Comet Chasing in July

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

News

There is one comet visible in binoculars and small telescopes this month. Many more are visible in larger instruments.

  • C/2021 O3 (PANSTARRS) passed perihelion on April 21. In early May this comet will pass within 0.6 AU of the earth. It reached maximum brightness of magnitude in late April. 

  • 45P/Honda-Mrkos-Pajdusakova was only recently recovered. It passed perhilion on April 26, and was not seen prior. 

  • C/2019 T4 (ATLAS) passed perihelion in early June. 

  • C/2021 E3 (ZTF) passed perihelion in mid June.  June.

  • C/2022 E3 (ZTF) (be careful not to confuse with 2021 E3 (ZTF) above) will reach perihelion in mid January 2023. On January 12 this comet will pass within 0.3 AU of the earth. It is currently predicted to reach maximum brightness of magnitude 5.3 in late January.

  • C/2021 P4 (ATLAS) will reach perihelion at the end of July 2022. It is predicted to reach maximum brightness of magnitude 9 in late July..

  • C/2017 K2 (PANSTARRS) passed perihelion in mid December 2022. 

  • C/2019 L3 (ATLAS) passed perihelion on January 9.

  • 19P/Borrelly passed perihelion in early February and is fading.

  • 104P/Kowal reached perihelion in mid January 2022.

  • 67P/Churyumov-Gerasimenko passed perihelion in early November. On November 2 this comet passed within 0.4 AU of the earth.

  • C/2021 A1 (Leonard) was discovered on January 3, 2021 by by G. J. Leonard at Mount Lemmon Observatory. It passed perihelion on January 3, 2022. 

  • 29P/Schwassmann-Wachmann has frequent outbursts, typically 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/2014 UN271 (Bernardinelli-Bernstein) is an interesting Oort cloud comet that was recently reported as a result of the Dark Energy Survey. Soon after it was made public, images showed a cometary coma. Discovery credit goes to Pedro Bernardinelli and Gary Bernstein. This is a remarkable comet that was at 29 AU in 2014, with a perihelion of 10.9 AU in 2031. Its orbit extends out to 40,000 AU! It was unusually bright for its distance. Recent HST obsrvations that isolate the nucleus estimate the diamter to br between 120 and 140 km, making this possibly the largest comet nucleus yet measured. Because of its distant perihelion, this comet is not expected to become bright enough to be visually observed except in large instruments, and not until the end of the decade, but it is likely going to be the subject of intense scientific scrutiny. 

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 July

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

C/2017 K2 (PANSTARRS): An evening comet visible in binoculars
This comet begins the month in Ophiuchus at magnitude 8.7. Look for a 6' coma. It should brighten slowly.  FINDER CHART

Latitude Visibility July 2 Visibility July 9 Visibility July 16 Visibility July 23 Visibility July 30 Nights Visible
55o N Not visible Fairly high in the southern sky during evening twilight at ~00:00 Fairly high in the southern sky during evening twilight at ~23:40 Low in the southern sky during evening twilight at ~23:20 Low in the southern sky during evening twilight at ~22:50 1-
40o N High at ~22:40 Fairly high at ~00:50 High at ~21:40 High at ~21:20 Fairly high at ~21:10 1-
Equator High at ~22:40 Fairly high in the western sky at ~02:00 High at ~21:10 High at ~20:40 High at ~20:00 1-
30o S High at ~22:40 Fairly high in the western sky at ~02:30 High at ~20:40 High at ~20:40 High at ~20:00 1-

C/2021 E3 (ZTF): A southern hemisphere evening comet visible in a 6-inch (15 cm) telescope
This comet begins the month in Carina at magnitude 10.2. Look for a 4.5' coma. It should fade by about 1.0 magnitudes, moving into Vela by month's end. The best visibility is early in the month as seen from the southern hemisphere.  FINDER CHART

Latitude Visibility July 2 Visibility July 9 Visibility July 16 Visibility July 23 Visibility July 30 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 1-5
30o S Fairly high in moonlight at ~18:40 Fairly high during evening twilight at ~18:40 Fairly high at ~18:40 Fairly high in the western sky during evening twilight at ~18:50 Fairly high in the western sky during evening twilight at ~18:50 1-

C/2022 E3 (ZTF): An evening comet visible in a 10-inch (25 cm) telescope
This comet begins the month in Lyra at magnitude 14.0. Look for a 60" coma. It should brighten by about 0.7 magnitudes, moving into Hercules by month's end.  FINDER CHART

