Home=Current Comets: Fainter Comets
| The German Group
| Tutorials
| Archive
| Projects, publications
| Images
| Contact
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.
Until the start of February 2025 the comet shows a very steady brightness development according to the parameters
m0 = 2.7 mag / n = 4.5,
based on 114 observations from 11 observers. Thus the comet peaked at magnitude 13.8 in mid-April 2024 and should show a secondary maximum of 14.0 mag at the end of April 2025 (the small fading is caused by the temporary increase of the distance to Earth). After the coma diameter increased from 0.6' (130,000 km) at the beginning of 2024 to the maximum of 1.1' (210,000 km) in April, it decreased to 0.6' (175,000 km) by the end of August. At the beginning of 2025 it measured 0.8' (195,000 km). The degree of condensation increased from DC 4-5 at the beginning of 2024 to DC 6 in May 2024. At the opening of 2025 DC 4-5 is reported. A tail with a maximum length of 3' (4 mio. km), pointing constantly in a westerly direction, was observed throughout the entire apparition.
Total Brightness and Coma Diameter
--------------------
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 shows a fairly steady brightness development, as demonstrated by 344 observations from 48 observers (until the start of February 2025). This can be represented moderately well with the parameters
m0 = 6.7 mag / n = 2.6.
This results in a first maximum of 13.2 mag in mid-February 2024 and a peak brightness of 12.8 mag at the end of November 2024. The coma diameter measured 0.4' for many months, but starting in October 2023 it increased noticeably, reaching 1.2' at the beginning of February 2024. After decreasing, due to a temporary increase in the Earth distance, it again increased, reaching a second maximum of 1.2' in November 2024. At the beginning of 2025 it measured 0.7'. The absolute coma diameter measured 100,000 km during the first months. Since then it constantly measures 170,000 km. In 2024 the coma showed a constant degree of condensation of DC 4-5. At the start of 2025 DC 3-4 is reported. Since the start of the apparition a tail can be detected, which reached a length of 7' (5 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.
Total Brightness and Coma Diameter (standard time scale)
Total Brightness and Coma Diameter (compressed time scale)
--------------------
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.
Based on 103 observations by 22 observers (until start of February 2025), the brightness development can be represented with the parameters
m0=3.8 mag / n=5,
indicating a maximum brightness of 13.5 mag in October 2025. The diameter of the medium-condensed (DC 4) coma increased from 0.4' (85,000 km) at the start of the apparition to 0.8' (140,000 km) in October 2024. Because of the temporarily increasing distance to Earth the coma diameter decreased to 0.6' (140,000 km) until the start of 2025. Since the start of the apparition a tail of maximum length 2' (2 mio. km), pointing constantly towards SW, is detectable.
Total Brightness and Coma Diameter
--------------------
Comet C/2022 QE78 (ATLAS), which will pass perihelion at the solar distance of 5.48 AU on Sep. 10, 2025, became brighter than originally expected, as 69 observations (mostly via CCD) from 14 observers indicate. Between September 2024 and January 2025 the comet brightened from 16.0 mag to 15.0 mag (originally a peak brightness of about 16.5 mag was expected). The development can be described quite well with the parameters
m0=0.3 mag / n=6.
If additional observations should these parameters confirm the comet will reach a first maximum of 15.1 mag at the end of January 2025 and the primary maximum of about 14.7 mag in January 2026. So far the coma diameter measured 0.5' (125,000 km).
Total Brightness and Coma Diameter
--------------------
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 56 observations from 9 observers. The estimates can be rather well represented by the brightness parameters
m0 = 9.3 mag / n = 2.5.
It reached peak magnitude of 13.5 in August 2024. Until December 2024 it had faded to 14.0 mag. 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. So far the degree of condensation is constant at about DC 4. CCD-observers detect a tail of up to 1' (700,000 km) length, which was oriented towards West until the beginning of July, thereafter towards Southeast.
