April 3, 2021 – ALPO Comet News for April 2021
As announced in the Spring 2021 issue of the Journal of the ALPO, Michel Deconinck has graciously accepted to serve as Acting Assistant Coordinator of the ALPO Comets Section. Michel is an avid observers and master sketcher of not just comets but many astronomical phenomena. Two of his sketches are included in the PDF version of this month’s Report. Please join me in welcoming Michel to the ALPO team!
Two comets, C/2020 R4 (ATLAS) and C/2021 D1 (SWAN) reached 9th magnitude in March. While SWAN should now be fainter than magnitude 10.0 and fading, C/2020 R4 (ATLAS) will continue to brighten to about magnitude 8.5 as it passes 0.46 au from Earth on April 23. A number of fainter comets are also visible for large aperture visual observers including 7P/Pons-Winnecke which is brightening to a 11th magnitude maximum in June/July. This marks 7P’s 25th observed return and is part of a run of low numbered periodic comets returning in 2021.
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.
- Carl Hergenrother
March 5, 2021 – ALPO Comet News for March 2021
Not sure if we’ll have any comets brighter than 10th magnitude this month though there are two contenders. C/2020 R4 (ATLAS) may break the magnitude 10 barrier at the end of March but this is uncertain as the comet has not been observed since early January (due to being too close to the Sun). Newly discovered C/2021 D1 (SWAN) is close to the magnitude 10 barrier but it appears likely that it is as bright as it will get at 10-11th magnitude. In the meantime, there are many other comets between magnitude 10 and 13 that are good targets for CCD imagers and large aperture visual observers. Though still around 18th magnitude, imagers are encouraged to monitor C/2020 A1 (Leonard) which may become a nice object in December.
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.
- Carl Hergenrother
February 4, 2021 – ALPO Comet News for February 2021
For the second month in a row, no comets are expected to be brighter than 10th magnitude. Hopefully, this changes in March with C/2020 R4 (ATLAS). In the meantime, there are nearly a dozen comets between magnitude 10 and 13 that are good targets for CCD imagers and large aperture visual observers including 88P/Howell, 156P/Russell-LINEAR, 141P/Machholz, C/2019 N1 (ATLAS), C/2020 M3 (ATLAS), C/2021 A2 (NEOWISE), and P/2016 J3 = P/2021 A3 (STEREO).
Recently discovered C/2020 A1 (Leonard) may be a nice object in December. Currently a faint 18-19th magnitude object, CCD imagers are encouraged to monitor it as it brightens.
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.
- Carl Hergenrother
January 3, 2021 – ALPO Comet News for January 2021
While many of us are happy to see the end of 2020, it was actually quite a good year for comet observing. No less than 13 comets were observed at magnitude 10.0 or brighter. The comet highlight of the year was C/2020 F3 (NEOWISE) which was the most impressive comet for northern hemisphere observers since C/1995 O1 (Hale-Bopp) in 1997.
Though it is unlikely 2021 will deliver another NEOWISE-type event, the year is predicted to see a large number of reasonably bright short-period comets, though most won’t be bright till the 2nd half of the year. As a result, 2021 will start off slow with no comets expected to be brighter than 10th magnitude in January. We may need to wait till February or March when long-period comet C/2020 R4 (ATLAS) could become bright enough for small aperture observers.
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.
- Carl Hergenrother
December 3, 2020 – ALPO Comet News for December 2020
November turned out to be a great month for comet observers with 101 magnitude estimates of 9 comets and 44 images of 10 comets being submitted to the Comets Section. C/2020 S3 (Erasmus) led the pack as it brightened to 6th magnitude. C/2020 M3 (ATLAS), 156P/Russell-LINEAR and 88P/Howell were also visible between 7th and 10th magnitude. This month, Erasmus will be too close to the Sun for ground-based observers. As is fitting for 2020, we will be able to follow Erasmus virtually in images taken by the SOHO and STEREO spacecraft. C/2020 M3, 156P, and 88P will be fading but still bright enough for small aperture observers. For those willing to try fainter objects, 11P/Tempel-Swift-LINEAR, 29P/Schwassmann-Wachmann, 141P/Machholz, 398P/Boattini, and disintegrating C/2020 P1 (NEOWISE) will be between 10th and 14th magnitude.
The monthly ALPO Comet News PDF can be found here. Note with all of the recent comet activity, this report is a bit large in size. 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.
- Carl Hergenrother
November 1, 2020 – ALPO Comet News for November 2020
Three comets are expected to be brighter than 10th magnitude this month, 88P in the evening sky and C/2020 M3 (ATLAS) and C/2020 S3 (Erasmus) in the morning. 88P/Howell should fade from 9th to 10th magnitude this month. Long-period comet C/2020 M3 (ATLAS) will spend most of the month around 7-8th magnitude. Recent discovery, C/2020 S3 (Erasmus) starts the month around 9th magnitude and could be between 6th and 7th magnitude before moving too close to the Sun for most observers towards the latter half of the month. A couple of other comets may be observable hat are between 10th and 12th magnitude, including 156P/Russell-LINEAR and C/2020 P1 (NEOWISE).
