Comet Chasing in June


Comet chasing is the visual observation of telescopic comets.  Jump to:  Observing synopses    Summary data

News


May offers one comet visible in small telescope, but many more visible in larger instruments.
  • 2020 T2 (Palomar) will reach perihelion in mid July. It is currently predicted to reach maximum brightness of magnitude 10.5 in late June. 

  • 2020 J1 (SONEAR) passed perihelion in mid April.

  • C/2017 K2 (PANSTARRS) will reach perihelion in mid December 2022. It is predicted to reach maximum brightness of magnitude 6.5 in mid January 2023.

  • 6P/d'Arrest will next reach perihelion in mid September when it is predicted to reach maximum brightness of magnitude 10.8. 

  • 7P/Pons-Winnecke passed perihelion in late May. On May 27 this comet passed within 0.4 AU of the earth. It is currently predicted to reach maximum brightness of magnitude 11.2 in early June.

  • C/2020 R4 (Atlas) passed perihelion in early March. On March 1, this comet passed within 0.5 AU of the earth. This comet had an outburst in late April, brightening by as much as a magnitude. 

  • 141P/Machholz was reported to be in outburst on March 5 (up to 3 magnitudes). Other reports suggested that it may have been disintegrating. As of March 16 it had faded to magnitude 15.6. This comet passed perihelion on December 16. In mid January 2021 is passed within 0.5 AU of the earth. Discovered in 1994, this comet has many known separate fragments, at least one dating back to that time. A total of at least 8 have been observed at various apparitions. In December 2020 Michael Jäger reported three fragments. On or near January 1, 2020 the main part of the comet had an outburst of 2 magnitudes and it is this part that is currently visually observable. 

  • C/2021 A1 (Leonard) was discovered on January 3 by by G. J. Leonard at Mount Lemmon Observatory. It will reach perihelion on January 3, 2022. It may become visible to the naked eye in mid December 2021. It is currently very faint and not visualy observable. 

  • C/2021 A2 (NEOWISE) passed perihelion in late January. In early February this comet will pass within 0.5 AU of the earth. It is currently predicted to reach a maximum brightness of magnitude 11 in early February.

  • C/2021 A4 (NEOWISE) passed perihelion in mid-March.

  • P/2016 J3 (STEREO) passed perihelion on January 25, when it passed within 0.5 AU of the earth. This comet unexpectedly returned early, based on the orbit that was calculated for it in 2016.

  • 246P/NEAT passed perihelion in late February 2021. It is currently predicted to reach maximum brightness of magnitude 14.7 in late June.

  • C/2020 M3 (ATLAS) passed perihelion in late October. On October 25, this comet passed within 0.4 AU of the earth. It is currently predicted to attain maximum brightness of magnitude 7.5 in early November 9.

  • C/2020 S3 (Erasmus) passed perihelion on December 12 and is not observable. 

  • 11P/Tempel-Swift-LINEAR passed perihelion on November 25. 

  • C/2019 N1 (ATLAS) passed perihelion early December. It hasn't been observed since August. Based on the last observation, it is predicted to reach a maximum brightness of magnitude 9.7 in early January 2021.

  • C/2020 R4 (ATLAS) passed perihelion in early March. 

  • 2021 D1 (SWAN) was discovered on SWAN images obtained by the SOHO solar observing spacecraft in late February. It is past perihelion, which occurred in late February.  

  • 29P/Schwassmann-Wachmann had an outburst on January 15. This comet has frequent outbursts, resulting in a brightening of 0.5 - 1.0 magnitudes, which occur roughly every 59 days, typically taking 5-10 days to subside. Up to three subsequent outbursts may occur 5-10 days afterward, each typically smaller than the last, although on some occasions they can be even brighter than the first. These outbursts make 29P one of the most interesting comets to follow, both visually and scientifically. 29P/Schwassmann-Wachmann has a 14.8-year orbital period, and last passed perihelion in early March 2019. It varies in its distance from the Sun from 5.8 AU (at perihelion) to 6.3 AU (at aphelion), which is an unusually small variation for a comet, and remains quite far from the sun at all times. This means that it can be observed more or less continuously.

