BAA Comet Section : Periodic Comets 300 - 399

Updated 2024 November 5

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.

The comet was recovered by M. Masek, J. Cerny, J. Ebr, M. Prouza, P. Kubanek, M. Jelinek, K. Honkova and J. Jurysek at the Pierre Auger Observatory, Malarque with the 0.3m reflector on April 9.39. [MPEC 2014-G70, 2014 April 10]. The comet returns to perihelion 0.1 days earlier than predicted.

The comet can make close approaches to Venus, Earth and Mars. Its last close approach to Earth was at the discovery apparition in 2005, when it came to 0.10 au and in 2036 it will approach to 0.06 au. It will approach within 0.08 au of Mars in 2132 and approached Venus to 0.09 au in 1957.  The June epsilon Ophiuchid meteor shower was active between 2019 June 19 and 26 and this shower is associated with the comet.

2001 BB50 (P/LINEAR-NEAT) was recovered in images from PanSTARRS taken on 2014 May 17.28, with earlier images taken at the SATINO remote observatory, Haute Province on 2014 March 1.93. The comet will return to perihelion 1.76 days earlier than predicted and has a period of 13.7 years.

K. Lawrence, Jet Propulsion Laboratory, reports the discovery by the NEAT project of a 19th magnitude comet on 2003 October 22.29. Observations by J. Young at Table Mountain on October 23.2 UT show a 3" coma with a short, broad, fan-shaped tail about 8" long spanning p.a. 255-285 deg. [IAUC 8230, 2003 October 23]

2003 U3 (P/NEAT) was recovered in images taken at the ESA Optical Ground Station in Tenerife with the 1.0m reflector by P Ruiz. The comet will return to perihelion 1.80 days earlier than predicted and has a period of 11.4 years.    [MPEC 2014-L12, 2014 June 2]

Michel Ory is a Swiss amateur astronomer and president of the Société jurassienne d'astronomie, which has a well equipped observatory in the foothills of the Jura.

The comet passed 0.3 au from Jupiter in November 2005, before which the perihelion distance was a little larger.

2008 Q2 was recovered by Hidetaka Sato in images taken with the iTelescope 0.51m astrograph at Siding Spring on 2014 June 2.79. The comet is very close to the prediction by B. G. Marsden on MPC 65935. It has a period of 5.8 years.  [MPEC 2014-M10, CBET 3906, 2014 June 18].

In 2021 January it briefly appeared on the PCCP as C4PEAU2.

B. Skiff, Lowell Observatory, reports his discovery of a comet on LONEOS images obtained on Nov. 4.1 UT with the 0.59-m Schmidt telescope, the object showing a moderately condensed coma of diameter 25" and a weak tail 50" long in p.a. 75 deg. Following posting on the "NEO Confirmation Page", B. L. Stevens (Las Cruces, NM, 0.3-m Schmidt-Cassegrain telescope) reports that his CCD images taken on Nov. 4.2 show a 30" tail in p.a. 55 deg. [IAUC 8426, 2004 November 4]

Gareth Williams found images of 2004 V1 (P/Skiff) in images taken taken with the PanSTARRS 1 1.8m Ritchey-Chretien on July 3.51. The comet will return to perihelion 0.32 days earlier than predicted and has a period of 9.9 years.  [CBET 3918, MPEC 2014-N43, 2014 July 7]

An apparently asteroidal object reported by LINEAR, and posted on the NEO Confirmation Page, was found to be apparently cometary on CCD images taken by P. Birtwhistle (Great Shefford, U.K., 0.30-m reflector; very faint tail about 10" long in p.a. approximately 270-280 deg on July 31.10 and Aug. 2.08 UT; mag 18.1 and coma diameter about 5" on Aug. 2.08), by J. Ticha and M. Tichy (Klet, 1.06-m KLENOT telescope; diffuse with a wide tail in p.a. 260 deg on Aug. 3.01), and by J. McGaha (near Tucson, AZ; possible tail spike 5" long in p.a. 300 deg on Aug. 3.38 with a 0.30-m reflector; possible fan-shaped tail 5" long in p.a. 260 deg on Aug. 5.33 with a 0.62-m reflector). The preliminary orbital elements indicate that the comet passed 0.3 au from Jupiter in Nov. 1979. [IAUC 8174, 2003 August 5]

2003 O3 (P/LINEAR) was recovered by Hidetaka Sato in images taken with the iTelescope 0.51m astrograph at Siding Spring on June 21.77. The comet was missed at its 2009 return and is close to the prediction in the 2014 ICQ Handbook. It has a period of 5.5 years with perihelion at 1.3 au.  [MPEC 2014-N76, CBET 3922, 2014 July 14]

A team of observers at the European Space Agency's Optical Ground Station recovered 2000 QJ46 (P/LINEAR) with the 1.0m reflector on 2014 July 25.15. The indicated correction to the prediction by B. G. Marsden on MPC 75735 is Delta(T) = -0.24 day.  [CBET 3923, MPEC 2014-O44, 2014 July 27] The comet has a period of 14 years and reaches perihelion at 1.9 au in December.

The comet is one of those suspected to have undergone nuclear splitting according to the list of Marcos & Marcos [Dynamically correlated minor bodies in the outer solar system, MNRAS, 474, 838, 2018 February]. They link it to 16P/Brooks.

A team of observers at the European Space Agency's Optical Ground Station recovered 1997 T3 (P/Lagerqvist-Carsenty) with the 1.0m reflector on 2014 July 29.08. The indicated correction to the prediction by B. G. Marsden on MPC 79348 is Delta(T) = -1.28 days. [CBET 3925, MPEC 2014-O65, 2014 July 30] The comet has a period of 17 years and reaches perihelion at 4.2 au in 2015 May.

Krisztian Sarneczky recovered 2005 Q4 (P/LINEAR) with a 0.6m Schmidt on 2014 August 23.00, with PanSTARRS images from the same night later found by Gareth Williams. The indicated correction to the prediction by Gareth Williams on MPC 75706 is Delta(T) = -0.26 day.  [CBET 3937, MPEC 2014-Q39, 2014 August 24] The comet has a period of 9.4 years and reaches perihelion at 1.7 au in 2015 February.

Krisztian Sarneczky recovered 2006 S6 (P/Hill) with a 0.6m Schmidt at the Piszkesteto Station of Konkoly Observatory on 2014 August 24.98. The indicated correction to the prediction by Gareth Williams on MPC 79348 is Delta(T) = -0.32 day.  [CBET 3938, MPEC 2014-Q53, 2014 August 26] The comet has a period of 8.5 years and reaches perihelion at 2.4 au in 2015 April.

A paper by Dave Jewitt et al in Astronomical Journal suggests that the comet is a close binary with a period of about 0.8 days and a mass ratio of about 1:6. One of the components may be a fast rotator, which could explain the behaviour in 2013, when there were nine dust ejection events over about 250 days, which could have been caused by landsliding.