Total Brightness and Coma Diameter
--------------------
Comet C/2023 Q1 (PANSTARRS) became brighter than expected (originally a maximum brightness of 16.0 mag in December 2024 was predicted). Based on 44 observations from 14 observers an unusual brightness development is indicated. The heliocentric magnitude seems to increase further even after perihelion passage. So far the brightness development can be best represented with a time-dependent approach:
m0 = 14.3 mag / nt = -0.015.
If this development should be confirmed the comet would not reach maximum brightness of about 14.5 mag until spring 2025. In winter 2024/25 the coma diameter measured 0.6' (55,000 km). At mid-European locations the comet will be observable in the evening sky until mid-May. It moves from the eastern part of the constellation Orion to the southwestern part of the constellation Gemini. The brightness should increase from 15.0 mag to 14.5 mag.
--------------------
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.
--------------------
The still unnamed comet P/2023 S1 (P=7.54a) became also brighter than expected. Originally a maximum brightness of 16.5 mag had been predicted. Based on 35 observations by 10 observers an extremely steep brightening is indicated, which can be represented reasonably well with the parameters
m0 = -2.7 mag / n = 16.
Thus the comet should reach maximum brightness around 15.0 mag at the beginning of February 2025. In winter 2024/25 the coma measured 0.8'. In spring 2025 the comet moves slowly through the constellation Cancer, making it an object in the night or evening sky. The comet should fade to 16.0 mag by the end of April.
--------------------
On their images taken on Nov. 5, 2023 with two 28cm-SC and CMOS cameras at the Hakos Astrofarm, the Spanish amateur Jordi Camarasa and the Swedish amateur Grzegorz Duszanowicz discovered a comet of magnitude 18.5, showing a tail, in the constellation Horologium. Follow-up observations of comet C/2023 V4 (Camarasa-Duszanowicz) showed a strongly condensed, 8" coma of total magnitude 18.5 and a 0.3' long curved tail in p.a. 340°. The comet will pass perihelion at the solar distance of 1.12 AU on May 30, 2024, but will then unfortunately be on the opposite side of the sun relative to Earth and therefore difficult to observe. The comet is expected to peak at magnitude 14.0-14.5 in June 2024 (CBET 5315). It should be brighter than 16 mag between March and August 2024. During this period it will move through the constellations Cetus, Aries, Perseus, Auriga, Lynx, Ursa Major and Canes Venatici. For Central European locations it is positioned very low above the western to northwestern evening horizon until mid-June. It then begins to rise, reaching a maximum altitude of 30° at the end of July.
The comet actually reached magnitude 10.7 at the start of June 2024, based on 101 observations by 26 observers, most of which were achieved post-perihelion. The brightness development can be well represented with the parameters
m0 = 8.5 mag / n = 5.5.
The coma diameter increased from 1.5' (125,000 km) at the beginning of June 2024 to 2.8' (210,000 km) in mid-July. Until mid-September it had decreased to 0.3' (35,000 km). The degree of condensation was constant at DC 3-4. Post-perihelion a tail of up to 6' (1 mio. km) length could be detected via CCD.
Total Brightness and Coma Diameter
--------------------
On Jan. 16, 2024 the LEMMON project discovered an asteroidal object of magnitude 20 in the constellation Eridanus, which turned out to be a comet, according to follow-up observations. Comet C/2024 B1 (LEMMON) showed a highly condensed 7" coma of total magnitude 20.5m. It will pass perihelion on Oct. 7, 2024 in the solar distance of 1.63 AU, expected to reach magnitude 16.0 (CBET 5344). During the weeks around perihelion it will move through the constellations Ursa Major, Canes Venatici, Bootes and Corona Borealis. At mid-European locations it can be seen at altitudes of less than 25° above the northwestern evening horizon and the northeastern morning horizon.
Just a dozen observations can be used for a rough analysis. They hint towards a brightness development according to the brightness parameters
m0 = 9.0 mag / n = 6,
indicating a maximum brightness of 13.5 mag at the opening of November 2024. The coma reached a maximum diameter of 1.5'. At the start of 2025 the comet faded below 16 mag.