Latitude Visibility July 2 Visibility July 9 Visibility July 16 Visibility July 23 Visibility July 30 Nights Visible
55o N High during morning twilight at ~00:00 High during morning twilight at ~00:00 High during evening twilight at ~23:40 High during evening twilight at ~23:50 High during evening twilight at ~23:30 1-
40o N High at ~00:20 High at ~00:50 High at ~22:10 High at ~21:50 High at ~21:20 1-
Equator High at ~00:10 High at ~02:00 High at ~21:20 High at ~21:50 High at ~21:10 1-
30o S Fairly high in the northern sky at ~00:10 Fairly high in the northern sky in moonlight at ~23:40 Fairly high in the northern sky in moonlight at ~21:30 Fairly high in the northern sky at ~21:50 Fairly high in the northern sky at ~21:00 1-

C/2019 T4 (ATLAS): An evening comet visible in a 12.5-inch (32 cm) telescope
This comet begins the month in Virgo at magnitude 12.6. Look for a 1.5' coma. It should fade slowly. The best visibility is early in the month as seen from the southern hemisphere.  FINDER CHART

Latitude Visibility July 2 Visibility July 9 Visibility July 16 Visibility July 23 Visibility July 30 Nights Visible
55o N Not visible Not visible Not visible Not visible Not visible  
40o N Low in the western sky during evening twilight at ~21:20 Not visible Low in the western sky during evening twilight at ~21:00 Not visible Not visible 1-27, 29-30
Equator High in moonlight at ~19:30 High during evening twilight at ~19:20 High at ~19:30 High at ~19:30 Fairly high at ~19:20 1-
30o S High in moonlight at ~18:50 High during evening twilight at ~18:40 High at ~18:50 High at ~18:50 High at ~18:50 1-

22P/Kopff: A morning comet visible in a 16-inch (41 cm) telescope
This comet begins the month in Pisces at magnitude 11.6. Look for a 5.5' coma. It should remain constant.  FINDER CHART

Latitude Visibility July 2 Visibility July 9 Visibility July 16 Visibility July 23 Visibility July 30 Nights Visible
55o N Not visible Not visible Not visible Low in the eastern sky during morning twilight at ~01:00 Fairly high in the eastern sky during morning twilight at ~01:10 20-
40o N Fairly high in the eastern sky during morning twilight at ~02:40 Fairly high during morning twilight at ~02:50 Fairly high during morning twilight at ~03:00 High in moonlight at ~03:00 High at ~03:10 1-
Equator High at ~04:40 High at ~04:40 High during morning twilight at ~04:50 High in moonlight at ~04:40 High at ~04:40 1-
30o S High at ~05:20 High at ~05:20 High during morning twilight at ~05:30 High in moonlight at ~05:00 High at ~05:00 1-

C/2021 P4 (ATLAS): A northern hemisphere evening comet visible in an 18-inch (46 cm) telescope
This comet begins the month in Lynx at magnitude 10.4. Look for a 3' coma. It should brighten slowly, moving into Leo by month's end.  FINDER CHART

Latitude Visibility July 2 Visibility July 9 Visibility July 16 Visibility July 23 Visibility July 30 Nights Visible
55o N Not visible Not visible Not visible Not visible Not visible  
40o N Low in the western sky during evening twilight at ~21:10 Very low in the western sky during evening twilight at ~21:00 Not visible Not visible Not visible 1-13
Equator Very low in the western sky during evening twilight at ~19:10 Very low in the western sky during evening twilight at ~19:10 Very low in the western sky during evening twilight at ~19:10 Not visible Not visible 1-23, 28-28
30o S Not visible Not visible Not visible Not visible Not visible  

73P/Schwassmann-Wachmann: An evening comet visible in an 18-inch (46 cm) telescope
This comet begins the month in Leo at magnitude 14.8. Look for a 45" coma. It should brighten by about 1.0 magnitudes, moving into Virgo by month's end. The best visibility is late in the month as seen from the southern hemisphere.  FINDER CHART

