragments at an epoch over two months prior to perihelion. The elements suggest that the comet was in a prograde orbit of moderate inclination, with perihelion at around 0.09 au about August 8. The perihelion distance differs by over 0.01 au between the components and the date by more than a day, though this is likely to be an artifact of the epoch used and the different arcs of observation.  The CBET gives elements for the major component with perihelion at 0.084 au on August 8.3. 
    2020 PV6 [A/PanSTARRS]
    PanSTARRS 1 discovered an asteroid in images taken with the 1.8m Ritchey-Chretien on August 13.51. It was placed on the PCCP as P113P9h. [MPEC 2020-Q118, 2020 August 20] The object, classified by JPL as a Centaur asteroid, is at perihelion at 2.3 au in 2020 October and has a retrograde orbit with a period of around 250 years. No cometary activity has been detected.
    2020 Q1 (Borisov)
    Gennady Borisov discovered an 18th magnitude comet in images taken with the MARGO 0.65-m f/1.5 astrograph at Nauchnij, Crimea on August 17.97. It was placed on the PCCP as gb00267 and quickly confirmed by other astrometrists. [CBET 4836, MPEC 2020-Q109, 2020 August 20] The comet was near perihelion at 1.3 au. The comet will brighten as it is still approaching the Earth, but will probably not get within visual range.  It did however, and JJ Gonzalez observed it at 11.6 in his 0.20m SCT on August 25.  It will be around 11th magnitude and circumpolar from the UK when at its brightest in September.
    2020 Q2 (PanSTARRS)
    PanSTARRS 1 discovered a 21st magnitude comet in images taken with the 1.8m Ritchey-Chretien on August 22.40. It was placed on the PCCP as P114AC8. The PanSTARRS team found pre-discovery images from June, July and August. [CBET 4839, MPEC 2020-Q204, 2020 August 27] The comet was at perihelion at 5.4 au in 2020 February and has a period of around 36 years.  The orbit has a Jupiter MOID of 0.4 au, but there have been no recent encounters.
    2020 QN6 [A/PanSTARRS]
    PanSTARRS 1 discovered a 22nd magnitude asteroid in images taken with the 1.8m Ritchey-Chretien on August 18.29. It was placed on the PCCP as P114meJ and also appeared as P114vi8. The object, classified by JPL as a Trans-Neptunian Object, is near perihelion at 4.8 au and has a highly inclined orbit with a period of several thousand years. No cometary activity has been detected.
    2020 QO6 [A/PanSTARRS]
    PanSTARRS 1 discovered a 22nd magnitude asteroid in images taken with the 1.8m Ritchey-Chretien on August 18.38. It was placed on the PCCP as P114lxn. The object, classified by JPL as a Centaur asteroid, is at perihelion in 2020 November at 2.4 au and has a highly inclined orbit with a period of around 70 years. No cometary activity has been detected.
    2020 R1 (P/PanSTARRS)
    PanSTARRS 1 discovered a 20th magnitude comet in images taken with the 1.8m Ritchey-Chretien on September 9.50. It was placed on the NEOCP with an unknown designation. Richard Weryk of the PanSTARRS team found pre-discovery images from 2013 August, 2014, 2015, 2016 and earlier in 2020. The MPC then gave it an asteroidal designation of 2013 PA104 and deleted it from the NEOCP but did not place it on the list of previous designations. In the meantime the Mt Lemmon Survey reported the detection of a comet on September 10.38 and this was placed on the PCCP as C35DT72. When follow-up observations were made it became obvious that the two objects were the same, but apart from admitting the goof, the MPC has not given further explanation of what went wrong. [CBET 4845, MPEC 2020-R101, 2020 September 13] The comet is at perihelion at 2.1 au in 2021 February and has a period of 6.7 years. 
    2020 R2 (PanSTARRS)
    PanSTARRS 2 discovered a 21st magnitude object in images taken with the 1.8m Ritchey-Chretien on September 12.31. It was placed on the PCCP as P215xsD. Richard Weryk found pre-discovery images in PanSTARRS data from August 18, 29 and September 7. There were also Mt Lemmon images from September 6. [CBET 4846, MPEC 2020-R119, 2020 September 14] The comet is at perihelion at 4.7 au in 2022 February.