--------------------
On Mar. 3, 2024, Kacper Wierzchos discovered a comet with the 1.5m reflector on Mt. Lemmon. The comet, positioned in the constellation Draco, had a highly condensed, 4" coma of total magnitude 20.0-20.5 and a 6" tail in p.a. 320°. At a distance of 8 AU at discovery comet C/2024 E1 (Wierzchos) will not pass perihelion at a solar distance of 0.56 AU until Jan. 21, 2026, then predicted to peak around magnitude 7 (CBET 5364). However, at this time the comet will be on the opposite side of the Sun relative to Earth, thus being positioned close to the Sun, making observations very difficult. It should be brighter than 16 mag between June 2025 and July 2026. During this period it will move through the constellations Draco, Hercules, Corona Borealis, Hercules, Ophiuchus, Serpens, Sagittarius (perihelion), Microscopium, Grus, Phoenix, Sculptor, Cetus, Eridanus, Taurus and Gemini. From Central European locations it can be seen in the evening sky until the end of November 2025 (then only 11 mag) and then again between the end of February (about 8 mag) and mid-May 2026 (about 13 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.
--------------------
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 77 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 11,000 km! The coma was extremely condensed (DC 8-9). A tail was not observed. At the beginning of 2025 faded below 16.0 mag.
Total Brightness and Coma Diameter
--------------------
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.
--------------------
On Dec. 25/26 Martin Masek discovered a 14-15 mag comet in the constellation Indus in images taken with a 300mm telephoto lens (which is part of the Pierre Auger Observatory) in the course of his self-initiated search program. Comet C/2024 Y1 (Masek) showed a significantly condensed inner coma of approximately 15" and an outer coma of diameter 1.4', whose total magnitude he determined to be 15.0 mag. In addition the comet showed a 1.6' long, semicircular tail at p.a.=120...300°. The comet passed perihelion at the solar distance of 0.83 AU on Nov. 26, 2024, when it should have been of magnitude 15.0 mag (CBET 5487). Because it will approach Earth post-perihelion its brightness should remain fairly constant for several weeks. The comet was positioned in the far-southern sky during the most interesting weeks.
Only a dozen CCD observations can be used for a rough analysis. These indicate that the comet peaked at 14.5 mag at the end of December 2024, with the brightness decreasing to 16.0 mag by the end of January 2025. The brightness parameters can be roughly determined as
m0 ≈ 14.5 mag / n ≈ 3.
The apparent coma diameter measured 1.5-2.0'.
--------------------
On Oct. 11, 2024 comet 37P/Forbes (P=6.44a) will pass perihelion for another time, this time at the solar distance of 1.62 AU, expected to reach magnitude 13.5. Between June and December 2024 it should be brighter than 16 mag. During this period it will move through the constellations Corvus, Hydra, Libra, Scorpius, Sagittarius into Capricornus. Thus it will be uncomfortably placed in the evening sky for mid-European locations, never attaining an altitude of more than 10°.
Just 23 CCD observations from 8 observers can be used for a rough analysis. These indicate a time-dependent development of the activity and can be best described by the parameters
m0 = 12.5 mag / nt = 0.02,
indicating that the comet peaked at 13.0 mag at the end of December 2024. The coma diameter measured 0.7' (60,000 km). The comet will now be unobservable until July 2025.
--------------------
Comet 49P/Arend-Rigaux (P=6.74a) can be observed in the evening sky with large instruments until the end of April 2025. It moves from the constellation Cetus into Taurus. The comet passes perihelion at the solar distance of 1.43 AU on Apr. 10, 2025.
Based on 17 CCD observations the brightness parameters can be roughly determined as--------------------
Comet 130P/McNaught-Hughes (P=6.22a) passed perihelion at the solar distance of 1.82 AU on Apr. 14, 2024. During the second half of the year it moves along the border of the constellations Cetus/Pisces.