Latitude Visibility July 2 Visibility July 9 Visibility July 16 Visibility July 23 Visibility July 30 Nights Visible
55o N Not visible Not visible Not visible Not visible Not visible  
40o N Fairly high in the western sky during evening twilight at ~21:20 Not visible Low in the western sky during evening twilight at ~21:00 Low in the western sky during evening twilight at ~20:50 Not visible 1-
Equator High in moonlight at ~19:20 High during evening twilight at ~19:20 Fairly high at ~19:20 Fairly high at ~19:20 Fairly high during evening twilight at ~19:20 1-
30o S Fairly high in moonlight at ~18:40 Fairly high during evening twilight at ~18:40 Fairly high at ~18:40 Fairly high at ~18:50 Fairly high during evening twilight at ~18:50 1-

C/2019 L3 (ATLAS): A southern hemisphere evening comet visible in very large telescopes
This comet begins the month in Canis Minor at magnitude 10.9. Look for a 2.5' coma. It should fade slowly, moving into Hydra by month's end. The best visibility is early in the month as seen from the southern hemisphere.  FINDER CHART

Latitude Visibility July 2 Visibility July 9 Visibility July 16 Visibility July 23 Visibility July 30 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 Low in the western sky during evening twilight at ~18:20 Not visible Not visible Not visible Not visible 1-8

C/2021 F1 (Lemmon-PANSTARRS): A southern hemisphere morning comet visible in very large telescopes
This comet begins the month in Eridanus at magnitude 12.5. Look for a 4.5' coma. It should fade by about 1.1 magnitudes, moving into Caelum by month's end. The best visibility is early in the month as seen from the southern hemisphere.  FINDER CHART

Latitude Visibility July 2 Visibility July 9 Visibility July 16 Visibility July 23 Visibility July 30 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 ~04:50 Not visible Not visible Not visible 1-10
30o S High at ~05:30 High at ~05:30 Not visible High in moonlight at ~05:20 High at ~05:20 1-11, 21-

45P/Honda-Mrkos-Pajdusakova: A southern hemisphere evening comet visible in very large telescopes
This comet begins the month in Cancer at magnitude 13.0. Look for a 3' coma. It should fade rapidly, moving into Leo by month's end.  FINDER CHART

Latitude Visibility July 2 Visibility July 9 Visibility July 16 Visibility July 23 Visibility July 30 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 Low in the western sky during evening twilight at ~19:20 Not visible Not visible Not visible Not visible 1-6
30o S Low in the western sky during evening twilight at ~18:30 Not visible Not visible Not visible Not visible 1-5

19P/Borrelly: A northern hemisphere evening comet visible in very large telescopes
This comet begins the month in Leo Minor at magnitude 13.0. Look for a 2' coma. It should fade by about 0.7 magnitudes by month's end.  FINDER CHART

Latitude Visibility July 2 Visibility July 9 Visibility July 16 Visibility July 23 Visibility July 30 Nights Visible
55o N Not visible Not visible Not visible Not visible Not visible  
40o N Low in the western sky during evening twilight at ~21:20 Not visible Low in the western sky during evening twilight at ~21:10 Not visible Not visible 1-8, 14-17
Equator Low in the western sky during evening twilight at ~19:20 Not visible Low in the western sky during evening twilight at ~19:20 Not visible Not visible 1-8, 14-19
30o S Not visible Not visible Not visible Not visible Not visible  

9P/Tempel: A morning comet visible in very large telescopes
This comet begins the month in Aquarius at magnitude 13.2. Look for a 3.5' coma. It should remain constant, moving into Sculptor by month's end. The best visibility is late in the month as seen from the southern hemisphere.  FINDER CHART

Latitude Visibility July 2 Visibility July 9 Visibility July 16 Visibility July 23 Visibility July 30 Nights Visible
55o N Not visible Not visible Not visible Not visible Not visible  
40o N Fairly high in the southern sky during morning twilight at ~02:40 Fairly high in the southern sky during morning twilight at ~02:40 Not visible Fairly high in the southern sky in moonlight at ~02:50 Fairly high in the southern sky at ~02:30 1-11, 20-
Equator High at ~04:20 High at ~04:00 Not visible High at ~02:50 High at ~02:40 1-11, 18-
30o S High at ~04:30 High at ~04:00 Not visible High at ~03:10 High at ~02:40 1-11, 18-

C/2020 V2 (ZTF): A northern hemisphere evening comet visible in very large telescopes
This comet begins the month in Ursa Major at magnitude 13.2. Look for a 1' coma. It should brighten slowly.  FINDER CHART

