Home=Current Comets: 24P (2025/26)
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During the winter months 2025/26 comet 24P/Schaumasse (P=8.18a) should become an object that should be easily visible through a telescope and probably even in binoculars. It will pass perihelion at a solar distance of 1.18 AU on Jan. 8, 2026. On Jan. 4, 2026 it will come to within 0.59 AU to Earth. There are different approaches concerning the brightness parameters. While a high activity parameter of n = 12 is generally assumed, values between m0 = 7.5 mag and m0 = 9.5 mag are discussed for the absolute magnitude. Accordingly, the brightness should increase from 13 mag (11 mag) in mid-November 2025 to 10.5 mag (8.5 mag) in early January 2026, thereafter fading to 11.5 mag (9.5 mag) by mid-February. During the winter months of 2025/26 the comet can be observed in the morning sky. It will move from the constellation Cancer to the border of of the constellations Bootes/Virgo, where it will reach its maximum brightness of 10.5 mag (possibly 8.5 mag). The Earth will cross the comet's orbital plane on Dec. 10.
The comet shows high activity parameters both pre- and post-perihelion, with the activity increasing more rapidly pre-perihelion than decreasing post-perihelion. At the end of October 2025 the brightness was only 15.0 mag, while at the beginning of February 2026, the comet was still 10.0 mag bright. Based on 281 observations by 51 observers (until the start of Februar 2026), the brightness parameters are as follows:
pre-perihelion: m0 = 7.1 mag / n = 18The comet thus reached a maximum brightness of 9.1 mag around Jan. 10, 2026.
Total Brightness and Coma Diameter
While the coma measured only 1.5' (60,000 km) at the end of October 2025, it grew to a maximum of 10' (260,000 km) by mid-January 2026. Thereafter it slowly decreased, measuring apparently 7' (190,000 km) at the beginning of February. The coma was always rather diffuse, with a faint central condensation discernible. The degree of condensation remained constant at DC 3 so far. Tail reports, even via CCD, have been rather rare, reaching lengths of 7' (250,000 km) immediately after perihelion passage. The tail was constantly oriented towards West.Andreas Kammerer
