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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 13.5m. In this case it would be brighter than 16.0m 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 287 observations from 36 observers the comet shows different developments pre- and post-perihelion, but in every case with an activity parameter above average. The appropriate brightness parameters are:
pre-perihelion : m0 = 2.8 mag / n = 4.5 post-perihelion: m0 = 1.4 mag / n = 5.0 Thus the comet reached its peak brightness of about 13.5 mag at the beginning of May 2025, after it had already become 13.9 mag bright at the end of April 2024. By the end of September 2025 the comet had faded to 15.0 mag.Total Brightness and Coma Diameter (standard time scale)
Total Brightness and Coma Diameter (compressed time scale)
After the coma diameter increased from 0.6' (130,000 km) at the beginning of 2024 to 1.1' (210,000 km) in April, it decreased to 0.6' (175,000 km) by the end of August. After perihelion the apparent coma diameter increased from 0.8' to the maximum of 1.4' (May 2025), thereafter decreasing to 0.8' by the end of September. Post-perihelion the absolute coma diameter increased from 200,000 km to the maximum of 250,000 km, thereafter decreasing to 225,000 km at the end of September. The degree of condensation increased from DC 4-5 at the beginning of 2024 to DC 6 in May 2024. Until spring 2025 it had decreased to DC 3-4. A tail, pointing constantly in westerly directions, was observed throughout the entire apparition. It was 3' (4 mio. km) long in 2024 and showed a length of 9' (12 mio. km) in 2025.--------------------
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:
pre-perihelion: m0 = 6.4 mag / n = 2.8Total Brightness and Coma Diameter (standard time scale)
Total Brightness and Coma Diameter (compressed time scale)
The coma diameter measured 0.4' for many months, but starting in October 2023 it increased noticeably, reaching 1.3' at the beginning of February 2024. After decreasing, due to a temporary increase in the distance to Earth, it again increased, reaching 1.4' at maximum in November 2024. At the end of October 2025 it measured 0.7'. The absolute coma diameter measured 100,000 km during the first months. Thereafter it constantly measured 175,000 km, but shrunk to 130,000 km in October 2025. In 2024 the coma showed a constant degree of condensation of DC 4-5. At the start of 2025 DC 3 was reported. Since the start of the apparition a tail can be detected, which reached a length of 8' (6 mio. km) in winter 2024/25. Most of the apparition the tail was oriented towards East to Southeast. In winter 2024/25 it turned from Southeast towards ENE.--------------------
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 probably reached its maximum brightness of 14.0 mag in mid-November 2025, after reaching an initial maximum of 15.1 mag in October 2024. Based on 219 observations (mostly per CCD) by 38 observers the brightness parameters are:
m0=8.4 mag / n=2.3.Total Brightness and Coma Diameter
The apparent diameter of the rather diffuse coma (constant DC 2-3) increased from 0.4' at the beginning of visibility to 0.7' in the fall of 2024. From August to the end of September 2025 it increased from 0.7' to 1.2', but seems to have been slowly decreasing again since then. Thus, the absolute coma diameter increased only slightly from 135,000 km to 150,000 km. A tail pointing constantly toward the WSW could be detected on CCD images throughout the entire apparition, reaching a maximum length of 6' (5 mio. km) shortly after perihelion.--------------------
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 109 observations (mostly via CCD) from 18 observers (until the start of November 2025) 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 described in a plausible manner with the parameters
m0=0.3 mag / n=6. Thus the comet should reach main maximum of 14.8 mag in mid-January 2026. The medium-condensed (DC 3-4) coma reached a diameter of 0.6' (140,000 km) in late winter 2024/25. CCD observers document a short tail since the turn of 2024/25.Total Brightness and Coma Diameter
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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
m0 = 8.6 mag / n = 3. It reached peak magnitude of 13.5 in August 2024. Until December 2024 it had faded to 14.0 mag, until mid-October 2025 to 16.0 mag.Total Brightness and Coma Diameter
The coma diameter increased from 0.4' (50,000 km) at the start of the apparition to 0.8' (75,000 km) at the end of August 2024. The degree of condensation was constant at about DC 4. In summer 2025 the comet showed a well-condensed (DC 5) coma of 0.7' (100,000 km), in fall of 0.5' (75,000 km) diameter. CCD-observers detected a tail of up to 1' (700,000 km) length, which was oriented towards West until the beginning of July 2024, thereafter towards Southeast.--------------------
Comet C/2023 Q1 (PANSTARRS), which passed perihelion on Dec. 1, 2024 in the solar distance of 2.58 AU, became brighter than expected (originally a maximum brightness of 16.0 mag in December 2024 was predicted). Based on 65 observations (mainly per CCD) from 16 observers the brightness development can be represented quite well with the parameters
m0 = 11.9 mag / n = 2.5.