Latitude Visibility July 2 Visibility July 9 Visibility July 16 Visibility July 23 Visibility July 30 Nights Visible
55o N Fairly high in the northern sky during evening twilight at ~00:00 Fairly high in the northern sky during evening twilight at ~00:00 Fairly high in the northern sky during evening twilight at ~23:50 Fairly high in the northern sky during evening twilight at ~23:50 Fairly high in the northern sky during evening twilight at ~23:30 1-
40o N Fairly high in the northern sky during evening twilight at ~21:30 Fairly high in the northern sky during evening twilight at ~21:20 Fairly high in the northern sky during evening twilight at ~21:20 Fairly high in the northern sky during evening twilight at ~21:10 Low in the northern sky during evening twilight at ~21:00 1-
Equator Low in the northern sky during evening twilight at ~19:20 Low in the northern sky during evening twilight at ~19:10 Very low in the northern sky during evening twilight at ~19:10 Not visible Not visible 1-17
30o S Not visible Not visible Not visible Not visible Not visible  

C/2020 R7 (ATLAS): A southern hemisphere evening comet visible in very large telescopes
This comet begins the month in Pavo at magnitude 13.6. Look for a 1.5' coma. It should remain constant, moving into Ara by month's end. The best visibility is late in the month as seen from the southern hemisphere.  FINDER CHART

Latitude Visibility July 2 Visibility July 9 Visibility July 16 Visibility July 23 Visibility July 30 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 southern sky at ~01:00 Fairly high in the southern sky at ~02:00 Fairly high in the southern sky at ~21:20 Fairly high at ~21:50 Fairly high at ~21:00 1-
30o S High at ~01:00 High at ~03:00 High at ~20:50 High at ~21:50 High at ~21:00 1-

117P/Helin-Roman-Alu: A morning comet visible in very large telescopes
This comet begins the month in Sagittarius at magnitude 13.8. Look for a 1.5' coma. It should fade slowly. The best visibility is early in the month as seen from the southern hemisphere.  FINDER CHART

Latitude Visibility July 2 Visibility July 9 Visibility July 16 Visibility July 23 Visibility July 30 Nights Visible
55o N Not visible Not visible Not visible Not visible Not visible  
40o N Low in the southern sky at ~00:10 Low in the southern sky at ~00:30 Low in the southern sky at ~22:20 Low in the southern sky at ~22:30 Low in the southern sky at ~22:00 1-10, 14-
Equator High at ~00:10 High at ~02:10 High at ~21:20 High at ~22:30 High at ~22:00 1-11, 13-
30o S High at ~00:10 High at ~03:00 High at ~20:50 High at ~22:30 High at ~22:00 1-11, 14-

C/2020 K1 (PANSTARRS): An evening comet visible in very large telescopes
This comet begins the month in Hercules at magnitude 14.0. Look for a 1' coma. It should brighten slowly, moving into Ophiuchus by month's end.  FINDER CHART

Latitude Visibility July 2 Visibility July 9 Visibility July 16 Visibility July 23 Visibility July 30 Nights Visible
55o N High during morning twilight at ~00:00 High during morning twilight at ~00:00 High during evening twilight at ~23:40 Fairly high during evening twilight at ~23:50 Fairly high during evening twilight at ~23:20 1-
40o N High at ~23:20 High at ~00:50 High at ~22:00 High at ~21:40 High at ~21:20 1-
Equator High at ~23:20 Fairly high at ~02:10 High at ~21:20 High at ~21:40 High at ~21:00 1-11, 13-
30o S High at ~23:20 Fairly high in the western sky in moonlight at ~02:20 High at ~20:50 High at ~21:40 High at ~21:00 1-10, 14-

C/2019 U5 (PANSTARRS): An evening comet visible in very large telescopes
This comet begins the month in Canes Venatici at magnitude 14.0. Look for a 55" coma. It should remain constant.  FINDER CHART

Latitude Visibility July 2 Visibility July 9 Visibility July 16 Visibility July 23 Visibility July 30 Nights Visible
55o N Fairly 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 ~23:40 Fairly high in the western sky during evening twilight at ~23:30 Fairly high in the western sky during evening twilight at ~23:00 1-
40o N High at ~21:40 Fairly high in the western sky in moonlight at ~23:50 High at ~21:30 High at ~21:20 Fairly high during evening twilight at ~21:00 1-
Equator High in moonlight at ~19:30 High in moonlight at ~19:30 High at ~19:30 High at ~19:30 High at ~19:30 1-
30o S Fairly high in the northern sky in moonlight at ~19:00 Fairly high in the northern sky in moonlight at ~18:40 Fairly high in the northern sky at ~18:50 Fairly high in the northern sky at ~18:50 Fairly high in the northern sky during evening twilight at ~18:50 1-