  • C/2019 L3 (ATLAS) will reach perihelion on 2022 January 9, when it may be magnitude 11

Comets that have apparently disentegrated: C/2020 Q1 (Borisov), C/2020 P1 (NEOWISE), and C/2019 Y4 (ATLAS). Beware that various other online sources often fail to keep track of whether or not a comet still exists!

Comet Visibility in the Eyepiece

This page uses code developed for SkyTools to predict the visibility of a comet in the eyepiece.  Predicting how much aperture is required to see a comet is a very complex task.  Have a look for yourself: a comparison of the predictions below (such as "visible in small telescopes") to the magnitude of each comet shows just how poor an indicator the magnitude alone really is. When you read below that a particular aperture is required to see a comet you can have a reasonable degree of confidence that the comet can in fact be seen in the eyepiece. But always remember, comets are like cats. They both have tails and do what they want, and not always what we expect. This is one of the things that makes comet chasing interesting!

Observing Synopses for June


Explanation of Comet Synopses and charts (read this if you have questions)

C/2020 T2 (Palomar): An evening comet visible in small telescopes
This comet begins the month in Bootes at magnitude 10.5. Look for a 5.5' coma. It should fade slowly.  FINDER CHART

Latitude Visibility May 29 Visibility June 5 Visibility June 12 Visibility June 19 Visibility June 26 Nights Visible
55o N High during evening twilight at ~23:50 High during evening twilight at ~23:50 Fairly high during evening twilight at ~23:50 Fairly high in the western sky during evening twilight at ~23:50 Fairly high in the western sky during evening twilight at ~23:40 1-
40o N High at ~21:30 High at ~21:30 High during evening twilight at ~21:30 Fairly high in moonlight at ~23:40 High during evening twilight at ~21:30 1-
Equator High at ~21:10 High at ~20:40 High at ~20:10 High in moonlight at ~19:30 High at ~19:40 1-
30o S Fairly high at ~20:40 Fairly high at ~20:40 High at ~20:20 High in moonlight at ~19:40 High at ~19:20 1-

7P/Pons-Winnecke: A morning comet visible in small telescopes
This comet begins the month in Capricornus at magnitude 11.8. Look for a 20" coma. It should fade slowly, moving into Sculptor by month's end. The best visibility is early in the month as seen from the southern hemisphere.  FINDER CHART

Latitude Visibility May 29 Visibility June 5 Visibility June 12 Visibility June 19 Visibility June 26 Nights Visible
55o N Not visible Not visible Not visible Not visible Not visible 1-3
40o N Fairly high during morning twilight at ~02:50 Fairly high in the southern sky during morning twilight at ~02:50 Fairly high in the southern sky during morning twilight at ~02:50 Low in the southern sky during morning twilight at ~02:50 Not visible 1-
Equator High during morning twilight at ~04:40 High in moonlight at ~04:40 High at ~04:40 High at ~04:40 High during morning twilight at ~04:50 1-
30o S High during morning twilight at ~05:30 High in moonlight at ~04:50 High at ~04:50 High at ~04:50 High during morning twilight at ~05:40 1-

C/2020 J1 (SONEAR): An evening comet visible in a 10-inch (25 cm) telescope
This comet begins the month in Libra at magnitude 12.9. Look for a 1' coma. It should fade slowly, moving into Virgo by month's end. The best visibility is early in the month as seen from the southern hemisphere.  FINDER CHART

Latitude Visibility May 29 Visibility June 5 Visibility June 12 Visibility June 19 Visibility June 26 Nights Visible
55o N Not visible Not visible Not visible Not visible Not visible 1-16
40o N Fairly high in the southern sky at ~22:20 Fairly high in the southern sky at ~21:40 Fairly high during evening twilight at ~21:30 Fairly high during evening twilight at ~21:20 Fairly high during evening twilight at ~21:30 1-
Equator High at ~21:40 High at ~21:40 High at ~21:00 High in moonlight at ~19:30 High at ~19:40 1-
30o S High at ~20:40 High at ~21:40 High at ~21:00 Fairly high in moonlight at ~00:30 High at ~19:20 1-

C/2017 K2 (PANSTARRS): An evening comet visible in a 12.5-inch (32 cm) telescope
This comet begins the month in Hercules at magnitude 13.8. Look for a 35" coma. It should brighten slowly.  FINDER CHART