Thus the comet reached a maximum brightness of 14.9 mag in December 2024. The medium-condensed coma reached a maximum diameter of 0.7' (55,000 km). The observers recognized a very short, westward pointing tail.
Total Brightness and Coma Diameter
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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.
Until the start of November 2025 the comet shows a very steady brightness development. Based on 79 observations (mostly via CCD) from 21 observers the brightness parameters can be roughly determined as
m0 = 8.2 mag / n = 3. This means that the comet should reach a maximum brightness of around 14.5 mag in mid-June 2026. Currently the diameter of the significantly condensed (DC 5) coma measures about 0.6' (90,000 km). On CCD images a short, East oriented tail can be detected.Total Brightness and Coma Diameter
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Comet P/2023 S1 (PANSTARRS) (P=7.54a) became 1.5 mag brighter than expected. Originally a maximum brightness of 16.5 mag had been predicted.
The brightness development can be represented reasonably well with a classic log r - formula (albeit with extremely high parameter values), but much better with a time-dependent |t-T|-formula. Therefore, both formulas are noted in the diagram. The total of 73 observations (mainly by CCD) from 16 observers yield the following brightness parameters:
log r - formula: m0 = -12.5m / n = 25
|t-T| - formula: pre-perihelion : m0 = 13.4m / nt = 0.009
post-perihelion: m0 = 13.4m / nt = 0.018
The maximum brightness of 14.6 mag was reached at the end of February 2025.
Total Brightness and Coma Diameter
The moderately condensed coma reached a maximum diameter of 0.8' at the beginning of February, which corresponds to 60,000 km. A tail pointing to the WNW could be detected. In April 2025 the comet became fainter than 16 mag.--------------------
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 48 CCD observations from 9 observers (until the start of November 2025) the comet has shown a very steady development so far, which can be well described by the parameters
m0 = 4.5 mag / n = 4
Thus it should reach a maximum brightness of 13.2 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
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On June 29, 2024 the ATLAS team discovered an asteroidal object of magnitude 18 in the constellation Caelum, which showed a cometary morphology during follow-up observations. Comet C/2024 M1 (ATLAS) exhibited a highly condensed 8" coma and a 6" tail in p.a. 240°. On images taken by the 4m reflector of the Cerro Tololo Observatory on May 10, 2022 it appeared stellar. The comet will pass perihelion at the solar distance of 1.70 AU on Nov. 20, 2024, expected to reach magnitude 13.5-14.0 (CBET 5419). It should be brighter than 16 mag between mid-September 2024 and mid-February 2025. During this period it will move through the constellations Canis Major, Monoceros, Orion (perihelion), Taurus, Perseus and Andromeda. From Central European locations it will initially be a morning object at low altitudes, but starting in November it will become an all-night object, reaching ever greater altitudes. Finally, it will get fainter than 16 mag in the evening sky at high altitudes. The Earth will cross the comet's orbital plane on Dec. 8.