116P/Wild: An evening comet visible in very large telescopes
This comet begins the month in Leo at magnitude 14.2. Look for a 60" coma. It should fade slowly, moving into Virgo by month's end.  FINDER CHART

Latitude Visibility July 2 Visibility July 9 Visibility July 16 Visibility July 23 Visibility July 30 Nights Visible
55o N Not visible Not visible Not visible Not visible Not visible  
40o N Low in the western sky during evening twilight at ~21:20 Not visible Not visible Not visible Not visible 1-5
Equator High in moonlight at ~19:30 High during evening twilight at ~19:20 Fairly high at ~19:30 Fairly high at ~19:20 Fairly high in the western sky during evening twilight at ~19:20 1-
30o S High in moonlight at ~18:40 Fairly high during evening twilight at ~18:40 Fairly high at ~18:50 Fairly high at ~18:50 Fairly high at ~18:50 1-

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

July 1st

July 15th

July 31st

 Observations as of (UT)
Mag Diam Mag Diam Mag Diam
C/2017 K2 (PANSTARRS) Ophiuchus 8.7 5.9' 8.5 6.0' 8.3 5.9' 2022 July 1
C/2021 E3 (ZTF) Carina 10.2 4.7' 10.7 4.0' 11.2 3.4' 2022 June 25
C/2021 P4 (ATLAS) Lynx 10.4 2.8' 10.0 2.9' 9.9 2.8' 2022 June 30
C/2019 L3 (ATLAS) Canis Minor 10.9 2.4' 11.0 2.3' 11.1 2.3' 2022 June 2
22P/Kopff Cetus 11.6 5.3' 11.6 5.5' 11.7 5.8' 2022 June 30
C/2021 F1 (Lemmon-PANSTARRS) Eridanus 12.5 4.5' 13.0 4.6' 13.7 4.5' 2022 June 5
C/2019 T4 (ATLAS) Virgo 12.6 1.6' 12.7 1.5' 12.8 1.4' 2022 June 30
45P/Honda-Mrkos-Pajdusakova Cancer 13.0 3.0' 14.3 2.7' 15.7 2.4' 2022 June 9
19P/Borrelly Leo Minor 13.0 2.0' 13.4 1.8' 13.8 1.7' 2022 May 25
9P/Tempel Aquarius 13.2 3.3' 13.1 3.5' 13.1 3.5' 2022 June 9
C/2020 V2 (ZTF) Ursa Major 13.2 1.0' 13.1 1.0' 12.9 1.1' 2022 May 25
C/2020 R7 (ATLAS) Pavo 13.6 1.4' 13.5 1.5' 13.5 1.4' 2022 June 24
117P/Helin-Roman-Alu Sagittarius 13.8 1.3' 13.8 1.3' 13.9 1.3' 2022 June 28
C/2022 E3 (ZTF) Lyra 14.0 54" 13.6 57" 13.3 59" 2022 June 28
C/2019 U5 (PANSTARRS) Canes Venatici 14? 1'? 14? 1'? 14? 52" 2022 March 28
C/2020 K1 (PANSTARRS) Hercules 14.0 1.0' 13.9 1.0' 13.8 1.0' 2022 April 30
116P/Wild Leo 14.2 58" 14.4 55" 14.5 52" 2022 April 29
73P/Schwassmann-Wachmann Leo 14.8 40" 14.3 42" 13.8 45" 2022 June 24
C/2021 A1 (Leonard) Scorpius 14.9 4.1' 15.4 3.5' 16.1 3.0' 2022 April 2
C/2020 Y2 (ATLAS) Columba 15.1 25" 15.2 25" 15.2 25" 2022 May 6
107P/Wilson-Harrington Pisces 15.7 4.5' 15.0 5.1' 14.7 5.0' 2022 June 17
29P/Schwassmann-Wachmann Auriga 15.8 3.6' 15.8 3.6' 15.7 3.7' 2022 April 21
104P/Kowal Sextans 15.8 57" 16.2 52" 16.7 48" 2022 June 2
81P/Wild Gemini 16? 30"? 16? 31"? 15.6? 32"? 2022 March 22
*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 visual observing custom charts for your location and telescope/binoculars: software for visual comet observing 

Select comets that are appropriate for your imaging system, and plan when they are best imaged: 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