The monthly ALPO Comet News PDF can be found here. Note with all of the recent comet activity, this report is a bit large in size. 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.
- Carl Hergenrother
October 7, 2020 – ALPO Comet News for October 2020
Two comets are expected to be good targets for small aperture observers: fading 88P/Howell (8th to 9th magnitude) and brightening C/2020 M3 (ATLAS) (9th to 8th magnitude). C/2020 P1 (NEOWISE), not to be confused with this year’s brightest comet C/2020 F3 (NEOWISE), could brighten above 10th magnitude but will only be visible to southern hemisphere observers at low elevations during the first week of the month. Assuming it survives perihelion, which may be unlikely as the comet is intrinsically faint and dynamically new, C/2020 P1 could be visible to northern observers as a faint visual object during the last week of the month. Among fainter comets to watch (10-12th mag) are departing comets C/2020 F3 (NEOWISE) and C/2020 Q1 (Borisov) and inbound comet C/2020 S3 (Erasmus).
The monthly ALPO Comet News PDF can be found here. Note with all of the recent comet activity, this report is a bit large in size. A shorter version of this report is posted on a dedicated Cloudy Nights forum (https://www.cloudynights.com/topic/733309-alpo-comet-news-for-october-2020/). All are encouraged to join the discussion over at Cloudy Nights.
- Carl Hergenrother
September 1, 2020 – ALPO Comet News for September 2020
The bright comets of the past few months are now fading. While C/2020 F3 (NEOWISE) starts the month around 9th magnitude, both C/2017 T2 (PANSTARRS) and C/2019 U6 (Lemmon) have faded to 11-12th magnitude. Taking their place are short-period comet 88P/Howell, which comes to perihelion this month and should be 8th magnitude, and two newly discovered long-period comets, C/2020 M3 (ATLAS) and C/2020 P1 (NEOWISE). The new ATLAS comet could be a nice small telescope object over the next few months. The latest NEOWISE comet is a little more uncertain and may only become bright enough for small aperture observers in late September and early October from the southern hemisphere.
The monthly ALPO Comet News PDF can be found here. Note with all of the recent comet activity, this report is a bit large in size. A shorter version of this report is posted on a dedicated Cloudy Nights forum (https://www.cloudynights.com/topic/726880-alpo-comet-news-for-september-2020/). All are encouraged to join the discussion over at Cloudy Nights.
- Carl Hergenrother
August 5, 2020 – ALPO Comet News for August 2020
C/2020 F3 (NEOWISE) was the celestial highlight of July and likely the best comet of 2020. NEOWISE is now rapidly fading but still a visually and photographically impressive object well placed for observation in the evening sky. August will see it fade from around 6th to 9th magnitude. By the end of August, short-period comet 88P/Howell will challenge NEOWISE’s place as the “brightest comet in the sky”. 2P/Encke, C/2017 T2 (PANSTARRS), and C/2019 U6 (Lemmon) start the month around 9-10th magnitude but fade throughout the month.
The monthly ALPO Comet News PDF can be found here. Note with all of the recent comet activity, this report is a bit large in size. A shorter version of this report is posted on a dedicated Cloudy Nights forum (https://www.cloudynights.com/topic/721655-alpo-comet-news-for-august-2020/). All are encouraged to join the discussion over at Cloudy Nights.
- Carl Hergenrother
July 3, 2020 – ALPO Comet News for July 2020
Comet C/2020 F3 (NEOWISE) is ~1st magnitude in the morning sky!
First there was C/2019 Y4 (ATLAS), the “Great Comet” that couldn’t hold itself together. Then along came C/2020 F8 (SWAN), the bright consolation prize that decided to star in its own break-up act. After the back-to-back let downs of ATLAS and SWAN, C/2020 F3 (NEOWISE) is at perihelion and currently as bright as 1st magnitude. Though it isn’t the best placed object for observing and will fade as the month progresses, NEOWISE should be a memorable comet and perhaps the best since C/2011 L4 (PANSTARRS), the Really Good Comet of 2013.
In addition to NEOWISE, there are a number of fainter comets within reach of small apertures. In the evening we have C/2019 U6 (Lemmon) at 6th-7th magnitude and 88P/Howell and C/2017 T2 (PANSTARRS) at 9th magnitude. Frequent inner solar system visitor 2P/Encke begins July at 7th-8th magnitude though only for southern hemisphere observers.
The monthly ALPO Comet News PDF can be found here. Note with all of the recent comet activity, this report is a bit large in size. A shorter version of this report is posted on a dedicated Cloudy Nights forum (https://www.cloudynights.com/topic/715659-alpo-comet-news-for-july-2020/). All are encouraged to join the discussion over at Cloudy Nights.
- Carl Hergenrother