2001 Q11 (P/NEAT) was recovered in images taken by Eric Christensen at Mt Lemmon with the 1.5m reflector on September 6.45.  After the object was posted on the PCCP, Hidetaka Sato was able to find the comet in images taken on July 28.82.  The comet will return to perihelion 0.68 days earlier than predicted and has a period of 6.4 years.  It was discovered by Maik Meyer in 2010 in images taken in 2001, though no images could be found from the 2007 return. [CBET 3971, MPEC 2014-R91, 2014 September 12]

With an improved orbit, it was linked to an object found in LONEOS images from September and November 2003 and was designated 2003 S10 for that return. [MPEC 2014-U24, 2014 October 20]

The comet was at perihelion at 2.4 au in 2014 August and has a period of 5.6 years.  It is a Main Belt Comet.

1997 G1 (P/Montani) was recovered on October 13.31 at the Steward Observatory, Kitt Peak by Terry Bressi and A F Tubbiolo with the 0.9m reflector.

An apparently asteroidal object discovered by LONEOS, designated 2004 VR_8 (cf. MPS 118755, MPEC 2004-V48), was found to show a 10"-diameter coma and a tail 16" long in p.a. 140 deg on R-band CCD observations taken by C. W. Hergenrother (Lunar and Planetary Laboratory) with the 1.54-m Kuiper reflector at Catalina on November 19.3 UT. Also, A. Nakamura (Kuma, Ehime, Japan) reports that 240-s unfiltered CCD frames taken with a 0.60-m reflector on December 8.55 and 9.55 shows to object's image to be slightly 'softer' than other field stars of similar brightness, and a possible very faint tail is visible to the southeast. [IAUC 8451, 2004 December 10]

A possible recovery of 2004 VR8 (P/LONEOS) with the 3.5m Apache Point reflector on 2013 November 6.15 was confirmed with the same telescope on 2014 December 8.09. The indicated correction to the prediction by G. V. Willliams on MPC 84327 is Delta(T) = -0.71 day. [CBET 4038, MPEC 2014-Y45, 2014 December 24]  Jose Gonzalez noted the comet in possible minor outburst on 2017 March 15.83 when he estimated it at 12.3, with a stellar condensation.

The comet approaches Jupiter every few orbits, most recently on 2007 August 22 when it passed 0.40 au from the planet. The encounter made small changes to the orbital elements and increased the orbital period to 11.2 years.

2005 RV25 (P/LONEOS-Christensen) was recovered on 2014 October 22.98 at the ESA Optical Ground Station, Tenerife by Diana Abreu with the 1.0m reflector. The recovery was confirmed by J D Armstrong with the Faulkes-North   [CBET 40nn, MPEC 2014-W19, 2014 November 19]  The comet has perihelion at 3.6 au in 2015 October and a period of 8.9 years. The perihelion date was around xx days earlier than those published for the equinox of perihelion.

PanSTARRS recovered P/2010 K2 in images taken with the 1.8m Ritchey-Chretien on 2015 January 26.46, with further images on March 18.35. The comet now has a period of 5.1 years and will reach perihelion 3.2 days earlier than previously predicted. It passed 0.71 au from Jupiter in 2012 November.

1994 N2 (P/McNaught-Hartley) was recovered by PanSTARRS in images taken with the 1.8m Ritchey-Chretien on 2014 June 29.32, though it took further images taken at the MASTER-SAAO Observatory, Sutherland with the 0.4m reflector on 2015 March 31.1 to confirm the recovery. The comet reaches perihelion at 2.45 au in October and has a period of 20.6 years.

5 visual observations received so far suggest a preliminary light curve of m = 9.0 + 5 log d + [10] log r

An object found in infra-red images from the NEOWISE satellite on 2015 April 5.67 was identified as the return of 2008 S1 (P/Catalina-McNaught) by Gareth Williams.  The indicated correction to the prediction on MPC 79350 is Delta(T) = -0.11 day.  The comet reaches perihelion at 1.20 au in 2015 July and has a period of 6.8 years.

R. H. McNaught reports his discovery of a comet on CCD images taken by himself with the 0.5-m Uppsala Schmidt telescope at Siding Spring on Sept. 2.4 UT, when the object was diffuse with a hint of a tail to the southeast. Images taken by McNaught with the Siding Spring 1.0-m f/8 reflector on Sept. 4.4 show the comet to be diffuse with a 10" coma and a tail 15" long in p.a. 110 deg. [IAUC 8398, 2004 September 4]

J. Young (Table Mountain, 0.6-m reflector + CCD) reports that images taken in poor seeing (and at low altitude) on Sept. 6.13- 6.16 UT show a coma diameter of about 5". Additional CCD images by R. H. McNaught with the Siding-Spring 1.0-m reflector on Sept. 6.5 show an ill-defined center of brightness that is elongated in the direction of tail (and of the comet's motion). [IAUC 8400, 2004 September 6]

An apparently asteroidal object found on images taken with the Cerro Tololo 4-m reflector by L. Allen and D. James (measured by F. Valdes) was posted on the Minor Planet Center's NEOCP webpage and then announced on MPEC 2015-H82 with the minor-planet designation 2015 HC10. Gareth Williams, F. Manca, and P. Sicoli then each identified it with comet P/2004 R1. The comet was missed at its 2010 return. The indicated correction to the prediction by S. Nakano on MPC 79350 is Delta(T) = +5.0 days. 

Brian Marsden published a linked orbit on MPEC 2009-H56 [2009 April 26] and noted:

The above computation, using nongravitational parameters A1 = +0.0002, A2 = -0.0002, is based on work by R. Kracht. Despite the poor quality of the SOHO observations, a purely gravitational computation from the four apparitions appears to leave significantly systematic residuals.

The identification is by R. Kracht. The observations, all obtained with the LASCO C2 coronagraph, are on MPEC 2006-L20, 2004-M42 and 2008-O16. The The object passed 0.058 au from the earth on 2000 Jan. 13, 0.032 au from Mars on 2004 May 19 and 1.17 au from Jupiter on 2003 Feb. 1.

The comet was recovered by S. S. Sheppard with the Magellan-Baade telescope in images taken in 2015 March and April, but the recovery was first reported by Jim Scotti in images taken with the Spacewatch 1.8-m telescope at Kitt Peak on 2015 May 22.43. The indicated correction to the prediction by S. Nakano is Delta(T) = -0.03 day.  [CBET 4107, MPEC 2015-K101, 2015 May 26].  The Magellan-Baade images showed a tail, which was confirmed by CFH images, according to IAUC 9276 [2015 August 3].  This notes that the object is the fourth main belt comet to show recurrent activity when near perihelion after being inactive at aphelion. 

The comet was recovered at the 2021 return by Bruno Vauquelin at the Compustar Observatory, Rouen in images taken on 2021 July 31. In a paper published on arxiv in 2024 Mastropietro et al suggest that activity has declined at each succeeding perihelion passage since 2010 and that the nucleus has a radius of about 500m.

Hidetaka Sato recovered 2009 L2 with the 0.51m iTelescope at Siding Spring on 2015 May 11.38 with confirming images taken on June 9 and 10. [MPEC 2015-L28, 2015 June 10].

