Comet Section

September 2, 2023 – ALPO Comet News for September 2023

August was a busy month for comet watchers. In addition to observing 12P/Pons-Brooks in outburst and 9th magnitude C/2023 E1 (ATLAS) and C/2020 V2 (ZTF), a new bright amateur comet was discovered around mid-month. C/2023 P1 (Nishimura) is now 6th magnitude and should brighten to 4th-5th magnitude before being lost in the glare of the Sun. September will also see returning periodic comets 2P/Encke and 103P/Hartley brighten to 9th and 7th magnitude by the end of the month, respectively.

Also, observable in September are C/2020 V2 (ZTF) at 9th magnitude, 12P/Pons-Brooks and C/2017 K2 (PANSTARRS) at 11th mag, C/2021 S3 (PANSTARRS) brightening from 12th to 11th magnitude, C/2021 T4 (Lemmon) fading from 10th to 11th magnitude, and C/2023 E1 (ATLAS) fading from 10th to 12th magnitude.

Last month the ALPO Comets Section received 277 observations of comets C/2023 P1 (Nishimura), C/2023 E1 (ATLAS), C/2023 A3 (Tsuchishan-ATLAS), C/2022 W3 (Leonard), C/2022 JK5 (PANSTARRS), C/2022 A2 (PANSTARRS), C/2021 X1 (Maury-Attard), C/2021 T4 (Lemmon), C/2021 S3 (PANSTARRS), C/2020 V2 (ZTF), C/2020 O2 (Amaral), C/2020 K1 (PANSTARRS), C/2019 T4 (ATLAS), C/2017 K2 (PANSTARRS), P/2014 W1 (PANSTARRS), 364P/PANSTARRS, 347P/PANSTARRS, 326P/Hill, 310P/Hill, 276P/Vorobjov, 242P/Spahr, 237P/LINEAR, 126P/IRAS, 103P/Hartley, 80P/Peters-Hartley, 41P/Tuttle-Giacobini-Kresak, 32P/Comas Sola, 12P/Pons-Brooks, and 2P/Encke. A big thanks to our August contributors: Dan Bartlett, Michel Besson, Michel Deconinck, J. J. Gonzalez, Jose Guilherme de Souza Aguiar, Andrew Hampton, Christian Harder, Scott Harrington, Carl Hergenrother, Eliot Herman, Michael Jäger, John Maikner, Martin Mobberley, Charles Morris, Gary T. Nowak, Mike Olason, Uwe Pilz, Ludovic Prebet, Michael Rosolina, Greg Ruppel, Greg Shanos, Tenho Tuomi, and Chris Wyatt.

The monthly ALPO Comet News PDF can be found here. A shorter version of this report is posted on a dedicated Cloudy Nights forum. All are encouraged to join the discussion over at Cloudy Nights.

August 3, 2023 – ALPO Comet News for August 2023

This month we welcome two returning periodic comets breaking the 12th magnitude barrier. In April 2024, Halley-type comet 12P/Pons-Brooks will make its first perihelion passage since 1954. On July 20th, it experienced a 4- to 5-magnitude outburst and is now an 11th-magnitude object in the evening sky. Due to peak at 7th magnitude this October, 103P/Hartley is returning for the second time since its superb return in 2010. By the end of this month, 103P should brighten to magnitude 9.5 in the morning sky.

Also visible this month are 8th magnitude C/2021 T4 (Lemmon), 9th magnitude C/2020 V2 (ZTF) and C/2023 E1 (ATLAS), and 11th magnitude C/2017 K2 (PANSTARRS).

Last month the ALPO Comets Section received 180 observations of comets C/2023 E1 (ATLAS), C/2023 A3 (Tsuchishan-ATLAS), C/2022 W3 (Leonard), C/2022 E3 (ATLAS), C/2022 A2 (PANSTARRS), C/2021 T4 (Lemmon), C/2020 V2 (ZTF), C/2020 K1 (PANSTARRS), C/2019 U5 (PANSTARRS), C/2019 T4 (ATLAS), C/2019 L3 (ATLAS), 237P/LINEAR, 126P/IRAS, 103P/Hartley, 80P/Peters-Hartley, 32P/Comas Sola, 12P/Pons-Brooks, and 2P/Encke. A big thanks to our July contributors: Dan Bartlett, J. J. Gonzalez, Jose Guilherme de Souza Aguiar, Christian Harder, Carl Hergenrother, Eliot Herman, John Maikner, Martin Mobberley, Charles Morris, Gary T. Nowak, Uwe Pilz, Michael Rosolina, Greg Shanos, Tenho Tuomi, and Chris Wyatt.

