Analysis of Comet Apparitions

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Current Fainter Comets of Interest

An asteroidal object of magnitude 22, discovered already on Oct. 20, 2014 by G. Bernstein and P. Bernardinelli with the 4.0m reflector of the Cerro Tololo Interamerican Observatory, displayed cometary activity in mid-June 2021. Comet C/2014 UN₂₇₁ (Bernardellini-Bernstein) showed an 8" coma of total magnitude 19.5, asymmetric towards p.a. 40°. The comet will pass its extremely distant perihelion on Jan. 22, 2031 at the solar distance of 10.95 AU and could then reach magnitude 16-17 (CBET 4983/89).
At the opening of August 2025 the published observations can be plausibly represented by the parameters m₀ ≈ 0.5 mag / n ≈ 3, still showing a large uncertainty and even hinting towards a larger activity parameter. It will certainly take at least additional 2 years until the uncertainty will be significantly reduced. If the comet continues to develop in this way, it can reach a maximum brightness of around 13.5^m. In this case it would be brighter than 16.0^m between mid-2023 and mid-2038. During this period it moves from Hydrus towards Centaurus (perihelion) and thereafter through the constellations Hydra, Corvus, Virgo, Coma Berenices and Canes Venatici. From mid-European locations meaningful observations are possible not before start of 2032.

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An asteroidal object of magntiude 19, which was already discovered on Apr. 21, 2021 by the ATLAS-Team in the constellation Canis Major showed faint cometary signatures during follow-up observations. Until October 2021 additional observations clearly confirmed the cometary nature. Comet C/2021 G2 (ATLAS) will pass perihelion on Sep. 9, 2024 at the solar distance of 4.98 AU, expected to reach magnitude 15.0 in spring 2024 and 2025 (CBET 4988/5057). It should be brighter than 16 mag between November 2023 and August 2025. During this period it moves through the constellations Hydra, Corvus, Virgo and Libra. From mid-European latitudes it will appear in December 2024 above the southeastern morning horizon, and will change into the evening sky in May 2025.

Based on 292 observations from 37 observers the comet showed different developments pre- and post-perihelion, but in every case with an activity parameter slightly above average. The appropriate brightness parameters are:

Total Brightness and Coma Diameter (standard time scale)

Total Brightness and Coma Diameter (compressed time scale)

FGK observations

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An 18 mag asteroidal object, discovered by the ATLAS team on Mar. 7, 2022 in the constellation Antlia showed cometary morphology in the course of follow-up observations. Comet C/2022 E2 (ATLAS) showed a highly condensed 7" coma of total magnitude 18.0, but no tail. The comet will pass perihelion on Sep. 15, 2024 at the solar distance of 3.67 AU, expected to reach magnitude 13 (CBET 5109). It should be brighter than 16 mag between March 2021 and January 2026. During this interval it will move through the constellations Hydra, Cancer, Gemini, Lynx (perihelion), Camelopardalis, Cassiopeia, Lacerta and Pegasus. Thus it will be well-placed for mid-European locations during the most interesting months.

The comet showed different brightness developments pre- and post-perihelion. Whereas the brightness developed on average pre-perihelion, the activity decreased faster than average post-perihelion. Based on 441 observations from 58 observers the appropriate brightness parameters are:

Total Brightness and Coma Diameter (standard time scale)

Total Brightness and Coma Diameter (compressed time scale)

FGK observations

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On July 4, 2022 the PANSTARRS team discovered a comet of magnitude 20 in the constellation Sagittarius. Comet C/2022 N2 (PANSTARRS) showed a condensed 2" coma and a 3" tail in p.a. 260°. It will pass perihelion at the solar distance of 3.84 AU on Aug. 3, 2025, expected to peak at magnitude 14.5 in October/November 2025 (CBET 5148). At discovery it was still at a distance of 9.5 AU from the Sun! Between April 2025 and February 2026 it should be brighter than 16 mag. During this period it moves from central Pisces northeastward to the region near the border of the constellations Aries/Taurus. Thus the observing conditions are optimal for mid-European locations during the time the comet is brightest.