In 2018 Gary Kronk and Maik Meyer re-measured the positions of several X/ comets and found that X/1951 K1 was 325P.  The comet passed 0.34 au from Jupiter on 2013 February 28 and this has increased the perihelion distance to 1.43 au.  The linked orbit was finally published on MPEC 2019-F55 [2019 March 21].  It took over a year for this information to be published in a CBET, eventually appearing in CBET 4806 [2020 June 28].

Krisztian Sarneczky recovered 2007 V2 (P/Hill) with the 0.6m Schmidt at Piszkesteto Station of Konkoly Observatory on August 8.02. [CBET 4134, MPEC 2015-P21, 2015 August 10].

A possible comet found by PanSTARRS on August 6.39 was tentatively identified as 2002 Q1 (P/Van Ness) by Gareth Williams. Krisztian Sarneczky independently recovered the comet on images taken with the 0.6m Schmidt at Piszkesteto Station of Konkoly Observatory on August 10.87 by A Sodor. The indicated correction to the prediction by S. Nakano on MPC 79352 is Delta(T) = +1.5 days.  [CBET 4135, MPEC 2015-P24, 2015 August 11].

Alex Gibbs discovered an 18th magnitude comet during the Catalina Sky Survey with the 0.68m Schmidt on 2015 September 30.13. He suggested that it might be a recovery of P/LONEOS-Tucker, which had been missed at its 2007 return. Other astrometrists, including Peter Birtwhistle confirmed the comet, and Gareth Williams computed a linked orbit. The correction to the predicted time of perihelion in published elements for the return was -1.9 days. [CBET 4146, MPEC 2015-T06, 2015 October 5]

An apparently asteroidal object was discovered by the LINEAR project on 2003 November 18 (observed on only two nights) and given the designation 2003 WC_7 (MPS 91151). The object was discovered independently on January 31 by the Catalina Sky Survey and then posted on the NEO Confirmation Page. As a result, it has been found to show cometary appearance on CCD exposures taken by J. Young (Table Mountain, 0.6-m reflector, Feb. 1.15 UT; very diffuse coma of mag 17.5 and diameter 5", very little central condensation, and a straight, narrow 10" tail in p.a. 345 deg) and by G. J. Garradd and R. H. McNaught (Siding Spring, 1.0-m f/8 reflector, Feb. 1.46; coma diameter 3".5 in 2".5 seeing; no obvious tail visible in five co- added 40-s frames). [IAUC 8280, 2004 February 1]

PanSTARRS discovered what was thought to be an unknown 20th magnitude comet on October 10.53, though the discovery report did suggest that it might be a recovery of 2003 WC7 (P/LINEAR-Catalina). Further astrometry confirmed the identification. The indicated correction to the prediction by G. V. Williams on MPC 79352 is Delta(T) = +0.70 day; the indicated correction to the prediction by S. Nakano in the ICQ's 2015 Comet Handbook is Delta(T) = +0.37 day. CBET 4148, MPEC 2015-T72, 2015 October 12]. The indicated ICQ Handbook does not appear to have any functional web links and is apparently not on the internet.

Krisztian Sarneczky recovered 1999 V1 on 2015 October 22.98 with the 0.6m Schmidt at Piszkesteto station of Konkoly Observatory. Following the observation he was able to identify images from September 13. The indicated correction to the prediction by Gareth Williams on MPC 84326 is Delta(T) = -0.74 day. [CBET 4155, MPEC 2015-U49, 2015 October 24]

The comet was magnitude 8.5 at discovery by Ikeya, and 8 the following day. It seemed to be brightening rapidly, as visual observation by Juan Jose Gonzalez on November 4.2 put it as bright as 7.6 in 10x50B. This may indicate that the comet is undergoing an outburst. This suggestion is partially confirmed by Ikeya's failure to spot the comet when he searched the discovery area on November 1.8. The coma expanded, and the comet had faded to around 12th magnitude by early December, much faster than a standard light curve would suggest.

The orbit is elliptic, with the comet at perihelion at 1.6 au in mid October and a period of around 5.3 years, as first suggested by Hirohisa Sato. Maik Meyer noted that there were similarities with the orbit of P/2010 B2, however once the orbit of 2010 V1 became better known Hirohisa Sato was able to show that the two orbits did not converge when computed back in time.

A paper by Masateru Ishiguro et al suggests that the outburst took place between 2010 October 31 and November 3 and was largely comprised of dust.  It was smaller than the outburst of 17P/Holmes, although the energy per unit mass was comparable.  They suggest crystallisation of amorphous water as a likely cause.

A 21st magnitude comet discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on 2015 December 31.52, and briefly on the PCCP, was identified with 2010 V1 (P/Ikeya-Murakami).  A secondary component was also discovered.  The comet returns to perihelion in 2016 March at 1.57 au and has a period of 5.4 years.  The indicated correction to the prediction by Gareth Williams on MPEC 2013-O31 is Delta(T) = +7.0 day.  [CBET 4230, MPEC 2016-A10, 2016 January 2]  The secondary component was designated 2010 V1-B [CBET 4231, MPEC 2016-A36, 2016 January 5], though there were no reports of it at that return.  The MPEC orbit for the secondary uses 435 observations, compared to 399 for the primary, both going back to 2010 November 3.  The two orbits are slightly different.  An orbit for a  tertiary component, designated 2010 V1-C, was published on January 26 and again quoted the use of observations back to 2010.  This MPEC also gave observations of a fourth component.  An orbit for a  fifth component, designated 2010 V1-E, was published on February 5, and a sixth, 2010 V1-F on February 9; again both quoted the use of observations back to 2010.  Orbits for further components, G, H, I and J have now been published.

Calculations by Zdenek Sekanina originally suggested that component B was the primary, and that component A separated at the last return, probably during the major outburst which began around 2010 November 1.  The tails of the two components lie in different directions, with that of component A in the orbital plane and composed of debris, whilst that of component B is closer to the anti-solar direction.  Further observations, including of a further component, D, now suggest that C is the main body as Zdenek Sekanina notes in CBET 4250 [2016 February 3].