The monthly ALPO Comet News PDF can be found here. A shorter version of this report is posted on a dedicated Cloudy Nights forum. All are encouraged to join the discussion over at Cloudy Nights.

July 3, 2023 – ALPO Comet News for July 2023

July will be a nice month for comet watchers. While there are no “bright” comets, three comets should make nice targets for binoculars or small telescopes. The brightest comet of the month, 7th magnitude C/2021 T4 (Lemmon), will be well placed for southern hemisphere observers as it races from the morning into the evening sky. Northern observers will be able to observe it early in the month though a bright Moon and a decreasing elevation will make it a bit challenging. Northern observers will have 9th magnitude C/2023 E1 (ATLAS) all to themselves as it moves through the northern circumpolar sky. Both hemispheres can observe 9-10th magnitude C/2020 V2 (ZTF) in the morning sky. Imagers are asked to watch one of next year’s potential bright objects, C/2023 A3 (Tsuchinshan-ATLAS), at 16th magnitude in the evening sky.

Last month the ALPO Comets Section received 99 magnitude estimates, images, and sketches of comets C/2023 E1 (ATLAS), C/2023 A3 (Tsuchishan-ATLAS), C/2022 E3 (ATLAS), C/2022 A2 (PANSTARRS), C/2021 T4 (Lemmon), C/2021 S3 (PANSTARRS), C/2020 V2 (ZTF), C/2020 K1 (PANSTARRS), C/2019 U5 (PANSTARRS), C/2019 T4 (ATLAS), C/2019 L3 (ATLAS), C/2017 K2 (PANSTARRS), 364P/PANSTARRS, 276P/Vorobjov, 237P/LINEAR, 126P/IRAS, 77P/Longmore, 71P/Clark, and 12P/Pons-Brooks. A big thanks to our June contributors: J. J. Gonzalez, Jose Guilherme de Souza Aguiar, Christian Harder, Carl Hergenrother, Eliot Herman, John Maikner, Michael Rosolina, and Chris Wyatt.

The monthly ALPO Comet News PDF can be found here. A shorter version of this report is posted on a dedicated Cloudy Nights forum. All are encouraged to join the discussion over at Cloudy Nights.

June 4, 2023 – ALPO Comet News for June 2023

May was a quiet month for comet watchers as the sky was lacking in bright or even semi-bright comets. June should bring some improvement. C/2020 V2 (ZTF), which has been around magnitude 9.0 to 9.5 for most of the year, is again visible after passing solar conjunction. C/2021 T4 (Lemmon) and C/2023 E1 (ATLAS) are expected to start the month at 10th magnitude and reach magnitude 9 by the end of the month. C/2021 T4 (Lemmon) is primarily an object for southern hemisphere observers, while C/2023 E1 (ATLAS) is a northern-only object.

Last month the ALPO Comets Section received 60 magnitude estimates and images/sketches of comets C/2023 E1 (ATLAS), C/2023 A3 (Tsuchishan-ATLAS), C/2021 T4 (Lemmon), C/2020 K1 (PANSTARRS), C/2019 U5 (PANSTARRS), C/2019 T4 (ATLAS), C/2019 L3 (ATLAS), C/2017 K2 (PANSTARRS), 364P/PANSTARRS, 263P/Gibbs, 237P/LINEAR, 199P/Shoemaker, 133P/Elst-Pizarro, 130P/McNaught-Hughes, 99P/Kowal, 96P/Machholz, 81P/Wild, 219P/LINEAR, 103P/Hartley, 80P/Peters-Hartley, 77P/Longmore, 71P/Clark, and 12P/Pons-Brooks. A big thanks to our May contributors: J. J. Gonzalez, Jose Guilherme de Souza Aguiar, Carl Hergenrother, John Maikner, and Chris Wyatt.