    2020 R3 (P/McNaught)
    Erwin Schwab recovered comet 2006 H1 in images taken with the 0.8-m f/3 Schmidt reflector at Calar Alto, Spain. on September 11.09. The indicated delta-T correction to the prediction, by Gareth Williams, on MPC 58118 is -0.15 days. [CBET 4847, MPEC 2020-R159, 2020 September 14]
    2020 R4 (ATLAS)
    The ATLAS (Asteroid Terrestrial-impact Last Alert System) team discovered a 19th magnitude comet in images taken with the 0.5m Schmidt at Mauna Loa on September 12.50. It was posted on the PCCP as A10qhkr and subsequently confirmed as cometary by several astrometrists. There were pre-discovery images of the comet in Catalina Sky Survey data from August and PanSTARRS from August and September. [CBET 4849, MPEC 2020-S33, 2020 September 16]. The comet is at perihelion at 1.0 au in 2021 March.  Unfortunately it is not an optimum return, however the comet might reach 13th magnitude post perihelion when it approaches us to 0.5au.  It has a rather faint absolute magnitude, but these comets often appear brighter to visual observers.
    2020 R5 (P/PanSTARRS)
    PanSTARRS 2 discovered a 20th magnitude comet in images taken with the 1.8m Ritchey-Chretien on September 14.43. It was posted on the PCCP as P2165ij and subsequently confirmed as cometary by several astrometrists. The PanSTARRS team found pre-discovery images going back to 2019 May and there were also Mt Lemmon images from 2020 July. [CBET 4851, MPEC 2020-S99, 2020 September 19] The comet was at perihelion at 3.4 au in 2020 May and has a period of 11 years. It passed around 0.88 au from Jupiter in 2006 November.
    2020 R6 (Rankin)
    David Rankin discovered a comet of 20th magnitude in images taken with the 1.5m reflector on September 15.42 during the Mt Lemmon Survey. It was placed on the PCCP as C370K42. [CBET 48xx, MPEC 2020-S148, 2020 September 22]. The comet was at perihelion at 2.8 au in 2019 September.
    2020 S1 (P/PanSTARRS)
    PanSTARRS 1 discovered a 22nd magnitude comet in images taken with the 1.8m Ritchey-Chretien on September 16.42. It was posted on the PCCP as P116j2k. The PanSTARRS team found pre-discovery images going back to 2020 July and there were also Mt Lemmon images from the day before discovery. [CBET 4853, MPEC 2020-S102, 2020 September 19] The comet is at perihelion at 2.9 au in 2021 January and has a period of around 15 years.
    2020 S2 (PanSTARRS)
    PanSTARRS 1 discovered a 21st magnitude comet in images taken with the 1.8m Ritchey-Chretien on September 16.33. It was posted on the PCCP as P116gz6. The PanSTARRS team found pre-discovery images going back to 2020 August and there were also Mt Lemmon images from earlier in September. [CBET 4854, MPEC 2020-S105, 2020 September 20] The comet is at perihelion at 1.8 au in 2020 DEcember and has a period of around 30 years.
    2020 S3 (Erasmus)
    Nicolas Erasmus of the ATLAS (Asteroid Terrestrial-impact Last Alert System) team discovered an 18th magnitude comet in images taken with the 0.5m Schmidt at Mauna Loa on September 17.61. It was posted on the PCCP as A10qDsR and subsequently confirmed as cometary by several astrometrists, including section director Nick James. [CBET 4855, MPEC 2020-S119, 2020 September 20]. The comet is at perihelion at 0.4 au in 2020 December.  Unfortunately it is not an optimum apparition, and although the comet might reach 11th magnitude at perihelion it is then in conjunction. It is only likely to be seen by visual observers from equatorial latitudes in November.  It has a rather faint absolute magnitude, but these comets often appear brighter to visual observers.
    Ephemerides of current comets are available on the CBAT ephemeris page and positions of newly discovered comets are on the Possible Comet Confirmation Page.
    More information on LINEAR. A list of comets discovered by selected search programs.
    The Northumberland refractor is the telescope that was used in the search for Neptune. It now has a 0.30-m f20 doublet lens which gives a stellar limiting magnitude of around 15 at the zenith on good nights. The Thorrowgood refractor was built in 1864 and has a 0.20-m f14 doublet lens; it is currently out of action as the dome has stuck.
    Published by Jonathan Shanklin. Jon Shanklin - jds@ast.cam.ac.uk