Comet Section        

 
 

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.

 
 

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.

 
 

November 2, 2019 – ALPO Comet News for November 2019

November finds us in-between bright comets. C/2018 W2 (Africano) is now too faint for small aperture telescopes while C/2017 T2 (PANSTARRS) is at least a month away from becoming an easy object. Fortunately it will continue to brighten over the next few months and should provide a nice target for much of the first half of 2020. CCD imagers are encouraged to keep a detector on interstellar comet 2I/Borisov which will be around 15-16th magnitude this month.

Other comets brighter than 13th magnitude this month include 29P/Schwassmann-Wachmann, 260P/McNaught, and C/2018 N2 (ASASSN). Fainter comets of interest include 289P/Blanpain and the aforementioned 2I/Borisov.

The monthly ALPO Comet News PDF can be found here. An edited version of this report is posted on the Cloudy Nights forum at (https://www.cloudynights.com/topic/682477-alpo-comet-news-for-november-2019/). Everyone is invited to join the discussion at our Cloudy Nights forum.

 
 

THE COMETS OF 2014

2013-December-31

The following is an updated and expanded version of the ALPO Comet Section Report from the Winter 2014 JALPO (56-1).

Happy New Year!

2013 may not have produced its advertised comet of the century but it did produce 4 naked eye comets (though all were just marginally so). 2014 will also bring many comet observing opportunities with the discovery of additional new bright comets likely.

C/2013 R1 (Lovejoy) will start the year around 5-6th magnitude and still be visible in small telescopes (brighter than 10th magnitude) till March as it moves away from the Sun and Earth following its 0.81 AU perihelion on 2013 December 21. During January Lovejoy will slowly fade and can be found moving from Hercules to Ophiuchus.

A bit of a surprise (and an addition to the report published in JALPO) is Comet C/2012 X1 (LINEAR). Initially a faint comet, LINEAR was not expected to get brighter than ~12th magnitude near the time of its February 21st perihelion at 1.60 AU from the Sun. Surprisingly the comet was observed as bright as 8th magnitude in November 2013 after experiencing a major ~6 magnitude outburst. Though the outburst has subsided, the comet remains bright at around 9th magnitude at the end of December 2013. Forecasting the brightness of an outburst prone comet is always difficult but it is very possible that this comet will remain a nice small telescope comet through perihelion and beyond. The comet is a morning object and will remain so till the middle of the year. It is observable from the Northern Hemisphere until July and will become visible from the Southern Hemisphere starting in mid-February. In January, LINEAR starts the month around magnitude 8-9 to the southeast of the ‘head’ of Serpens Caput in the morning sky. As the month progresses the comet will move through northern Ophiuchus. By the end of January, comets LINEAR and Lovejoy will be located within 4° of each other.

In addition to Lovejoy, three more long-period comets are expected to become brighter than 7th magnitude in 2014. Comet C/2012 K1 (PANSTARRS) will reach perihelion on August 27 at a distance of 1.05 AU from the Sun. Starting the year at 13th magnitude, the comet will brighten to 7th magnitude in June and July before passing solar conjunction (unfortunately on the far side of the Sun). When the comet remerges from the glare of the Sun in September it will be a 6th magnitude object only observable from the Southern Hemisphere. PANSTARRS should still be around 9th magnitude by the end of the year.

Our next comet was discovered by Michael Ory at the Oukaimeden Observatory in Morocco at 18th magnitude. Comet C/2013 V5 (Oukaimeden) will reach perihelion on October 2 at a distance of 0.66 AU from the Sun. It is too early to be sure, but the comet should be brighter than 10th magnitude by August and as bright as 5-6th magnitude in late September when it passes within 0.46 AU of Earth. Northern Hemisphere observers will loss sight of the comet in mid-September though Southern observers will still be able to follow it into October.

Back in early October, Comet ISON made the news as it came close enough to Mars to allow NASA’s Mars orbiting spacecraft to image it. Comet C/2013 A1 (Siding Spring) will pass even closer to Mars on October 19, 2014. Definitely expect to hear more about this comet as it passes within ~150,000 km of Mars resulting in some high-resolution imaging from Mars. For us on Earth the comet should be a 7th magnitude object around its October 2 perihelion (r = 1.40 AU from the Sun). Again Southern observers will see this comet at its best as it will only become observable for Northern observers in November.