The monthly ALPO Comet News PDF can be found here. A shorter version of this report is posted on a dedicated Cloudy Nights forum. All are encouraged to join the discussion over at Cloudy Nights.

May 1, 2023 – ALPO Comet News for May 2023

We are in a bit of a bright comet drought at the moment. Most of the brighter comets of early 2023 have now faded with only one still brighter than magnitude 10, C/2020 V2 (ZTF), which is too close to the Sun in May to observe.

There are several fainter comets visible between magnitude 10 and 12 this month. Two new comets to this newsletter are breaking the magnitude 12 barrier on their way to becoming even brighter in the months ahead. Though C/2021 T4 has been unobservable for much of the last 3 months, its brightening trend up till January suggested a peak brightness around magnitude 8.0 in July. Newly discovered C/2023 E1 (ATLAS) is on an 85-year orbit and has rapidly brightened to around 12-13th magnitude. It should peak at magnitude 10 or even brighter in July and August.

Last month the ALPO Comets Section received 108 magnitude estimates and 16 images/sketches of comets C/2023 E1 (ATLAS), P/2023 B1 (PANSTARRS), C/2023 A3 (Tsuchishan-ATLAS), C/2022 E3 (ZTF), C/2022 A2 (PANSTARRS), C/2020 V2 (ZTF), C/2020 K1 (PANSTARRS), C/2019 U5 (PANSTARRS), C/2019 T4 (ATLAS), C/2019 L3 (ATLAS), C/2017 K2 (PANSTARRS), P/2010 WJ5 (Catalina), P/2010 VH95 (Catalina), 452P/Shappard-Jewitt, 393P/Spacewatch-Hill, 364P/PANSTARRS, 299P/Catalina-PANSTARRS, 263P/Gibbs, 237P/LINEAR, 199P/Shoemaker, 133P/Elst-Pizarro, 130P/McNaught-Hughes, 99P/Kowal, 96P/Machholz, 81P/Wild, 77P/Longmore, 71P/Clark, 67P/Churyumov-Gerasimenko, 19P/Borrelly, and 12P/Pons-Brooks. A big thanks to our March contributors: Dan Bartlett, Denis Buczynski, J. J. Gonzalez, Jose Guilherme de Souza Aguiar, Christian Harder, Carl Hergenrother, John Maikner, Martin Mobberley, Mike Olason, Uwe Pilz, Efrain Morales Rivera, Gregg Ruppel, Greg T. Shanos, and Chris Wyatt.

The monthly ALPO Comet News PDF can be found here. A shorter version of this report is posted on a dedicated Cloudy Nights forum. All are encouraged to join the discussion over at Cloudy Nights.

April 4, 2023 – ALPO Comet News for April 2023

The brightest comets in April are all expected to be around 9th magnitude, so not very bright. The lack of any bright comets is balanced by a number of interesting objects between magnitude 10 and 12. Two high numbered short-period comets, 237P/LINEAR and 364P/PANSTARRS, are making their best returns in years and should peak around 10-11th magnitude. Both comets have relatively large nuclei and are only active in the months around perihelion.

Of the 9th magnitude comets, there are three and they are all of the long-period variety. C/2017 K2 (PANSTARRS) is still a southern hemisphere only object and should become fainter than magnitude 10.0 for the first time in a year. C/2022 A2 (PANSTARRS) is a northern hemisphere only comet but will also become fainter than magnitude 10.0 early this month. The other 9th magnitude comet is C/2020 V2 (ZTF). With an upcoming solar conjunction in early May, everyone will have lost V2 to the glare of the Sun by mid-April. We’ll be able to pick V2 up again in June or July when it will still be a mid-9th magnitude object.