The comet peaked at 13.8 mag at the opening of November 2025, after reaching an initial maximum of 14.9 mag in October 2024. Until the start of February 2026 it had faded to 14.7 mag. Based on 383 observations (mostly per CCD) by 46 observers the following brightness parameters simulate the brightness behavior rather well:

Total Brightness and Coma Diameter (standard time scale)

Total Brightness and Coma Diameter (compressed time scale)

FGK observations

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Comet C/2022 QE₇₈ (ATLAS), which passed perihelion at the solar distance of 5.48 AU on Sep. 10, 2025, became brighter than originally expected, as 195 observations (mostly via CCD) from 30 observers (until the start of February 2026) indicate. Between September 2024 and end of January 2025 the comet brightened from 16.0 mag to a first maximum of 15.1 mag (originally a peak brightness of about 16.5 mag was expected). The brightness development can be well described with the parameters

Total Brightness and Coma Diameter

FGK observations

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On Feb. 1, 2023 the ATLAS team discovered a 19th magnitude asteroidal object near the border of the constellations Centaurus/Vela, which showed cometary morphology in follow-up observations. Comet C/2023 C2 (ATLAS) exhibited a 9" coma of total magnitude 19.0 with a central condensation. The comet will pass perihelion at the solar distance of 2.37 AU on Nov. 16, 2024 and should reach a maximum brightness of 13.5-14.0 mag in August 2024 (CBET 5240). It should be brighter than 16 mag between March 2024 and July 2025. During this period it moves through the constellations Apus, Triangulum Australis, Norma (maximum brightness), Scorpius, Sagittarius (perihelion), Capricornus, Aquarius, Pegasus, Andromeda and Cassiopeia. From central European locations the comet can be sighted just above the southwestern evening horizon between November 2024 (14.0 mag) and January 2025 (14.5 mag) during the first period. It then reappears over the eastern morning horizon in March 2025 (15.0 mag), slowly gaining altitude during the following months, thereby steadily fading.

This comet showed a very continuous brightness development, based on 105 observations from 25 observers. The estimates can be rather well represented by the brightness parameters

Total Brightness and Coma Diameter

FGK observations

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The PANSTARRS team discovered another comet on Sep. 7, 2023 near the border of the constellations Pisces/Andromeda. Comet C/2023 R1 (PANSTARRS) showed a 1.5" coma of total magnitude 19.5. It will not pass its mid-distance perihelion at the solar distance of 3.57 AU until Apr. 14, 2026 (then expected to be of magnitude 15) and should peak at 14 mag in June 2026 (CBET 5293). It should be brighter than 16 mag between July 2025 and October 2026, when it will move through the constellations Pegasus, Vulpecula, Sagitta, Aquila (perihelion), Scutum, Serpens Cauda, Ophiuchus, (maximum brightness), Serpens Caput and Libra. From Central European locations it can be followed until September 2026 - with the exception of the period from mid-December 2025 to the end of January 2026.

It seems that the comet is developing more slowly than expected. Based on 83 observations (mostly by CCD) from 21 observers (until the start of February 2026) the brightness parameters are roughly

Total Brightness and Coma Diameter

FGK observations

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On May 6, 2024 the ATLAS team discovered a comet near the border of the constellations Sagittarius/Corona Australis. Comet C/2024 J3 (ATLAS) showed a highly condensed 9" coma of total magnitude 17.5 and a 12" tail in p.a. 220°. This comet will not pass perihelion at the solar distance of 3.86 AU until Nov. 24, 2026, expected to reach magnitude 13.0 (CBET 5398). It should be brighter than 16 mag between April 2025 and May 2028. During this period it will pass through the constellations Sagittarius, Scutum, Aquila, Delphinus, Vulpecula, Cygnus, Lyra (perihelion), Cygnus, Cepheus, Cassiopeia, Camelopardalis and Auriga. From Central European locations it should be observable from April to November 2025 (first in the morning sky, at the end in the evening sky), and then continuously from February 2026 to May 2028. The Earth will cross the comet's orbital plane every Jan. 7 and July 8.

Based on 49 CCD observations from 9 observers (until the start of February 2026) the comet shows a steady development so far, which can be well described by the parameters
m₀ = 3.7 mag / n = 4.5
Thus it should reach a maximum brightness of 13.0 mag in August 2026. However, the variance in the solar distance is still very small, resulting in a greater uncertainty of the parameter values. The comet currently shows a coma diameter of 0.5' (100,000 km).

Total Brightness and Coma Diameter

FGK observations

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An asteroidal object of 19th magnitude, discovered by the ATLAS project on Oct. 2, 2024 near the border of the constellations Phoenix/Eridanus, revealed its cometary nature during follow-up observations. Comet C/2024 T5 (ATLAS) showed a stellar central condensation surrounded by an extremely diffuse 11" coma of total brightness 18.5 mag. The comet will not pass perihelion at the solar distance of 3.85 AU until May 7, 2027. It could reach 14.0 mag at the turn of the years 2026/27 (CBET 5472). Between May 2026 and May 2028 the comet should be brighter than 16 mag. During this period it will move through the constellations Eridanus, Lepus, Orion, Taurus (perihelion), Gemini, Cancer, Lynx and Ursa Major. For Central European locations it will appear in the morning sky in September 2026 and disappear from the evening sky in April 2027. The second apparition begins in August 2027. Thereafter the comet can be easily tracked until it fades below 16 mag.