Latitude Visibility May 29 Visibility June 5 Visibility June 12 Visibility June 19 Visibility June 26 Nights Visible
55o N High during morning twilight at ~00:00 High during morning twilight at ~00:00 High during morning twilight at ~00:00 High during morning twilight at ~00:00 High during evening twilight at ~00:00 1-
40o N High at ~23:20 High at ~01:00 High at ~00:30 High at ~01:00 High at ~21:50 1-
Equator Fairly high in the northern sky at ~22:00 High at ~01:00 High at ~00:20 High at ~01:20 Fairly high at ~20:30 1-
30o S Low in the northern sky in moonlight at ~01:30 Low in the northern sky at ~01:00 Low in the northern sky at ~00:20 Low in the northern sky in moonlight at ~00:20 Low in the northern sky in moonlight at ~23:00 1-

6P/d'Arrest: An evening comet visible in a 14-inch (36 cm) telescope
This comet begins the month in Hercules at magnitude 16.0. Look for a 35" coma. It should brighten rapidly.  FINDER CHART

Latitude Visibility May 29 Visibility June 5 Visibility June 12 Visibility June 19 Visibility June 26 Nights Visible
55o N Not visible Not visible Not visible Not visible High during evening twilight at ~00:00 15-
40o N Not visible High at ~23:30 High at ~23:10 High at ~01:00 High at ~21:50 1-
Equator Not visible High at ~23:40 High at ~23:00 High at ~01:20 High at ~20:20 1-
30o S Not visible Not visible High at ~23:00 Fairly high in the western sky at ~01:20 Fairly high at ~19:30 1-

C/2019 T4 (ATLAS): A southern hemisphere evening comet visible in a 16-inch (41 cm) telescope
This comet begins the month in Pyxis at magnitude 14.3. Look for a 20" coma. It should remain constant. The best visibility is early in the month as seen from the southern hemisphere.  FINDER CHART

Latitude Visibility May 29 Visibility June 5 Visibility June 12 Visibility June 19 Visibility June 26 Nights Visible
55o N Not visible Not visible Not visible Not visible Not visible  
40o N Not visible Not visible Not visible Not visible Not visible  
Equator Fairly high during evening twilight at ~19:10 Fairly high during evening twilight at ~19:20 Fairly high in the western sky during evening twilight at ~19:20 Fairly high in the western sky during evening twilight at ~19:10 Low in the western sky during evening twilight at ~19:10 1-
30o S High at ~18:40 High at ~18:40 High at ~18:30 High during evening twilight at ~18:30 Fairly high at ~18:40 1-

C/2019 L3 (ATLAS): A far-northern morning comet visible in very large telescopes
This comet begins the month in Perseus at magnitude 12.5. Look for a 3.5' coma. It should brighten slowly, moving into Auriga by month's end.  FINDER CHART

Latitude Visibility May 29 Visibility June 5 Visibility June 12 Visibility June 19 Visibility June 26 Nights Visible
55o N Not visible Not visible Not visible Not visible Not visible  
40o N Not visible Not visible Low in the northern sky during morning twilight at ~02:40 Low in the northern sky during morning twilight at ~02:40 Low in the northern sky during morning twilight at ~02:50 12-24, 26-
Equator Not visible Not visible Not visible Not visible Not visible  
30o S Not visible Not visible Not visible Not visible Not visible  

10P/Tempel: A southern hemisphere morning comet visible in very large telescopes
This comet begins the month in Pisces at magnitude 12.2. Look for a 3' coma. It should fade by about 0.9 magnitudes, moving into Cetus by month's end. The best visibility is early in the month as seen from the southern hemisphere.  FINDER CHART

Latitude Visibility May 29 Visibility June 5 Visibility June 12 Visibility June 19 Visibility June 26 Nights Visible
55o N Not visible Not visible Not visible Not visible Not visible  
40o N Not visible Not visible Not visible Not visible Not visible  
Equator Fairly high in the eastern sky during morning twilight at ~04:50 Fairly high in the eastern sky during morning twilight at ~04:40 Fairly high in the eastern sky during morning twilight at ~04:40 Fairly high during morning twilight at ~04:40 Fairly high during morning twilight at ~04:50 1-
30o S Fairly high in the eastern sky during morning twilight at ~05:30 Fairly high in the eastern sky during morning twilight at ~05:30 Fairly high in the eastern sky at ~05:30 Fairly high at ~05:30 Fairly high during morning twilight at ~05:40 1-