Last month the ALPO Comets Section received 101 magnitude estimates and 49 images/sketches of comets C/2022 E3 (ZTF), C/2022 A2 (PANSTARRS), C/2021 Y1 (ATLAS), C/2021 S3 (PANSTARRS), C/2020 V2 (ZTF), C/2020 K1 (PANSTARRS), C/2019 U5 (PANSTARRS), C/2019 T4 (ATLAS), C/2019 L3 (ATLAS), C/2019 K7 (Smith), C/2017 K2 (PANSTARRS), 452P/Sheppard-Jewitt, 451P/Christensen, 423P/Lemmon, 364P/PANSTARRS, 263P/Gibbs, 256P/LINEAR, 237P/LINEAR, 211P/Hill, 169P/NEAT, 129P/Shoemaker-Levy, 96P/Machholz, 89P/Russell, 81P/Wild, 77P/Longmore, 48P/Johnson, 19P/Borrelly, 12P/Pons-Brooks, and 4P/Faye. A big thanks to our March contributors: Dan Bartlett, Denis Buczynski, J. J. Gonzalez, Jose Guilherme de Souza Aguiar, Christian Harder, Carl Hergenrother, John Maikner, Martin Mobberley, Mike Olason, Uwe Pilz, Efrain Morales Rivera, Gregg Ruppel, Greg T. Shanos, and Chris Wyatt.

The monthly ALPO Comet News PDF can be found here. A shorter version of this report is posted on a dedicated Cloudy Nights forum. All are encouraged to join the discussion over at Cloudy Nights.

March 4, 2023 – ALPO Comet News for March 2023

After starting 2023 off with a bang, C/2022 E3 (ZTF) is still the brightest comet in the sky but fading fast this month from around magnitude 8 to 10. Southern observers will still be able to observe last summer’s brightest comet, C/2017 K2 (PANSTARRS), which will fade from 8th to 9th magnitude. Up north, northerners have 9th magnitude comets C/2020 V2 (ZTF) and C/2022 A2 (PANSTARRS) to themselves.

Rounding out the comets with those expected to be between magnitude 10 and 12 are 81P/Wild, C/2019 L3 (ATLAS), and C/2019 U5 (PANSTARRS).

A recently announced new discovery, C/2023 A3 (Tsuchishan-ATLAS), looks like a promising comet for 2024. While we still have months to watch Tsuchishan-ATLAS develop, it may become a naked eye object in September and October of 2024 though it will be located close to the Sun at its best.

Last month the ALPO Comets Section received 112 magnitude estimates and 91 images/sketches of comets C/2022 U2 (ATLAS), C/2022 P1 (NEOWISE), C/2022 E3 (ZTF), C/2022 A2 (PANSTARRS), C/2021 Y1 (ATLAS), C/2021 S3 (PANSTARRS), C/2020 V2 (ZTF), C/2020 S4 (PANSTARRS), C/2019 U5 (PANSTARRS), C/2019 T4 (ATLAS), C/2019 L3 (ATLAS), C/2017 K2 (PANSTARRS), 452P/Sheppard-Jewitt, 364P/PANSTARRS, 362P/(457175) 2008 GO98, 272P/NEAT, 230P/LINEAR, 179P/Jedicke, 118P/Shoemaker-Levy, 113P/Spitaler, 96P/Machholz, 81P/Wild, 29P/Schwassmann-Wachmann, and 12P/Pons-Brooks. A big thanks to our recent contributors: Salvador Aguirre, Michael Amato, Dan Bartlett, Michel Besson, Todd Bossaller, Denis Buczynski, J. J. Gonzalez, Jose Guilherme de Souza Aguiar, Christian Harder, Scott Harrington, Carl Hergenrother, Eliot Herman, Rik Hill, Michael Jäger, John Maikner, Martin Mobberley, Charles Morris, Mike Olason, Phill Parslow, Ludovic Perbet, Clement Planchon, Olivier Planchon, Uwe Pilz, Allan Rahill, Efrain Morales Rivera, Michael Rosolina, Gregg Ruppel, Anaël Semiat, Richard Schmude, Jr., Chris Schur, Greg T. Shanos, Willian Souza, and Chris Wyatt.

The monthly ALPO Comet News PDF can be found here. A shorter version of this report is posted on a dedicated Cloudy Nights forum. All are encouraged to join the discussion over at Cloudy Nights.