Z. Sekanina, Jet Propulsion Laboratory, writes that recent developments (cf. MPEC 2016-B77) suggest that the 2010 outburst had more severe consequences for the comet's evolution than to accompany a single fragmentation event.  It triggered a fragmentation process that continued over an extended period of time after the outburst (and apparently is still continuing) -- a fairly common phenomenon among split comets that is referred to as "cascading fragmentation" (e.g., Sekanina 2002, Ap.J. 566, 577).  As already pointed out on CBET 4235, fragment A is not a primary component.  Since component B was the only other fragment known by Jan. 4, it was the candidate for the primary due to its location, but not by its very diffuse appearance.  The subsequent detection of fragment C (MPEC 2016-B77), about 12"-13" east of component B on Jan. 8 and 15"-16" on Jan. 11-19, resolved this ambiguity: nucleus C is the primary, the presumably most-massive piece -- though barely active until several days ago -- of the pre-outburst parent comet, unless yet another persistent fragment should still be detected to the east of component C.  The computations suggest that companion A separated from the parent most probably in early November 2012 (with an uncertainty of +/- 2 months). at a rate of 0.36 +/- 0.04 m/s, and was subjected to a differential nongravitational deceleration of 5.2 +/- 0.6 units of 10^{-5} the solar gravitational acceleration.  This solution fits the 12 most consistent offsets of A from C between Jan. 8 and 29 moderately better than a solution forcing the fragmentation time to coincide with the time of the 2010 outburst; it is suggested that component A should survive beyond the 2016 perihelion.  The histories of companions B (probably a cluster of sub-fragments) and D cannot as yet be determined with confidence, except that these objects are likely to be more recent and less massive products of the fragmentation process than companion A.  For companion B, a very tentative solution, based only on the observations Jan. 11-29, suggests that it may have split off in the second half of 2013 or the first half of 2014.  The observations of B from Jan. 8 leave systematic residuals of 2" to 4" from this solution, and a more recent origin of B is plausible.  It is possible that the Jan. 8 astrometric positions of B refer instead to D, in which case component D would have separated only in mid-October 2015, some 150 days before perihelion and, being subjected to a deceleration of about 25 units, would be a short-lived fragment. 

The comet is one of those known to have undergone nuclear splitting according to the list of Marcos & Marcos [Dynamically correlated minor bodies in the outer solar system, MNRAS, 474, 838, 2018 February]. They consider that the multiple fragments are linked to 2010 B2 (P/WISE). David Jewitt notes  that the nucleus has a diameter of less than 280m and likely suffers from rotational instability as it has a rotation period of around 2 hours.

Cometary activity was detected at the 2016 return, though the comet has not yet been given a designation for this return.  Jose Gonzalez observed it in early March at 11th magnitude, considerably brighter than expected.

4 observation received so far suggest a preliminary  uncorrected light curve of m = 10.6 + 5 log d + [20] log r .  

The comet was independently recovered at the Piszkesteto Station of Konkoly Observatory on 2016 January 7.90 and at the European Space Agency's Optical Ground Station, Tenerife on January 10.10. [CBET 4237, MPEC 2016-A105, 2016 January 11] The indicated correction to the prediction by S. Nakano in the ICQ's 2014 Comet Handbook is Delta(T) = -0.36 day.

The comet was recovered at the European Space Agency's Optical Ground Station, Tenerife on 2016 January 10.26. [CBET 4253, MPEC 2016-C42, 2016 February 5] The comet was close to the predicted orbit.

Gareth Williams found astrometry of 2006 G1 in PanSTARRS data from 2016 January 18.57 and February 14. The comet reaches perihelion 0.1 days earlier than predicted. [CBET 4258, MPEC 2016-C201, 2016 February 15] (Note the very large number of MPECs issued in the first half of February !)

An apparently asteroidal object of 21st magnitude was discovered by PanSTARRS on 2016 April 10.58. It was linked to earlier observations and given a minor planet designation. Further PanSTARRS images taken in early June suggested that it was likely to be a comet. After their report had been received by the MPC, the MPC received a report from Erwin Schwab on the recovery of 2010 N1 (P/WISE) and he later noted the identity with the asteroid. The indicated correction to the prediction by S. Nakano for P/2010 N1 is Delta(T) = -0.65 day. [CBET 4283, MPEC 2016-L36, 2016 June 5] The comet is at perihelion at 1.65 au in 2016 July and now has a period of 6.0 years. It made a close (0.52 au) approach to Jupiter in 2013 June, which increased the perihelion distance from 1.49 au to its current value and also slightly lengthened the period.

The comet was recovered at the European Space Agency Optical Ground Station with the 1.0m reflector on 2016 July 2.18. It reaches perihelion 0.8 days earlier than predicted. [CBET 4288, MPEC 2016-N12, 2016 July 3/4]

Hirohisa Sato recovered the comet in images taken with the 0.5m iTelescope at Siding Spring on 2016 June 29.35. It reaches perihelion 0.2 days earlier than predicted. [CBET 4287, MPEC 2016-N13, 2016 July 3/4]

A 20th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on 2016 July 4.50. R Weyrk of the PanSTARRS team suggested that it might be an accidental recovery of 2008 T1 and this was confirmed by Gareth Williams. The comet reaches perihelion 0.3 days later than predicted. [CBET 4289, MPEC 2016-N27, 2016 July 5]

Brian Marsden noted on MPEC 2007-V52 [2007 November 6] that further [astrometric] observations of this comet were desirable.

An 18th magnitude comet discovered during the Catalina Sky Survey with the 0.68-m Schmidt on 2016 July 15.45 was found to be the first observed return of 2007 R3. The comet reaches perihelion 0.48 days earlier than predicted.

I had given a lecture in the centre of Cambridge and didn't get into the office until after 10:00 (11:00 BST). First I checked the emails, including several Antarctic ones which had data that needed processing. Then I had a look at various web pages, including the latest MPECs, finally I had a look at the SOHO real time movies. I first looked at C2; there were no obvious Kreutz objects but I noted something that appeared to be moving opposite to the stars. I quickly found that it was moving consistently and emailed Doug and the group with details of the possible object. I then checked C3 in case it was visible and downloaded the real-time gif images to measure the positions. I found that it came into view at 21:30 on July 30 and was visible until 03:30 on July 31, moving horizontally from right to left just above the level of the occulting disc and below the beehive cluster. At its brightest (00:06) it was around 7th mag. I think the biggest surprise is that no-one else had picked up this object! Subsequently the comet came into view again, on images from 05:54 till after 12:00. The apparent fading around 03:30 may be due to phase effects playing a part. If it was then between us and the sun it would have zero phase and be difficult to see. The phase effect partly explains why many Kreutz comets are seen during May as this is when they are on the far side of the Sun and fully illuminated.

The orbit was finally published on MPEC 2000-Q09 [2000 August 19], after Brian Marsden returned to the USA following the IAU meeting in Manchester. It seems that the IAU had commanded all three senior members of the CBAT to attend the meeting. The comet had been at perihelion on July 30.94 at a perihelion distance of 0.054 au. Potentially observable from the ground it is at an elongation of 50 degrees in late August, though at a magnitude of near 20. The orbit shows that it passed on the far side of the sun, so phase effects do not explain the fading.

Further to IAUC 7472, D. Hammer has provided measurements of a comet detected by the SOHO C2 and C3 instruments and found by J. D. Shanklin via the SOHO website. The reduced measurements and orbits by B. G. Marsden, together with a search ephemeris, are given on MPEC 2000-Q09. G. J. Garradd, Loomberah, N.S.W., reports that his search for this object around Aug. 21.4 UT, out to about 0.5 deg ahead of its predicted position, yielding nothing to mag about 18. [IAUC 7479, 2000 August 21]

     2000 UT           R.A. (2000) Decl.        MPEC
     July 30.221       8 21.5      +19 08       2000-Q09

A comet was discovered with the SOHO LASCO coronographs by Bo Zhou. It was a sungrazing comet of the Kracht group. (IAUC 8638, 2005 December 4)

Brian Marsden comments on MPEC 2005-X14 [2005 December 3]

It seems likely that the Kracht-group comet C/2005 W4 is a return of C/2000 O3 (cf. MPEC 2000-Q09), a suggestion made by S. Hoenig before the observations above were available. The orbital linkage utilizes just the C2 observations (those from July 30.89596 onward in the case of C/2000 O3); although only the first three C/2005 W4 observations were obtained with C2, the residuals of the C3 observations are not systematically displaced.