The comet remained a little fainter than expected, as shown by 79 CCD observations from 20 observers. The brightness development can be represented reasonably well with the parameters
m0 = 11.8 mag / n = 6,
yielding a peak brightness of 14.5 mag at the beginning of December 2024. Although the comet came quite close to Earth the coma diameter did not exceed 0.4', which corresponds to an absolute diameter of just 13,000 km! The coma was extremely condensed (DC 8-9). A tail was not observed. At the beginning of 2025 it faded below 16.0 mag.
Total Brightness and Coma Diameter
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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.
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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.
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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.
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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.
The comet reached a maximum brightness of 15.5 mag in mid-September 2025, based on 46 CCD observations from 11 observers. The brightness parameters can be roughly deduced as: m0 = 5.2 mag / n = 8. However, the variance in the distance to the Sun over the apparition is very small, resulting in large uncertainties concerning the parameter values (for example, the parameters m0 = –1.5 mag / n = 14 give a very similar result!). The coma diameter reached a maximum of 0.6' (50,000 km). A tail pointing towards WSW with a maximum length of 3' (1.5 million km) was detected.Total Brightness and Coma Diameter
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Comet 49P/Arend-Rigaux (P=6.74a) can be observed in the evening sky with large instruments until the end of April 2025. Thereafter it is too near the Sun for reasonable observations. It moves from the constellation Cetus into Taurus. The comet passes perihelion at the solar distance of 1.43 AU on Apr. 10, 2025.
The comet became somewhat brighter than expected and reached a maximum brightness of 13.8 mag at the beginning of April 2025, after having been only about 18 mag in mid-December 2024. On the basis of only 17 CCD observations the brightness development can be represented reasonably well with the parametersTotal 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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On Nov. 22, 2025 comet 210P/Christensen (P=5.62a) will once again pass perihelion at the solar distance of 0.52 AU. So far only 20 CCD observations can be used for a very preliminary analysis. These can be reasonably well represented by the parameters
m0=16.5 mag / n=5,
indicating a maximum brightness of 11.5 mag in mid-November 2025. At the beginning of November 2025 it was of magnitude 12.0, showing a moderately condensed (DC 4) coma of about 1' in diameter. Starting in December 2025 the comet will appear in the morning sky, but is expected to fade rapidly in the following weeks. It is moving eastward through the constellation Libra. The Earth will cross the comet's orbital plane on December 25.
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Comet 217P/LINEAR (P=7.83a) passed perihelion at the solar distance of 1.23 AU on May 24, 2025, but was quite close to the Sun for a long time. Starting in mid-August 2025 the comet can be seen in the morning sky from mid-European locations, but should already become fainter than 16.0 mag in November. During this period it moves from the southwestern part of the constellation Gemini to the eastern part of the constellation Cancer.
Due to the unfavorable conditions it is no wonder that just 25 CCD observations can be used for a very preliminary analysis. These can be simulated reasonably well with the brightness parameters
m0=10.0 mag / n=5.
The comet peaked at 12.5 mag at the end of June 2025. The diameter of the medium-condensed coma reached 0.7'. A short appendage towards West could be documented.
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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.
Despite its relative faintness the comet is been observed quite intensively. At the start of November 2025 108 observations (mostly by CCD) from 24 observers can be used. The brightness estimates can be represented quite well with the brightness parameters
m0=10.8 mag / n=2.3, which indicates a maximum brightness of 13.0 mag at the end of November 2025. Until now the apparent coma diameter increased from 0.6' to 1.5', corresponding to a constant absolute coma diameter of 80,000 km. The coma is rather diffuse with a degree of condensation of DC 3. The CCD images consistently show a tail pointing almost exactly towards West, which reached a length of 7' (1.5 mio. km) at the beginning of November 2025.Total Brightness and Coma Diameter
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Comet 496P/Hill (P=15.07a) = P/2010 A3 (Hill), which passed perihelion at a solar distance of 1.62 AU on March 10, 2025, reached a maximum brightness of about 15.0-15.5 mag at the end of March 2025. At the beginning of May it became fainter than 16 mag. The diameter of the moderately condensed coma reached about 1.5' (200,000 km).
Andreas Kammerer