February 4, 2023 – ALPO Comet News for February 2023

C/2022 E3 (ZTF) is at its best as February starts. Several observers have made naked eye detections during the last week of January. At between magnitude 4.6 and 5.1, ZTF is a very easy binocular object but will require dark skies to be seen with the naked eye. With a close approach to Earth at 0.29 au on February 1, the comet should fade rather rapidly in February and may be as faint as magnitude 8 by the end of the month. Though fading, its southern motion will allow southern mid-latitude observers a chance to see it early in the month.

C/2022 E3 (ZTF) is not the only reasonably bright comet. In the southern hemisphere, C/2017 K2 (PANSTARRS) is at 8th magnitude. Northern observers will also be able to follow 9th magnitude comets C/2020 V2 (ZTF), C/2022 A2 (PANSTARRS), and C/2022 U2 (ATLAS). While C/2020 V2 (ZTF) and C/2022 A2 (PANSTARRS) are limited to northern observers, C/2022 U2 (ATLAS) will be visible from the southern hemisphere as well.

Last month’s brightest comet wasn’t C/2022 E3 (ZTF) but rather 96P/Machholz at 0th to 2nd magnitude. Unfortunately, it was only visible through the eyes of the SOHO and STEREO-A spacecraft as it was only a few degrees from the Sun at its brightest in late January. Eagle eyed observers with a clear horizon may spot 96P later in the month low in the morning sky though it should have faded to 8-10th magnitude by then.

Last month the ALPO Comets Section received 83 magnitude estimates and 122 images/sketches of comets C/2022 U2 (ATLAS), C/2022 P1 (NEOWISE), C/2022 E3 (ZTF), C/2022 A2 (PANSTARRS), C/2021 Y1 (ATLAS), C/2021 X1 (Maury-Attard), C/2021 QM45 (PANSTARRS), C/2020 V2 (ZTF), C/2020 S4 (PANSTARRS), C/2019 U5 (PANSTARRS), C/2019 L3 (ATLAS), C/2017 K2 (PANSTARRS), 96P/Machholz, and 29P/Schwassmann-Wachmann. A big thanks to our recent contributors: Michael Amato, Dan Bartlett, Michel Besson, Todd Bossaller, Denis Buczynski, J. J. Gonzalez, Jose Guilherme de Souza Aguiar, Christian Harder, Carl Hergenrother, Eliot Herman, Rik Hill, Michael Jäger, Martin Mobberley, Charles Morris, Mike Olason, Phill Parslow, Ludovic Perbet, Uwe Pilz, Allan Rahill, Efrain Morales Rivera, Gregg Ruppel, Anaël Semiat, Richard Schmude, Jr., Chris Schur, Greg T. Shanos, and Chris Wyatt.

The monthly ALPO Comet News PDF can be found here. A shorter version of this report is posted on a dedicated Cloudy Nights forum. All are encouraged to join the discussion over at Cloudy Nights.

January 3, 2023 – ALPO Comet News for January 2023

Happy New Year! Just like with 2022, 2023 starts out with a nice bright comet. C/2022 E3 (ZTF) begins the year at around magnitude 7.5. With perihelion on January 12 and a close approach to Earth at 0.29 au on February 1, E3 could peak as bright as magnitude 4.7 by the end of the month. Not super bright, but a nice binocular object for all and a borderline naked eye object for those under dark skies. Though the comet will be too far north for most southern hemisphere observers, it will be a circumpolar object for northern hemisphere observers.

While C/2022 E3 will be the center of attention in January, it won’t be the only comet visible. C/2017 K2 (PANSTARRS) will be around 8th magnitude for southern observers, while northerners will also be able to follow a trio of 9th magnitude comets: C/2020 V2 (ZTF), C/2022 A2 (PANSTARRS), and C/2022 U2 (ATLAS). Those able to go a little fainter (to magnitude 12.0) can also observed 29P/Schwassmann-Wachmann, 81P/Wild, C/2019 L3 (ATLAS), C/2019 U5 (PANSTARRS), and C/2020 K1 (PANSTARRS).