2011 E1 was a sungrazing comet of the Kracht group discovered by Rainer Kracht in C3 images. IAUC 9201 [2011 March 21] gives an orbit by Gareth Williams linking 2011 E1 with 2000 O3 and 2005 W4. The orbital solution requires non gravitational parameters. There is a possibility that the comet might be visible to ground based telescopes during late March and early April 2011, though it would certainly be fainter than 20th magnitude.

A Kracht group comet discovered by Worachate Boonplod in SOHO C2 imagery from July 1 was linked to 2000 O3, 2005 W4 and 2011 E1. The comet has a period of 5.3 years and shows non-gravitational motion. [MPEC 2016-P77, 2016 August 10, CBET 4308, 2016 August 26]

The comet is one of those suspected to have undergone nuclear splitting according to the list of Marcos & Marcos [Dynamically correlated minor bodies in the outer solar system, MNRAS, 474, 838, 2018 February]. They link it to 2002 S7 (P/SOHO), which itself is linked to 1996 X3 (SOHO) and 2008 N4 (SOHO).

An apparently asteroidal object reported independently by the NEAT (on September 24.18) and LONEOS (on September 27.16) projects has been found to show a nonstellar appearance in individual 30-s R-band images taken by A. Fitzsimmons and C. Snodgrass, Queen's University of Belfast, and O. Hainaut, European Southern Observatory (ESO), on 2004 Jan. 19.0 UT at the ESO 3.6-m New Technology Telescope (+ SUSI-2 camera). Fitzsimmons adds that co- addition of the frames shows an asymmetric coma of total mag 20.3 extending 1".7 in p.a. 130 deg. [IAUC 8274, 2004 January 23]

A 20th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on August 12.48. Michael Meyer and Gareth Williams identified it with 2003 SQ215, and also found earlier PanSTARRS images from July 7, along with others taken by S. Maticic with the Crni Vrh 0.6-m f/3.3 Deltagraph on August 9. [CBET 4302, MPEC 2016-P122, 2016 August 14] The comet is returning to perihelion some 5 days earlier than previously predicted and will be at perihelion at 2.3 au in 2017 January. It has a period of 12.8 years.

Krisztian Sarneczky recovered 2005 S3 (P/Read) with the 0.6m Schmidt at Piszkesteto Station of Konkoly Observatory on August 27.04. [CBET 4310, MPEC 2016-Q52, 2016 August 30]. The comet returns to perihelion 0.5 days earlier than predicted.

The comet was recovered by Krisztian Sarneczky and P Szekely with the 0.6m Schmidt at Piszkesteto Station of Konkoly Observatory on September 1.08.  It was not given a designation on the MPEC. It returns to perihelion 0.35 days earlier than predicted. [MPEC 2016-R19, 2016 September 2, CBET 4315, 2016 September 3 ]

Jim Scotti recovered the comet with the Spacewatch 1.8m reflector on January 26.52. It returns to perihelion in 2018 January. [CBET 4352, MPEC 2017-B123, 2017 January 29]

Further observations allowed linkage with an asteroid discovered by P A Wiegert with the 3.6m CFHT on 2007 September 14.27, and with an object in images from LONEOS in 1998 October.

H Sato recovered 2000 S1 (P/Skiff) on June 5.81 using the 0.51m i-Telescope at Siding Spring. The indicated correction to the prediction by S. Nakano in the ICQ's 2017 Comet Handbook is Delta(T) = -2.64 days. [CBET 4402, MPEC 2017-L51, 2017 June 6]

Krisztian Sarneczky and R. Konyves-Toth recovered 2009 S2 (P/McNaught) using the 0.60-m Schmidt telescope at the Piszkesteto Station of Konkoly Observatory. The indicated correction to the prediction by S. Nakano in the ICQ's 2017 Comet Handbook (p. H13) is Delta(T) = -0.06 day. [CBET 4404, MPEC 2017-M28, 2017 June 20]

Javier Licandro, G. P. Tozzi, and Tiina Liimets note:

On January 14 we obtained images of this object using the Nordic Optical Telescope in La Palma, and on Jan 15 we made the following report to the CBAT:"J. Licandro (Instituto de Astrofísica de Canarias, Spain), G. P. Tozzi (INAF, O. di Arcetri), and Tiina Liimets (Nordic Optical Telescope, NOT, Spain & Tartu Obs., Estonia) report the presence of an object, probably an asteroid, 2 arcsec to the East of P/2010 A2 (LINEAR). Six images of 5 minute exposure time each were obtained on Jan. 14 using ALFOSC (Andalucia Faint Object Spectrograph and Camera) on the 2.6m NOT telescope at the "Roque de los Muchachos" Observatory (La Palma, Canary Islands, Spain). Four images were obtained in the R band and two in the V band, starting 22:41 ending 23:39 UT, in non-photometric but very good seeing (0.6 arcsec) conditions. The asteroid moves in the same direction and at the same rate as the comet. In adition, the P/2010 A2 (LINEAR) image does not show any central condensation and looks like a "dust swarm". It is 4 arcmin long and only about 5 arcsec wide (177.000 and 3700 km respectively at the comet distance) with a PA=277 degrees. These observations suggest a connection between the asteroid and the dust swarm. A short lived event, such as a collision, may have produced the observed dust ejecta.". Next night, Jan. 16, the object was observed with the 10.4m GTC telescope and we made the following report "J. Licandro (Instituto de Astrofísica de Canarias, IAC, Spain), A. Cabrera-Lavers and G. Gómez (IAC & GTC Project Office, Spain) confirms the detection of an object, probably an asteroid, abut 2 arcsec to the East of P/2010 A2 (LINEAR), reported on Jan. 15 by Licandro et al. , on a series of 30s images obtained with the OSIRIS instrument on the 10.4m Gran Telescopio Canarias (GTC) at the "Roque de los Muchachos" Observatory (La Palma, Canary Islands, Spain), on Jan 16, starting 1:41 and ending 3:11 UT. A total of 54 images 30s exp. time each were obtained, 24 with the r, 18 with the i and 12 with the g sloan filters respectively. The object is visible in all images."

Following a suggestion by myself, Darryl Sergison imaged the comet with the 2.0-m Faulkes Telescope. Richard Miles reported:

A few images were taken of P/2010 A2 by Darryl Sergison using the 2.0-m Faulkes Telescope North on January 15 and these showed no evidence of condensations within the elongated coma however the seeing was not particularly good at the time. Another attempt stacking a dozen or so images when subarcsecond seeing is present will be necessary.

