ALPO Comet News December 2024

The Association of Lunar and Planetary Observers (ALPO) has released the December 2024 issue of its Comet News report. This publication, compiled by the ALPO Comets Section, provides a detailed analysis of current comet activity, including observations and updates from contributors worldwide. The full report is available on the ALPO Comets Section website and in the Comets Section Image Gallery. A shorter version, excluding images and magnitude estimates, is posted for accessibility.

In December, several comets are noteworthy. C/2023 A3 (Tsuchinshan-ATLAS) continues to fade, moving from 9th to 11th magnitude in the evening sky. Three additional comets are expected to reach brighter than 12th magnitude this month. Among these, 333P/LINEAR, a periodic comet with an 8.7-year orbit, is predicted to briefly surpass 10th magnitude before dimming. C/2022 E2 (ATLAS) will barely reach 12th magnitude before fading by month’s end. Both of these are observable primarily from the Northern Hemisphere.

In the Southern Hemisphere, C/2024 G3 (ATLAS) is predicted to brighten rapidly, reaching 5th magnitude. However, its position low on the horizon limits observation opportunities. By early January, this comet may become a negative magnitude object near perihelion, although it will likely be too close to the Sun for observation. As it moves away from the Sun, it may remain visible to the naked eye, though dimmer.

ALPO Comet News December 2024 section reports

The ALPO Comets Section reports receiving 140 magnitude estimates and 216 images of 44 comets in the past month. Among these comets are C/2024 T5 (ATLAS), C/2024 M1 (ATLAS), and 496P/Hill, reflecting the contributions of a dedicated network of observers. The Comets Section encourages the submission of textual descriptions, images, drawings, and spectra from both members and non-members. Observations can be emailed to the section coordinators, Carl Hergenrother and Michel Deconinck.

The report also discusses methods for photometric corrections applied to magnitude measurements. Observations are adjusted for variables such as aperture size, observer technique, and environmental factors, ensuring consistent data across various contributors. Visual observations are corrected to a standard aperture, while digital observations are adjusted based on individual observer characteristics. These corrections allow for accurate lightcurves and facilitate the study of comet behavior.

Acknowledgments are extended to contributors who provide observations and data. These include individuals submitting directly to ALPO, as well as those whose work appears in other databases such as the International Comet Quarterly, the Minor Planet Center, and the COBS Comet Observation Database. Special thanks are given to researchers and organizations that support the analysis, including Seiichi Yoshida for lightcurve and orbit visualization tools, and Syuichi Nakano and the Minor Planet Center for comet orbit data.

December 2024 report highlights

The December 2024 report highlights upcoming cometary activity and lunar phases. New Moon occurs on December 1 and 30, with a Full Moon on December 15. Perihelion events include several periodic comets, such as P/2024 T2 (Rankin) on December 8 and 242P/Spahr on December 23, among others. Observers are encouraged to monitor these events and submit findings to enrich the collective understanding of these celestial objects.

The ALPO Comets Section remains committed to fostering collaboration among amateur and professional astronomers. By compiling and analyzing observations, the section contributes to the broader astronomical community's knowledge of comets and their behavior. Those interested in learning more or submitting observations can visit the ALPO Comets Section website or contact the team directly.

This month’s report underscores the importance of shared observations and the collective effort to study these dynamic objects in the solar system. The ALPO extends its gratitude to all contributors for their continued support and dedication.