Somewhat surprisingly, the brightest comet of the month will not be C/2022 E3 (ZTF) but rather 96P/Machholz at 2nd magnitude or perhaps even brighter. But no one on Earth will be able to see 96P at that brightness with their own eyes. Instead, we’ll be able to watch it through the eyes of the SOHO spacecraft as it will only be a few degrees from the Sun at its brightest in late January.

Last month the ALPO Comets Section received 101 magnitude estimates and 67 images/sketches of comets C/2022 U2 (ATLAS), C/2022 P1 (NEOWISE), C/2022 E3 (ZTF), C/2022 A2 (PANSTARRS), C/2021 Y1 (ATLAS), C/2021 X1 (Maury-Attard), C/2021 T4 (Lemmon), C/2020 Y2 (ATLAS), C/2020 V2 (ZTF), C/2019 U5 (PANSTARRS), C/2019 L3 (ATLAS), C/2017 K2 (PANSTARRS), 119P/Parker-Hartley, 118P/Shoemaker-Levy, 81P/Wild, 73P/Schwassmann-Wachmann, 29P/Schwassmann-Wachmann, and 22P/Kopff. A big thanks to our recent contributors: Dan Bartlett, Denis Buczynski, J. J. Gonzalez, Jose Guilherme de Souza Aguiar, Christian Harder, Carl Hergenrother, Eliot Herman, Michael Jager, Martin Mobberley, Uwe Pilz, Gregg Ruppel, and Chris Wyatt.

The monthly ALPO Comet News PDF can be found here. A shorter version of this report is posted on a dedicated Cloudy Nights forum. All are encouraged to join the discussion over at Cloudy Nights.

December 4, 2022 – ALPO Comet News for December 2022

December sees our focus shift to comet C/2022 E3 (ZTF). It is very possible that this comet will be the brightest comet in 2023. While not expected to be a Great Comet, it should become a nice borderline naked eye object in January and February. Unlike many comets that are at their best close to the horizon in twilight, ZTF will be placed high up in a dark sky, first for northern hemisphere observers and then starting in February for the southern hemisphere.

This month, ZTF is a rapidly brightening object starting the month around magnitude 8.6 and finishing the year around 6.9. If it continues its recent brightening trend, it could be a 4th magnitude object at its best.

A few more comets are expected to be brighter than magnitude 10 in December. Northern hemisphere observers can observe C/2020 V2 (ZTF) at 9th magnitude and C/2022 A2 (PANSTARRS) at 9-10th magnitude while southern observers have C/2017 K2 (PANSTARRS) at magnitude 8.

Among the fainter targets, 29P/Schwassmann-Wachmann has once again experienced a series of major outbursts and is currently a 11th magnitude object near opposition in Gemini/Auriga.

Last month the ALPO Comets Section received 95 magnitude estimates and 42 images/sketches of comets C/2022 P1 (NEOWISE), C/2022 E3 (ZTF), C/2022 A2 (PANSTARRS), C/2021 Y1 (ATLAS), C/2021 X1 (Maury-Attard), C/2021 T4 (Lemmon), C/2021 E3 (ZTF), C/2020 Y2 (ATLAS), C/2020 V2 (ZTF), C/2019 L3 (ATLAS), C/2017 K2 (PANSTARRS), 119P/Parker-Hartley, 118P/Shoemaker-Levy, 117P/Helin-Roman-Alu, 107P/Wilson-Harrington, 81P/Wild, 73P/Schwassmann-Wachmann, 61P/Shajn-Schaldach, and 29P/Schwassmann-Wachmann. A big thanks to our recent contributors: Dan Bartlett, Todd Bossaller, Denis Buczynski, Jef DeWit, J. J. Gonzalez, Jose Guilherme de Souza Aguiar, Christian Harder, Carl Hergenrother, Martin Mobberley, Uwe Pilz, Gregg, Ruppel, Tenho Tuomi, and Chris Wyatt.

The monthly ALPO Comet News PDF can be found here. A shorter version of this report is posted on a dedicated Cloudy Nights forum. All are encouraged to join the discussion over at Cloudy Nights.

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