Regarding its relative faintness this comet was observed surprisingly intensively. After all, 94 CCD observations from 16 observers can be used for the analysis. However, the observations exhibit a significant scatter, so that the brightness parameters can only be roughly determined as
m0 = 11.5 mag / n = 3.
Thus the comet peaked at 14.9 mag in September 2024. Until December it had faded to 16.0 mag. The comet showed a moderately condensed (DC 4) coma with a constant diameter of 0.9' (70,000 km). Between July and December 2024 a tail of up to 9' (2 mio. km) length could be detected, which was constantly oriented towards West.
Total Brightness and Coma Diameter
--------------------
Comet 146P/Shoemaker-LINEAR (P=8.08a), which passed perihelion on Aug. 5, 2024 in the solar distance of 1.42 AU, became 1.5 mag brighter than predicted. For a rouqh analysis only 21 CCD observations from 6 observers can be used. These hint towards a brightness development according to the rough parameters
m0 = 7.5 mag / n = 18,
yielding a maximum brightness of 14.8 mag in mid-August 2024. The diameter of the diffuse (DC 3) coma peaked at 0.8' (45,000 km). No tail was reported.
Total Brightness and Coma Diameter
--------------------
Comet 154P/Brewington (P=10.51a) passed perihelion in the solar distance of 1.55 AU on June 13, 2024. Until end of year it will move from Aries into the northwestern part of Leo, thereby continually fading.
Although the comet was well observable after perihelion not even 20 observations could be used for a rough analysis, which show a time-dependent brightness development (applying |t-T| instead of log r) according to the rough parameters
m0 = 10.5 mag / nt = 0.04
The comet peaked at 12.0 mag around the time of perihelion. At the end of September the comet had already faded to 16.5 mag. Between mid-June and early October the diameter of the diffuse (DC 3) coma shrank from 1.8' (175,000 km) to 0.8' (80,000 km). A tail was not reported.
Total Brightness and Coma Diameter
--------------------
Comet 333P/LINEAR (P=8.67a) will pass perihelion in the solar distance of 1.11 AU on Nov. 29, 2024. It is predicted to reach magnitude 10.5, because it will approach Earth on Dec. 9 to within 0.54 AU. The comet should become observable in mid-October 2024 in the morning sky as an object of magnitude 14. Until the end of year it will move through the constellations Sextans, Leo, Ursa Major, Canes Venatici (perihelion), Ursa Major, Draco (perihelion) into Cygnus. Earth will cross the orbital plane on Jan. 16, 2025.
The comet showed a rapid increase and decrease in activity, as 81 observations by 33 observers indicate. The brightness development can be represented reasonably well with the parameters
m0 = 11.0 mag / n = 12.
The comet peaked at 11.1 mag at the time of perigee. At the beginning of November 2024 it was only of magnitude 14.0 and by the end of January 2025 it had already faded to 16.0 mag. The apparent coma diameter measured 1.5' at the beginning of November 2024, increasing to 3.0' by the time of perigee. By mid-January 2025 it had shrunk to less than 0.5'. The absolute coma diameter shrank throughout the apparition, from 90,000 km to 20,000 km. In parallel the degree of condensation decreased from DC 4 to DC 2. A tail up to 4' (300,000 km) length was observed throughout the apparition. It changed its orientation from West over North to Northeast.
Total Brightness and Coma Diameter
--------------------
Comet 487P/Siding Spring (P=8.67a), which passed perihelion on Oct. 20, 2024 at the solar distance of 1.81 AU, was followed by CCD observers. On the basis of only 39 observations from 14 observers the brightness development can only be roughly represented with the parameters
m0 = 11.5 mag / n = 6.
This results in a peak brightness of 15.0 mag in mid-November 2024, when it was closest to Earth at 0.88 AU. At the end of December it had faded below 16 mag. The moderately condensed (DC 4) coma constantly measured 0.4' (16,000 km). A tail with a maximum length of 2' (200,000 km) was directed towards WSW at the beginning and towards SSW at the end of the apparition.
Total Brightness and Coma Diameter
Andreas Kammerer