Chasing Comet

🇬🇧  Traduire en français

Comets are celestial bodies composed mainly of ice, dust, and rock. Originating from the farthest regions of the Solar System — such as the Oort Cloud or the Kuiper Belt — they become spectacular when approaching the Sun. Solar heat causes their surface to sublimate, forming a luminous coma and sometimes a long tail that can stretch for millions of kilometers.

Throughout history, their sudden appearance in the sky was often seen as a bad omen. The Bayeux Tapestry, from the 11th century, famously depicts Halley’s Comet as a harbinger of the Battle of Hastings. These unpredictable objects have long fueled fear and legend.

Today, our perspective has changed. Thanks to advances in astronautics, we’ve been able to send probes to meet them. In 2014, the European mission Rosetta even succeeded in landing a module on the surface of comet 67P/Churyumov-Gerasimenko, revealing a complex and active world.

Resuming our observations

On June 27, 2025, we resumed our observations using our new 400 mm telescope. For this first light, we chose to observe comet C/2021 G2 (ATLAS), discovered in 2021 by the ATLAS system (Asteroid Terrestrial-impact Last Alert System). At the time of observation, the comet was visible in the constellation Libra. It had an estimated magnitude of around 15 and a coma approximately 0.3 arcminutes across.

The images were analyzed using the Tycho Tracker application to extract photometric measurements, which we submitted to the scientific community.

The image captured that evening reflects not only the capabilities of our new instrument but also the continuity of an observational effort spanning many years. We will soon revisit our archive of past observations, whose data have been shared with the scientific community.