At the beginning of February 2026 43 observations from 7 observers can be used for a rough analysis. These indicate a very positive development, which can be described with the parameters
m₀ = 2.0 mag / n = 5.
This implies a peak brightness of 12.0 mag in mid-January 2027. However, it must be expected that additional observations will tend to reduce the large value of the activity parameter. In spring 2026 the comet was of magnitude 15.0. The diameter of the moderately condensed (DC 4) coma measures currently 0.5' (125,000 km).

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On May 23, 2025 the PANSTARRS project discovered a comet near the border of the constellations Cygnus/Draco. Comet C/2025 K3 (PANSTARRS) showed a strongly condensed coma measuring only 1" with total magnitude 21.0 and a 2" tail in p.a. 170°. The comet will not pass perihelion at the solar distance of 3.46 AU until Dec. 14, 2028. It should reach 15.5 mag in spring 2028 and peak at 14.0 mag in February 2029 (CBET 5564). It should be brighter than 16 mag between February 2028 and August 2029. During this period it will move through the constellations Bootes, Canes Venatici, Ursa Major, Leo, Virgo, Crater (perihelion), Hydra (maximum brightness) and Pyxis. From Central European locations it can initially be observed at high altitudes throughout the night, but will disappear above the western evening horizon in July. At the end of October 2028 it reappears in the morning sky at significantly lower altitudes and can then be followed at low altitudes until the end of April 2029.

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On June 6, 2025 the ATLAS team discovered a comet near the border of the constellations Eridanus/Horologium. Comet C/2025 L1 (ATLAS) exhibited a highly condensed, 1.5" coma with total magnitude 18.0 and a faint, 3" tail in p.a. 300°. It will pass perihelion at the solar distance of 1.68 AU on Jan. 12, 2026 and should reach a peak brightness of 14.0 mag in March 2026 (CBET 5566). It should be brighter than 16 mag from October 2025 to May 2026. During this period it will pass through the constellations Centaurus, Lupus (perihelion), Scorpius, Libra, Serpens (maximum brightness), Bootes and Canes Venatici. From Central European locations it will appear in the morning sky at the beginning of February 2029, thereafter quickly gaining high altitudes.

At perihelion the comet reached a brightness of 14.5-15.0 mag; the coma diameter was determined to be 0.5'. Until the end of March it will approach Earth (to within 1.10 AU) and could therefore become a little brighter during the next weeks.

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On June 22, 2025 the PANSTARRS team discovered a 19th magnitude comet in the constellation Capricornus. Comet C/2025 M2 (PANSTARRS) showed a strongly condensed coma measuring just 1.5". It will pass perihelion on Nov. 26, 2027 at a solar distance of 2.73 AU and could reach a maximum brightness of about 12.5 mag in March 2028 (CBET 5576). It would be brighter than 16 mag between January 2027 and February 2029, during which time it will pass through the constellations Sagittarius, Scorpius, Libra, Virgo (perihelion and maximum brightness), Leo and Cancer. From Central European locations it can be followed between March and August 2027, between December 2027 and May 2028 and finally between September 2028 and February 2029.

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On Sep. 8, 2025, the PANSTARRS team discovered an additional comet, this time in the constellation Andromeda. Comet C/2025 R3 (PANSTARRS) showed a condensed 5" coma of total magnitude 19.5 and a broad 10" tail in p.a. 165-225°. The comet will pass perihelion at a solar distance of 0.50 AU on Apr. 19, 2026, expected to peak at 9 mag if it shows an average development (CBET 5607). It is expected to be brighter than 16 mag between February and June 2026. During this period it will move through the constellations Pegasus, Pisces (perihelion), Cetus, Taurus, Eridanus, Orion, Monoceros, and Canis Major. From Central European locations the comet can only be observed in the evening sky until mid-February 2026 and just above the eastern horizon in the morning sky between early March and mid-April. However, the absolute magnitude, as derived from published observations, is 2 mag below the Bortle-limit. Thus there is a certain probability that the comet will disintegrate on its way to the Sun. If the comet survives its perihelion without major damage, J. Marcus' formulae predict that there will be significant forward scattering in the second half of April, which could increase its brightness by up to 6.5 mag on Apr. 26! However, the comet will only be 5° from the Sun on that day. Earth will cross the comet's orbital plane on Apr. 29.