15P/Finlay: A southern hemisphere morning comet visible in very large telescopes
This comet begins the month in Cetus at magnitude 13.7. Look for a 2' coma. It should brighten by about 0.6 magnitudes, moving into Aries by month's end.  FINDER CHART

Latitude Visibility May 29 Visibility June 5 Visibility June 12 Visibility June 19 Visibility June 26 Nights Visible
55o N Not visible Not visible Not visible Not visible Not visible  
40o N Not visible Not visible Not visible Not visible Not visible  
Equator Not visible High in moonlight at ~04:40 High at ~04:40 Fairly high at ~04:40 Not visible 2-23, 27-
30o S Not visible High in moonlight at ~05:20 High at ~05:20 Fairly high at ~05:30 Fairly high during morning twilight at ~05:30 2-23, 26-

4P/Faye: A morning comet visible in very large telescopes
This comet begins the month in Pisces at magnitude 14.0. Look for a 2.5' coma. It should brighten by about 0.8 magnitudes, moving into Aries by month's end.  FINDER CHART

Latitude Visibility May 29 Visibility June 5 Visibility June 12 Visibility June 19 Visibility June 26 Nights Visible
55o N Not visible Not visible Not visible Not visible Not visible  
40o N Not visible Not visible Low in the eastern sky during morning twilight at ~02:40 Fairly high in the eastern sky during morning twilight at ~02:40 Fairly high in the eastern sky during morning twilight at ~02:50 11-
Equator Fairly high during morning twilight at ~04:40 Fairly high in moonlight at ~04:40 High at ~04:40 High at ~04:40 High during morning twilight at ~04:50 1-
30o S Fairly high during morning twilight at ~05:20 Fairly high in moonlight at ~05:20 Fairly high at ~05:20 Fairly high at ~05:30 Fairly high during morning twilight at ~05:40 1-

C/2020 R4 (ATLAS): An evening comet visible in very large telescopes
This comet begins the month in Leo at magnitude 13.7. Look for a 2.5' coma. It should fade rapidly.  FINDER CHART

Latitude Visibility May 29 Visibility June 5 Visibility June 12 Visibility June 19 Visibility June 26 Nights Visible
55o N Not visible Not visible Not visible Not visible Not visible  
40o N High at ~21:20 High at ~21:30 Not visible Not visible Not visible 1-11
Equator High at ~19:30 High at ~19:30 High at ~19:30 Not visible Not visible 1-14
30o S Fairly high at ~18:50 Fairly high at ~18:40 Fairly high at ~18:40 Not visible Not visible 1-13

C/2019 F1 (ATLAS-Africano): A southern hemisphere morning comet visible in very large telescopes
This comet begins the month in Octans at magnitude 14.8. Look for a 20" coma. It should remain constant. The best visibility is early in the month as seen from the southern hemisphere.  FINDER CHART

Latitude Visibility May 29 Visibility June 5 Visibility June 12 Visibility June 19 Visibility June 26 Nights Visible
55o N Not visible Not visible Not visible Not visible Not visible  
40o N Not visible Not visible Not visible Not visible Not visible  
Equator Not visible Not visible Not visible Not visible Not visible  
30o S Fairly high in the southern sky at ~20:40 Fairly high in moonlight at ~05:00 Fairly high at ~05:00 Fairly high at ~05:00 Fairly high in the southern sky at ~19:20 1-

246P/NEAT: A morning comet visible in very large telescopes
This comet begins the month in Sagittarius at magnitude 14.9. Look for a 35" coma. It should remain constant. The best visibility is mid-month as seen from the southern hemisphere.  FINDER CHART

Latitude Visibility May 29 Visibility June 5 Visibility June 12 Visibility June 19 Visibility June 26 Nights Visible
55o N Not visible Not visible Not visible Not visible Not visible  
40o N Not visible Fairly high in the southern sky at ~02:20 Low in the southern sky at ~02:00 Low in the southern sky at ~01:30 Not visible 1-22, 28-
Equator Not visible High at ~02:30 High at ~02:00 High at ~01:30 Low in the eastern sky at ~20:30 1-23, 26-
30o S Not visible High at ~02:30 High at ~02:00 High at ~01:40 Fairly high in the eastern sky at ~19:30 1-23, 26-