David Jewitt et al have a paper on the object, which is to appear in the Astronomical Journal. They conclude that it was an asteroid, which suffered a collision, and that such events should be relatively common, though generally below the detetection threshold of surveys such as LINEAR.

On 2013 June 3 the WIYN Observatory put out a press release describing how they had observed a tail of at least 15' using their new One Degree Imager (which currently does 30').  This apparent length corresponds to a real length of about 1 million km.

Brian Marsden noted on MPEC 2010-F69 [2010 March 23] that further [astrometric] observations of this comet were desirable.

2010 A2 (P/LINEAR) was recovered as an apparently asteroidal object via CCD images taken by Y. Kim with the 8.1-m "Gemini North" telescope at Mauna Kea on 2017 January 26.43. The indicated correction to the prediction by S. Nakano in the ICQ's 2017 Comet Handbook is Delta(T) = +0.16 day. [CBET 4405, MPEC 2017-M38, 2017 June 21]

K. J. Lawrence, Jet Propulsion Laboratory, reports the NEAT discovery of a comet on images taken with the Haleakala telescope, the object described as having a coma of diameter about 25", with elongated images but no obvious tail. The comet was also observed earlier on the same night (with prediscovery observations on Sept. 21) by the LINEAR team, which made no comment on the object's appearance; both "discovery" observations are tabulated below. Following posting on "The NEO Confirmation Page", numerous observers have reported on the object's cometary appearance on CCD images obtained during Oct. 5.9-6.6 UT, including M. Tichy (Klet), P. Birtwhistle (Great Shefford, U.K.), C. Jacques and E. Pimentel (Belo Horizonte, Brazil), D. T. Durig and G. A. T. Morris (Sewanee, TN), J. E. McGaha (Tucson, AZ), G. R. Jones (Tucson, AZ), and D. Higgins (Canberra, Australia). The general consensus is that there is a diffuse coma of diameter about 16"-30" and a faint, broad, fan- shaped tail about 1' wide and 4'-5' long in p.a. approximately 240-280 deg. P. Kusnirak (Ondrejov) reports the fan tail in p.a. about 290 deg and another tail about 4' long in p.a. about 240 deg. [IAUC 8416, 2004 October 6]

2004 T1 (P/LINEAR-NEAT) was recovered with the 1.0m reflector at the European Space Agency's Optical Ground Station at Tenerife on 2017 June 21.17. The indicated correction to the prediction by B. G. Marsden on MPC 89018 is Delta(T) = -0.57 day. The 2011 return was missed because the comet was in conjunction with the sun while near perihelion. [CBET 4406, MPEC 2017-M40, 2017 June 22]

Brian Marsden noted on MPEC 2010-H19 [2010 April 19] that further [astrometric] observations of this comet are very desirable.

PanSTARRS discovered a 21st magnitude comet on 2017 July 30.54, which appeared on the PCCP as P10Cawe, but was soon linked to 2010 D1 (P/WISE). The indicated correction to the prediction by Gareth Williams on MPC 89019 was Delta(T) = -1.85 days [CBET 4416, MPEC 2017-P09, 2017 August 3]

PanSTARRS recovered 2008 T4 with the 1.8m Ritchey-Chretien on August 18.49. There were also pre-recovery images from July 25. The indicated correction to the prediction by S. Nakano in the ICQ's 2017 Comet Handbook was Delta(T) = -0.67 day [CBET 4421, MPEC 2017-Q47, 2017 August 22/19]

On 2013 January 26 Rob Matson found images of a comet in frames taken by NEAT with the Palomar 1.2m Schmidt on 2001 December 9. This was linked to 2003 BM80, discovered by LONEOS at the Anderson Mesa station on 2003 January 31 and to 2012 T1.

Although the comet was numbered, the MPC list as recently as 2017 July 10 did not give it a name.  It was recovered on 2017 July 1.37 with the Gemini South 8.1m reflector.  This time it was given the PanSTARRS name and the designation 2017 O3, though not linked to the originally numbered comet. [MPEC 2017-Q115, 2017 August 25] The object previously linked with the comet is now considered to be a Main-belt asteroid and has been numbered as (323137) with an additional identity with 2003 FV112. This object retains the identity 282P. The 2001 NEAT object is linked to comet 358P.

The ESA Optical Ground Station at Tenerife recovered 2010 P4 with the 1.0m telescope on 2017 September 20.10. [CBET 4429, MPEC 2017-S90, 2017 September 20]

Gareth Williams reported on MPEC 2017-N50 [2017 July 3]:

G. J. Leonard, using the MLS 1.5-m reflector, reported a comet candidate, described as having a coma of 7"-8" diameter and a broad ~15"-long tail in P.A. ~260 deg. This object was linked by MPC automated routines with the numbered Hilda minor planet (457175). Follow-up observations by D. C. Fuls with the MLS 1.0-m reflector confirm the cometary nature: very bright coma at least 8" diameter, with a very broad 12"-long tail in P.A. 265 deg. Additional follow-up observation by Leonard show as 10" coma and a broad, diffuse 15"-long tail in P.A. ~260 deg.

Further observations of this object are encouraged to clarify the nature of this cometary activity.

The comet was perturbed from a Centaur type orbit by a close (0.05 au) encounter with Jupiter in 1710. The orbit was further perturbed in 2011 September, and the first perihelion since then was in 2016.

Paplo Ruiz recovered 2011 VJ5 (P/Lemmon) on November 19.13 using a 1.0-m f/4.4 reflector at the European Space Agency's Optical Ground Station, Tenerife, Spain. It was confirmed the following night, and then additional images from October and earlier in November were found by Gareth Williams. The indicated correction to the prediction by S. Nakano is Delta(T) = +1.04 day. [CBET 4455, MPEC 2017-W73, 2017 November 19/20].

2 CCD and visual observations received at the 2013 return suggest a preliminary aperture corrected light curve of m = 15.2 + 5 log d + [10] log r

Erwin Schwab reported the recovery of 2013 CU129 to the Central Bureau in remotely obtained images that he had taken with the 0.8m Schmidt at Calar Alto, Spain, on January 16.92. In the meantime Gareth Williams of the Minor Planet Centre had identified the comet in incidental astrometry from Mt Lemmon on January 12.38. As is becomming commonplace, two CBETs were required to correctly announce the recovery. [CBET 4474, 4475, MPEC 2018-B14, 2018 January 17] The indicated correction to the prediction by S. Nakano in the ICQ's 2018 Comet Handbook is Delta(T) = +0.02 day.

2005 JN was recovered with the 1.0m f/4.4 reflector at the ESA Optical Ground Station at Tenerife on 2018 March 17.18. It was 20th magnitude.

Cometary activity was finally confirmed in 2013, when it was observed from August to October. [MPEC 2013-U85, 2013 October 30]. The comet has a period of 6.6 years.

Erwin Schwab recovered the comet during remote observations with the Calar Alto 0.8m Schmidt on 2018 April 17.01. No tail or coma was detected in total exposures of 600s.