At the start of February 2006 the comet's development is still extremely uncertain. The few observations published so far indicate an absolute magnitude 2 mag higher than previously assumed. Nevertheless, the absolute brightness remains below the Bortle limit, albeit only just. Thus, the probability that the comet will disintegrate on its way toward the Sun or shortly after perihelion is quite high. The published observations indicate magnitudes of about 13.5 for early February 2026. Thus the resulting brightness parameters are very roughly
m₀ = 10.0 mag / n = 3.
Applying these parameters the comet should be of magnitude about 7.5 at perihelion, 6.5 mag on Apr. 26, and 9.0 mag in mid-May. In combination with the forward scattering the comet could thus reach a maximum brightness of roughly 0 mag on Apr. 26! But only if it survives the perihelion passage unscathed. On the day of maximum forward scattering, however, the comet rises after the Sun in the morning and sets before the Sun in the evening for locations in Central Europe.

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On Nov. 2, 2025, Gennadii Borisov discovered a comet near the border of the constellations Virgo/Crater, showing a 0.5' coma, for which he reported a total magnitude of 12.1. Follow-up observations of comet C/2025 V1 (Borisov) showed a strongly condensed coma up to 4' in size with a total magnitude of 10.5, but no tail. The comet will pass perihelion on Nov. 16, 2025, at a solar distance of only 0.46 AU and could then become as bright as 9.5 mag (CBET 5631). However, the determined absolute brightness is well below the Bortle limit, so there is a high probability that it will disintegrate on its way to perihelion. If it survives the perihelion passage it would be brighter than 16 mag until mid-January 2026. During this period it will move through the constellations Virgo, Serpens, Ophiuchus, Serpens, Scutum, and Aquila. From Central European locations it could only be seen low above the eastern morning horizon until mid-November and then low above the western evening horizon between mid-November and mid-December.
The comet did not reach perihelion. Images taken on Nov. 5 already showed it to be significantly fainter, and by Nov. 7 it was barely detectable. It was probably discovered during an outburst, as it appears about 5 mag fainter in pre-discovery images taken a few days before discovery. According to Michael Jäger the comet appeared 3 mag fainter on Nov. 8 than on Nov. 4 (Comet's Mailing List).

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On Nov. 2, 2025, David Rankin of the Lunar and Planetary Laboratory discovered a comet of magnitude 19.5 in the eastern part of the constellation Leo. Comet C/2025 V2 (Rankin) showed a strongly condensed 5" coma, but no tail. The comet will not pass perihelion at a solar distance of 1.95 AU until March 23, 2027, and should reach a maximum brightness of 13.5 mag in May 2027. It should be brighter than 16 mag between October 2026 and October 2027. During this period it will move through the constellations Coma Berenices, Bootes, Serpens, Hercules/Ophiuchus (perihelion), Sagitta (maximum brightness), Aquila and Sagittarius. From Central European locations it can be observed in the morning sky between November 2026 and June 2027. Thereafter it will initially be observable throughout the night and will eventually end its visibility in the evening sky. The Earth will cross comet's orbital plane on Feb. 7 and Aug. 11, 2027.

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On Jan. 19, 2026, Chinese observers Guoyou Sun and Xing Gao discovered a comet near the border of the constellations Serpens and Aquila during their search program concerning comets near the Sun, using telescopes at the Xingming Observatory. Comet C/2026 B2 (Sun-Gao) showed as an object of magnitude 15 with a 15" coma, but no tail. Follow-up observations by various observers showed a coma up to 1.0' in size of total magnitude 14.7, exhibiting a central condensation. The comet passed perihelion at a solar distance of 1.28 AU on Jan. 10, 2026. Unfortunately it was then positioned on the far-side of the Sun. It was probably discovered at the time of maximum brightness (CBET 5660). Assuming an average brightness development the comet should remain brighter than 16 mag until mid-March. During this period it will move through the constellations Aquila, Delphinus, Vulpecula and Pegasus. From Central European locations it can be observed low in the morning sky during this period.
Only a very small number of observations have been published until early February 2026. These suggest an outburst, but this assumption must be confirmed by additional observations.