C/2020 F5 (MASTER): A southern hemisphere morning comet visible in very large telescopes
This comet begins the month in Sculptor at magnitude 15.0. Look for a 40" coma. It should brighten slowly. The best visibility is late in the month as seen from the southern hemisphere.  FINDER CHART

Latitude Visibility May 29 Visibility June 5 Visibility June 12 Visibility June 19 Visibility June 26 Nights Visible
55o N Not visible Not visible Not visible Not visible Not visible  
40o N Not visible Not visible Not visible Not visible Not visible  
Equator Not visible High in moonlight at ~04:40 High at ~04:40 High at ~04:40 Not visible 1-23, 30-
30o S Not visible High in moonlight at ~05:20 High at ~05:20 High at ~05:20 Not visible 1-23, 30-

Summary Data for This Month's Telescopic Comets


Comets brighter than 16th magnitude.  This table is updated as necessary. The last column indicates the date of the last observation used to compute these values.  The constellation listed is where the comet was on the first of the month.
Comet Constellation

June 1st

June 15th

June 30th

Observations as of (UT)
Mag Diam Mag Diam Mag Diam
C/2020 T2 (Palomar) Bootes 10.5 5.6' 10.5 5.4' 10.6 5.1' 2021 May 31
7P/Pons-Winnecke Capricornus 11.8 20" 11.9 20" 12.2 19" 2021 May 18
10P/Tempel Pisces 12.2 3.2' 12.7 3.2' 13.1 3.2' 2021 April 20
C/2019 L3 (ATLAS) Perseus 12.5 3.6' 12.4 3.7' 12.3 3.7' 2021 May 15
C/2020 J1 (SONEAR) Libra 12.9 1.2' 13.1 1.1' 13.3 59" 2021 May 31
15P/Finlay Cetus 13.7 1.8' 13.2 1.9' 13.0 1.8' 2021 May 23
C/2020 R4 (ATLAS) Leo 13.7 2.3' 14.7 1.8' 15.6 1.4' 2021 May 17
C/2017 K2 (PANSTARRS) Hercules 13.8 34" 13.7 34" 13.5 35" 2021 May 14
4P/Faye Pisces 14.0 2.3' 13.6 2.4' 13.2 2.7' 2021 May 18
C/2019 T4 (ATLAS) Pyxis 14.3 21" 14.3 21" 14.2 20" 2021 May 31
C/2019 N1 (ATLAS) Pictor 14.6 2.7' 14.9 2.6' 15.2 2.5' 2021 May 12
C/2019 F1 (ATLAS-Africano) Octans 14.8 21" 14.8 21" 14.8 21" 2021 May 31
246P/NEAT Sagittarius 14.9 34" 14.8 36" 14.8 36" 2021 May 18
C/2020 F5 (MASTER) Sculptor 15.0 39" 15.0 41" 14.9 42" 2021 May 20
C/2018 U1 (Lemmon) Ophiuchus 15.1 21" 15.1 21" 15.0 21" 2021 May 17
C/2020 S3 (Erasmus) Pegasus 15.2 18" 15.4 18" 15.5 18" 2021 May 20
117P/Helin-Roman-Alu Virgo 15.2 28" 15.2 26" 15.3 25" 2021 May 31
C/2021 D1 (SWAN) Gemini 15.3 2.0' 15.9 1.8' 16.5 1.7' 2021 April 23
C/2019 K7 (Smith) Draco 15.8 19" 15.9 19" 16.0 19" 2021 April 8
29P/Schwassmann-Wachmann Taurus 15.9 23" 15.9 23" 15.8 24" 2021 April 4
6P/d'Arrest Hercules 16.0 30" 14.9 33" 13.8 35" 2021 May 5
67P/Churyumov-Gerasimenko Aquarius 16.6 26" 16.1 29" 15.5 34" 2021 May 24
*In solar conjunction and generally not visible

For information about specific comets see Gary W. Kronk's Cometography 

Further reading: see Comet Chasing, Sky & Telescope, April 2005, pg. 83.

Make your own custom charts for your location and telescope/binoculars: software for visual comet observing

New: software for comet imaging
 

Links

Skyhound's Guide to Comets
Skyhound's Guide to Finding Comets
BAA Comet Section
Weekly Information About Bright Comets
Cometography