The next four comets may not become brighter than 10th magnitude but are worth mentioning. Short-period comet 209P/LINEAR will pass within 0.06 AU of Earth in late May at ~10-11th magnitude (r = 0.97 AU). Dust released by LINEAR during past orbits may result in a significant meteor shower on the night of May 24, 2014. The close approach will also allow imaging by radar telescopes giving us a resolved look at its nucleus. 15P/Finlay is another short-period comet which may be approaching 10th magnitude at the end of the year as it passes perihelion on December 27 (r = 0.98 AU). 2014 will bring not only resolved images of the nuclei of comets C/2013 A1 (Siding Spring) and 209P/LINEAR, but extremely high-resolution images of the nucleus of short-period comet 67P/Churyumov-Gerasimenko. This year the ESA Rosetta spacecraft will rendezvous with 67P and begin a multi-year campaign to study the comet at close-range. In 2014, 67P will still be around 3 AU from the Sun and around 18th magnitude.

The final comet is currently not a comet at all. Asteroid 2013 UQ4 was discovered by the Catalina Sky Survey on a very comet-like orbit with a period of hundreds of years. There is a good chance this asteroid is a comet that has either not turned on yet or its cometary activity is too weak to be detected. With its closest approach to the Sun on July 5 (1.08 AU) and to the Earth on July 10/11 (0.31 AU), 2013 UQ4 will be magnitude 12.9 if it remains inactive and possibly many magnitudes brighter if active.

Looking into 2015 and beyond there are two comets that could become nice small telescope objects near perihelion but will be faint in 2014. Monitoring their development in 2014 is essential for predicting their future performance. C/2013 US10 (Catalina) doesn’t reach perihelion until 2015 November 15 when it will be 0.82 AU from the Sun. The comet will also come within 0.73 AU of Earth in January of 2016 when it will be somewhere between 6th and 9th magnitude. As of the end of 2013, the comet is 7.8 AU from the Sun and 17th magnitude. Our other long-range comet is C/2013 X1 (PANSTARRS) which is currently even further out than US10 at 8.7 AU. Though now only 19th magnitude, it should substantially brighten when it reaches perihelion (1.30 AU on 2016 April 19) and closest to Earth (0.64 AU in late June 2016).

As always, the ALPO Comet Section thanks those who have sent observations during 2013 and solicit new images, drawings and magnitude estimates during the coming year. The Comet Section Image Gallery now contains 267 images of 56 comets including many of those mentioned above.

 
 

COMET ISON T – 1.5 DAYS AND COUNTING

2013-Nov-27

Comet ISON is still with us. Here is its current status:

- Millimeter wavelength observations detected a significant drop in gaseous production rates a few days ago which led many to worry that the nucleus may have disrupted. Though still a possibility, the comet’s recent behavior suggests that the drop was due to the end of a recent outburst and the comet may back to its ‘non-outburst’ level.

- Photometry conducted on visible light images taken with the STEREO and SOHO spacecraft show the comet’s decline in brightness to be stabilizing and a slow increase has begun. Still the comet was only around magnitude 3.5 to 4.0 as of yesterday though Matthew Knight of Lowell Observatory has  tweeted that the comet has brightened by a factor of ~4 since it entered the FOV of SOHO’s LASCO instrument last evening.

- Unless the comet undergoes another outburst or starts to rapidly brighten it will probably not be visible to the naked eye or small telescopes at perihelion. Right now it looks like a peak magnitude of -2 to -4 is expected.

- The best resources to follow the action is at:

SOHO LASCO C3 camera (in FOV right now) – http://sohowww.nascom.nasa.gov/data/realtime/c3/1024/latest.html

SOHO LASCO C2 camera (in FOV tomorrow) – http://sohowww.nascom.nasa.gov/data/realtime/c2/1024/latest.html

- Carl Hergenrother (Acting Co-coordinator ALPO Comet Section)

 
 

Each ALPO section now has access to a “blog” and an image gallery.  The blog can be used by any coordinator or section associate to post special alerts and images.  The gallery is also available for posting and archiving section images.

There are many advantages to using these applications on our website, including the ability to search posts by category, content and the ability to perform keyword searches when looking for images.  There is also an option that will automatically post to a Yahoo group whenever a post is logged to your blog.  The blog also includes an events calendar.   The best part is that you don’t have to wait for someone else to post your alerts.  Posting an alert to the blog is just like creating a Word document.  You simply type, cut and paste images and post – no web experience necessary.

Of course this is all optional.  If you like the way things are now with your section, that’s fine.  Please note that the gallery will be used for future image posts, if the webmaster is asked to post images for you.

If you need an account for your section, contact Larry Owens   Larry.Owens@alpo-astronomy.org

Here’s a link to the gallery:  https://alpo-astronomy.org/gallery

Thanks,

Larry Owens

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