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Comet 10P/Tempel (P=5.36a) will pass perihelion on Aug. 2, 2026, at a solar distance of 1.42 AU. It is expected to become brighter than 16 mag in March/April. Until mid-May it will move from the constellation Serpens to the constellation Aquila. The comet has an absolute magnitude of 7.0-8.0 mag and a high activity parameter (n = 10-12). It should reach magnitude 13 in mid-May.

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Comet 47P/Ashbrook-Jackson (P=8.36a) will pass perihelion at the solar distance of 2.81 AU on Oct. 27, 2025, but should reach its maximum brightness of 14.5 mag as early as September. For mid-European locations the comet will appear in the morning sky at the beginning of July.

Total Brightness and Coma Diameter

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Comet 65P/Gunn (P=7.68a) will pass perihelion at a solar distance of 2.93 AU on June 16, 2025 and could then reach a maximum brightness of around 15.0-15.5 mag. It is positioned in the southern part of the constellation Sagittarius, so it will be a very difficult object for mid-European locations.
Less than 20 CCD observations can I use for a very preliminary analysis at the opening of August 2025. The brightness estimates can be represented reasonably well with the brightness parameters
m₀ = 9.0 mag / n = 4.
Thus the comet reached a maximum brightness of about 15.0 mag in July 2025, and should become fainter than 16.0 mag already in October. The coma diameter measured about 0.5'.

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Comet 88P/Howell (P=5.48a) will pass perihelion at a solar distance of 1.36 AU on March 18, 2026. Unfortunately it will be close to the Sun for many weeks and cannot be seen from mid-European locations. Until the beginning of February 2026 only a few observations have been reported. These indicate a brightness of about 12.5 mag and a coma diameter of about 0.5' at the beginning of February, which is significantly fainter than the predictions. It must therefore be expected that the comet will reach a maximum brightness of only 11.0-12.0 mag.

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On Nov. 22, 2025 comet 210P/Christensen (P=5.62a) will once again pass perihelion at the solar distance of 0.52 AU.

Only 49 observations (mostly by CCD) from 16 observers can be used for the analysis at the beginning of February 2026. These show a significantly more rapid increase in activity pre-perihelion than the decrease post-perihelion. The maximum brightness of 9.8 mag was reached around Nov. 20, 2025, although the observed maximum brightnesses pre-perihelion were 11.7 mag (on Nov. 1) and 10.3 mag (on Nov. 28) post-perihelion. At the end of September 2025 the comet was of magnitude 17.0 and at the beginning of February 2026 of magnitude 15.0. The corresponding brightness parameters are:

pre-perihelion:   m₀ = 16.5 mag / n = 7.5
post-perihelion: m₀ = 13.3 mag / n = 3.0

Total Brightness and Coma Diameter

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Comet 235P/LINEAR (P=6.40a) passed perihelion on Dec. 22, 2025, at a solar distance of 1.98 AU, significantly brighter than expected. The comet can be seen in the morning sky in spring 2026. It will move from the constellation Scorpius to the border of the constellations Ophiuchus/Serpens. On Apr. 11 Earth crosses the comet's orbital plane.

Based on only 26 observations (mostly by CCD) from 13 observers a very rough analysis can be done at the beginning of February 2026. While there are too few observations for the pre-perihelion period, the post-perihelion brightness development can be well represented by the formula
m = 11.7 mag + 5×log D + 0.020×|t - T|
This yields a maximum brightness of 13.6 mag on the Christmas Days 2025. Between mid-February and mid-May 2026 the comet is expected to fade from 14.0 mag to 15.0 mag. The diameter of the significantly condensed (DC 5) coma reached a maximum of 1.0' (110,000 km) in January 2026. A tail of maximum length 3' (800,000 km) was directed towards the West.

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Comet 240P/NEAT (P=7.59a) will pass perihelion at the solar distance of 2.12 AU on Dec. 19, 2025 and will be in opposition to the Sun at this time, near the border of the constellations Taurus and Aries.

The comet showed a surprisingly complex brightness behavior, as evidenced by 383 observations (mostly by CCD) from 43 observers (until early February 2026). Furthermore, the observations can only be meaningfully simulated with time-dependent formulae. In mid-July 2025 and early February 2026 the comet was only of magnitude 15.0, peaking at 11.8 mag on Dec. 10, 2025. It was not until 80 days before perihelion that the heliocentric brightness began to increase. The decline post-perihelion was more rapid than the increase in activity pre-perihelion. The brightness development can be represented as follows:

Total Brightness and Coma Diameter (Main Component)

FGK observations (Main Component)

Total Brightness and Coma Diameter of Fragment B

Andreas Kammerer