The comet was recovered in images taken at the European Space Agency's Optical Ground Station at Teneriffe with the 1.0m reflector on June 13.19. It was 19th magnitude. The indicated correction to the prediction by S. Nakano in the ICQ's 2018 Comet Handbook is Delta(T) = -0.07 day. [CBET 4526, MPEC 2018-L76, 2018 June 14]

Erwin Schwab reported the recovery of 2010 A1 in images taken with the 1.0m reflector at the European Space Agency's Optical Ground Station at Teneriffe on August 10.18. [CBET 4538, MPEC 2018-P80, 2018 August 13] The MPEC says "The 2018 prediction by B. G. Marsden on MPC 94681 required a correction in T of +0.39 days." A better phrasing might be "The prediction for the 2018 return by B. G. Marsden on MPC 94681 required a correction in T of +0.39 days."

Erwin Schwab reported the recovery of 2001 T3 in images taken with the 1.0m reflector at the European Space Agency's Optical Ground Station at Teneriffe on August 10.20. [CBET 4539, MPEC 2018-P81, 2018 August 13] The 2018 prediction by the Gareth Williams on MPC 94679 required a correction in T of -1.16 days.

Erwin Schwab reported his recovery of 2001 R6 in images taken with the 1.0m reflector at the European Space Agency's Optical Ground Station at Teneriffe on September 7.09. The comet was not recovered at the 2010 return. The correction to T compared to the 2013 MPEC prediction is +0.36 days. [CBET 4552, MPEC 2018-R59, 2018 September 8]

Brian Marsden noted on MPEC 2008-Q07 [2008 August 18] that the orbit indicates a very close approach to Jupiter (to 0.1 au) in 2003 and that the previous perihelion distance was around 5.8 au.

Gareth Williams recovered 2008 O2 in astrometric data submitted by PanSTARRS (PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on August 8.50) and the Gaia-GBOT team (images taken with the 2.6m Ritchey-Chretien at Cerro Paranal on September 6.13). The comet was apparently stellar in appearance. [CBET 4554, MPEC 2018-S01, 2018 September 16] The prediction for the return by Gareth Williams on MPC 94681 required a correction in T of -0.52 days.

Jean-Francois Soulier (0.3m Newtonian f/4 reflector at Maisoncelles, September 9.03) and Krisztian Sarneczky (0.6m Schmidt at the University of Szeged, Piszkesteto Station (Konkoly), September 14.11) independently recovered 2011 W2. The prediction for the return by Gareth Williams on MPC 102105 required a correction to T of -0.43 days. [CBET 455x, MPEC 2018-S03, 2018 September 16]

Krisztian Sarneczky and Robert Szakats (0.6m Schmidt at the University of Szeged, Piszkesteto Station (Konkoly)) recovered 2007 V1 on September 18.00. The prediction for the return by Gareth Williams on MPC 102104 required a correction to T of -1.17 days. [CBET 4558, MPEC 2018-S31, 2018 September 18]

Krisztian Sarneczky (0.6m Schmidt and 1.02m Ritchey-Chretien at the University of Szeged, Piszkesteto Station (Konkoly)) recovered 2006 D1 on 2018 October 5.10. The prediction for the return by Gareth Williams on MPC 94682 required a correction to T of -0.22 days. [CBET 4560, MPEC 2018-T62, 2018 October 6]

Erwin Schwab reported the recovery of 2005 GF8 in images taken with the 1.0m reflector at the European Space Agency's Optical Ground Station at Teneriffe on 2018 December 4.25. The correction to the prediction by B. G. Marsden on MPC 54823 is delta-T = -1.4 days. [CBET 4581, MPEC 2018-X49, 2018 December 6]

J. V. Scotti, Lunar and Planetary Laboratory, University of Arizona, reports the discovery of a 20th mag comet on CCD images taken with the Spacewatch 0.9-m f/3 reflector at Kitt Peak on June 4.21, showing a coma of diameter 6" and a faint tail about 0'.62 long in p.a. 273 deg. Images taken by A. S. Descour on June 5.3 with the 1.8-m f/2.7 Spacewatch reflector also show a tail, and June 7.2 images by Scotti with the larger instrument show the tail 0'.30 long in p.a. 273 deg. [IAUC 8145, 2003 June 7]

Clearly diffuse NEAT images of this comet, taken with the Palomar 1.2-m Schmidt telescope on three nights in 2002 April, were identified and measured by M. Meyer. Additional astrometry and the orbital elements (MPEC 2003-M21) confirm the suspicion (cf. IAUC 8145) that this is a short-period comet. [IAUC 8153, 2003 June 19]

Erwin Schwab reported his recovery of 2003 L1 in images taken with the 1.0m reflector at the European Space Agency's Optical Ground Station at Teneriffe on 2019 March 9.11. The correction to T compared to the 2017 prediction on MPC 105247 is -0.39 days. [CBET 4612, MPEC 2019-E80, 2019 March 10]

Erwin Schwab reported his recovery of 2005 Y2 in images taken with the 1.0m reflector at the European Space Agency's Optical Ground Station at Teneriffe on 2019 March 10.14. The correction to T compared to the 2011 prediction on MPC 75706 is +0.04 days. [CBET 4613, MPEC 2019-F27, 2019 March 18]

This comet, missed at its 2012 apparition, was recovered by Gareth Williams in incidental astrometry reported by the Mount Lemmon Survey from February 28.38, which was then linked to a single-night detection on the NEOCP. R. Weryk (F51) also suggested the linkage when he reported that the same NEOCP object had a FWHM of ~1".8 (compared to 1".15 +/- 0".04 for nearby stars) and a ~4" tail to the east. The indicated delta-T correction to the prediction, by B. G. Marsden, on MPC 56954 is -1.29 days (in 2012, the correction was -0.61 days). [CBET 4616, MPEC 2019-G21, 2019 April 3].

The IAU Committee on Small Bodies Nomenclature gave to comet P/2000 S4 (cf. IAUC 7502) the name LINEAR-Spacewatch. [IAUC 7553, 2000 December 31]

Gareth Williams found images of 2000 S4 (P/LINEAR-Spacewatch) in incidental astrometry submitted by PanSTARRS and the Mt Lemmon Survey taken on 2019 May 29.57 (PanSTARRS) and 2019 June 1.44 (Mt Lemmon). The indicated delta-T correction to the prediction on MPC 102107 is +0.25 days. [CBET 4633, MPEC 2019-L11, 2019 June 2/3]

Gareth Williams found images of the comet in incidental astrometry submitted by PanSTARRS taken on 2019 May 31.45. Erwin Schwab also reported the recovery in images taken with the 0.8m Schmidt at Calar Alto, Spain on May 29.09. The indicated delta-T correction to the prediction on MPC 75514 is -0.08 days. [CBET 4635, MPEC 2019-L42, 2019 June 3/4]

Krisztian Sarneczky recovered 2006 S1 with the 0.6m Schmidt at the University of Szeged, Piszkesteto Station (Konkoly) on June 25.90. It was 20th magnitude. The prediction for the return by Brian Marsden on MPC 102108 required a correction to T of +0.71 days, which corresponds to about half a degree from the expected position. [MPEC 2019-N62, 2019 July 5, CBET 4649, July 6]. The MPEC did not give a designation, but this was given on the CBET. The comet was missed at the 2013 return.

