Comet Chasing in May

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

There is one comet visible in binoculars and one visible in a six-inch telescope, but neither is visible from the northern hemisphere this month. See the Observing Synopses for which comets are visible from your latitude, the best dates and the time of night.

• C/2025 R3 (PANSTARRS) will reach perihelion on April 19. On April 19 this comet will pass within 0.5 AU of the earth. It is predicted to reach maximum brightness of magnitude 0 in late April and will likely be visible to the naked eye..

• 29P/Schwassmann-Wachmann has frequent outbursts, typically resulting in a brightening of 1 - 4.0 magnitudes. 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. See Mission 29P from the BAA for up to date information. 

• 88P/Howell is a periodic comet with an orbitl period of 5..5 years. I passed perihelion in March 2026 at a distance of 1.4 AU.

• 10P/Tempel is a periodic comet with an orbital period of 5.4 years. Perihelion is on August 2, 2026 at a distance of 1.4 AU.

• C/2024 E1 (Wierzchos) passed perihelion on January 20 2026. 

• 24P/Schuamasse is a periodoc comet with an 8.2 year orbital period. Perihelion was on January 8, 2026. 

• C/2025 A6 (Lemmon) is an amazing comet that brightened quickly in late August and became a naked eye object in October and November. There were reports of fans, streamers, and other structures apparent in the eyepiece at high magnification. It is now on its way out.

• C/2025 T1 (ATLAS) passed perihelion in early December. It reached maximum brightness of magnitude 11.2 in mid November. 

• C/2025 K1 (ATLAS) fragmented, splitting into at least three parts (November 10). It has since faded. This comet was discovered on May 24. It passed perihelion  on October 8. 

• 240P/NEAT is a periodic comet with a 7.6 year orbital period. Perihelion was on December 19. It split into a second, fainter component (240P-B) in October. 

• 235P/LINEAR is a periodic comet with a 6.4 year orbital period. Perihelion was on December 22 at a distance of 2.0 AU. It is currently predicted to reach maximum brightness of magnitude 12.5 in late April 2026.

• 210P/Christensen is a periodic comet with a 5.6 year orbital period. Perihelion is on November 22, when it will also be within 0.5 AU of the earth. 

• C/2025 R2 (SWAN) was identified by Vladimir Bezugly in SWAN images around 2025-09-11 (visible in SWAN since at least Sep 4, with STEREO-A/HI-1 detections into late August. C/2025 R2 (SWAN) is past perihelion, which occurred in mid September 2025. On September 12 this comet passed within 0.3 AU of the earth. It reached maximum brightness in late September

• C/2021 G2 (ATLAS) is past perihelion, which occurred in early September 2024. It reached maximum brightness of magnitude 14 in late August.

• 3I/ATLAS is the 3rd interstellar comet. It is on it way out of the solar system, and fading rapidly. It passed closest to the sun on October 29 at a distance of 1.4 AU. 

• C/2026 A1 (MAPS) has apparently disintegrated (see below for more info).  It reached perihelion on April 4 at a distance of just 0.005 AU. This was a Kreutz sungrazer comet; possbly a fragment of the Great Comet of 1106. C/2014 UN271 (Bernardinelli-Bernstein) is an interesting Oort cloud comet that was 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. HST observations that isolate the nucleus estimate the diameter to be 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 disintegrated: C/2026 A1 (MAPS), C/2025 F2, C/2024 G3, C/2024 S1 (ATLAS), C/2022 S3 (PANSTARRS), C/2021 P4 (ATLAS), C/2020 Q1 (Borisov), C/2020 P1 (NEOWISE), and C/2019 Y4 (ATLAS). Beware that various sources often fail to keep track of whether or not a comet still exists!

Comet Visibility in the Eyepiece

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. 

This page uses code developed for SkyTools to predict the visibility of a comet.  Predicting how much aperture is required to see a comet is a very complex task. The magnitude alone is a very poor predictor.  SkyTools considers the magnitude, coma diameter, and degree of concentration of the comet, based on recent observations.The predictions are made for a Country/Suburban site, which is approximately Bortle 5, unless indicated otherwise. 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 May