Hirohisa Sato recovered 2014 U2 in images taken with an iTelescope 0.51-m f/6.8 astrograph at Siding Spring, NSW on July 27.81. The indicated delta-T correction to the prediction on MPC 102108 is -0.02 days. [CBET 4654, MPEC 2019-O84, 2019 July 28]

Krisztian Sarneczky recovered 2010 U2 with the 0.6m Schmidt at the University of Szeged, Piszkesteto Station (Konkoly) on August 2.05, with confirming images on the 7th. It was 21st magnitude. The indicated delta-T correcton to the prediction, by Gareth Williams, on MPC 102107 is -0.47 days. [MPEC 2019-P61, CBET 46xx, 2019 August 9].

The comet was finally numbered following recovery in 2019 September by PanSTARRS, with further images then found from 2013. The orbit on NK 2184, from the 2011-2012 observations alone, required a Delta(T) correction of -7.2 days. It makes occasional approaches to Jupiter, most recently to 0.81 au in 2010 March. It will pass 0.63 au from the planet in 2033.  No designations seem to have been made for the 2004 or 2019 returns and the CBET does not give the number [CBET 4693, 2019 November 5].

Gennady Borisov recovered 2008 Y1 in images taken with the MARGO 0.65-m f/1.5 astrograph at Nauchnij, Crimea on September 2.01. It was placed on the PCCP as gb00239. The indicated delta-T correction to the prediction, by Brian G. Marsden on MPC 102107, is -4.38 days. [CBET 4663, MPEC 2019-R83, 2019 September 9]

Hirohisa Sato recovered 2007 T4 in images taken with an iTelescope 0.43-m f/6.8 astrograph near Mayhill, New Mexico on September 5.48. The indicated delta-T correction to the prediction on NK 1629 is -0.02 days. [CBET 4662, 2019 September 8, CBET 4664, MPEC 2019-R84, 2019 September 9]

Donna Burton is being trained as a new observer for the Siding Spring Survey, initially as a replacement for Gordon Garradd who is on 2 months sick leave following a cycling accident. Sep 01 was Donna's first time alone at the telescope. When she found 6R6F4D3 she phoned me so I went to the telescope to check on the detection and show how to schedule follow up. The first follow up was involved with a star, but the next was good. All the data was submitted. It was only with a second call later in the night with her detection of 6R6F50C that I noticed that some of the 6R6F4D3 images looked a bit soft and checking back through the other images confirmed that all images had the same appearance of diffuseness. This was confirmed for certain on images taken the following night. Thus Donna discovered the object and I noted that it was a comet, hence "Siding Spring".

It is still possible that the orbital period is somewhat longer than the best-fit value of 16 years (which would be the shortest for a comet having a retrograde orbit).

2006 R1 was recovered independently by Gareth Williams and R. Weryk in images from Pan-STARRS 1 taken on September 25.53. The indicated delta-T correction to the prediction, by Gareth Williams, on MPC 105244, is -6.6 days, with a period of 13.4 years.

A comet discovered in images taken with the 0.5m Schmidt at Haleakala on 2019 October 21.25 by the ATLAS (Asteroid Terrestrial-impact Last Alert System) team was identified as a return of 2006 W1 by the MPC and Hirohisa Sato. The indicated delta-T correction to the prediction on  NK 3401 is -9.5 days.  The comet passed 1.4 au from Saturn in 2010 July.  [CBET 4685, MPEC 2019-U163, 2019 October 25] The comet is at perihelion at 1.7 au in 2020 March.

The initial orbit suggested that it would reach perihelion at 1.9 au in 2007 May, however further observations however showed that it was in a periodic orbit [as first suggested by Hirohisa Sato], period 10 years, with perihelion at 4.1 au in February 2008. The comet had a very close encounter with Jupiter on 2003 January 4, when it passed 0.0096 au from the planet. It will make another close approach in 2073.

BAA Member Kevin Hills recovered 2006 F1 (P/Kowalski) on October 22.01 in images taken with his 0.5-m f/2.9 astrograph at Tacande Observatory, La Palma. It was also recovered by PanSTARRS on October 25.35, with both sites reporting additional pre-recovery images. The indicated delta-T correction to the prediction on MPC 94677 was -0.06 days. [CBET 4686, MPEC 2019-U193, 2019 October 28]

An apparently asteroidal object discovered by LINEAR on 2004 November 22.32, and published as 2004 WR_9 on MPO 120656, has been found to show cometary appearance. P. Birtwhistle, Great Shefford, U.K., reports that CCD images taken on Dec. 7.0 UT with a 0.30-m f/6.3 reflector show the object as having a tail 20" long in p.a. 235 deg and a very concentrated coma with a diameter of 9", while on images from Dec. 3.0, there had been a suggestion of a 10" tail in p.a. 250 deg. C. Hergenrother reports that R-band images taken with the Catalina 1.54-m reflector on Dec. 8.45 show a highly condensed coma 11" in diameter and a faint tail > 25" long in p.a. 235 deg. [IAUC 8448, 2004 December 8]

Krisztian Sarneczky recovered 2004 WR9 with the 0.6m Schmidt at the University of Szeged, Piszkesteto Station (Konkoly) on October 26.96, with confirming images on the 27th. It was 19th magnitude. The indicated delta-T correcton to the prediction, by Gareth Williams, on MPC 105245 is -0.75 days. [MPEC 2019-U245, CBET 4687, 2019 October 28].

A 21st magnitude comet was reported by Scott Sheppard on 2019 November 8 in images taken with the 4.0m reflector at the Cerro Tololo observatory on 2019 September 24.29 and 26.23. The MPC then identified it as a recovery of 2009 SK280 and found additional PanSTARRS and Mt Lemmon images from 2019 October. The indicated delta-T correction to the prediction on MPC 102108 by Gareth Williams is +0.87 days. Syuichi Nakano notes that prior to a close approach of the comet to Jupiter on 1994 May 2 at a distance of 0.13 au, the comet had a slightly closer perihelion and slightly more eccentric orbit. [CBET 4697, MPEC 2019-V147, 2019 November 12]

The comet 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 4758, 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.

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]

For some reason the current MPC lists do not give it a name.

Hirohisa Sato recovered the comet 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]

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.

The comet passed 0.55 au from Jupiter in 1984 June. It will pass 0.4 au from the Earth in 2020 December, when it could reach 14th magnitude.

Syuichi Nakano noticed that recovery observations of 2013 O2 had been published in recent MPECs listing observations of comets (2020-P19, Q175 and R04). The earliest observations (2020 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]

This is another out of order numbering, which should have been 404 if numbered sequentially.

Published by Jonathan Shanklin. Jon Shanklin - jds@ast.cam.ac.uk