Comet Tsuchinshan-Atlas photos captured by TAO

The University of Tokyo's Atacama Observatory (TAO) hit an exciting milestone on September 30, 2024, by capturing images of Comet Tsuchinshan-Atlas (C/2023 A3) from their summit facility. Perched at an incredible altitude of 5,640 meters on Cerro Chajnantor in Chile, the observatory had a fantastic vantage point, giving astronomers a clear view of the comet—even with some tricky weather conditions. It's always thrilling to see how the right equipment in the right spot can bring us closer to these cosmic visitors!

Pictured above: Still photograph of Comet C/2024 A3 (06:09, 30, Sept. 2024) The photograph would like to have been taken early in the dark hours, however clouds in the eastern sky meant that we had to take photographs in twilight. Even so, the comet was clearly visible to the naked eye in the twilight. Photo credit: "Photographed by TAO Project, The University of Tokyo/Akio Nakanishi"

Stunning images of Comet Tsuchinshan-Atlas captured at the TAO summit facility

Comet Tsuchinshan-Atlas, discovered by astronomers at the Tsuchinshan Observatory in China in January 2023 and later confirmed by the ATLAS telescope in South Africa, is a large comet with a nucleus estimated to be between 20 and 40 kilometers in diameter. Originating from the Oort Cloud, the comet's path around the sun is non-periodic, meaning it only approaches the sun once. As the comet neared the sun, its icy nucleus released gas and dust, creating the iconic glowing tail visible in the images.

Although predicting the brightness of comets is notoriously difficult, astronomers initially speculated that Tsuchinshan-Atlas might reach a magnitude as bright as minus 4 or 5 by the time it neared Earth. However, this prediction changed after a sudden brightening in early 2024, likely caused by partial disintegration of the comet's nucleus. More recent predictions, as of late September 2024, suggest a magnitude of around 2 or 3. At its closest approach to Earth around October 12, it could achieve a brightness near 1 or minus 1. During late September and early October, observers in the Northern Hemisphere could see the comet in the low eastern sky at dawn, with visibility shifting to the southwestern sky after sunset in mid to late October.

The TAO project, launched in 1998 by Professor Yuzuru Yoshii, has been under development for decades and is still constructing its flagship 6.5-meter telescope. This telescope, once completed, will provide astronomers with advanced capabilities to observe the cosmos from one of the best observation sites in the world. However, for this event, the images of Comet Tsuchinshan-Atlas were not captured using the under-construction TAO telescope. Instead, alternative instruments were used to photograph the comet during the pre-dawn hours on September 30, 2024.

Photographs of Comet Tsuchinshan-Atlas at the University of Tokyo Atacama Observatory

The first successful image was taken just after 6:00 AM, but clouds in the eastern sky delayed the initial shots until twilight. Despite these challenges, the comet was clearly visible to the naked eye, a rare sight in modern astronomy. The TAO team shared the images on their website, noting that these would be followed by further photographs taken in the coming days. Additionally, they produced a time-lapse video comprising 1,005 still images captured over nearly two hours on the morning of September 30. The video reveals the comet's tail emerging from behind the clouds, with its nucleus appearing as the twilight intensified.

Pictured above: Comet Tsuchinshan-Atlas, the TAO enclosure, the Milky Way, and the Large Magellanic Cloud. The tail of Comet can be seen extending vertically in the left center of the photo. The TAO enclosure is towering on the right edge of the photo. In the center, the light belt of Milky Way extends from high in the eastern sky to the southeastern horizon. The Large Magellanic Cloud can also be seen between the Milky Way and the enclosure. ( Time of the photo: 30 Sep 2024, 6:07 AM (CST), Camera: Canon EOS M2, Lens: SIGMA 10mm F2.8 EX DC Fisheye HSM, Exposure time: 13 sec, F-number: F2.8, Sensitivity: ISO3200, Color profile: sRGB). Photo credit: "Photographed by TAO Project, The University of Tokyo/Hidenori Takahashi"

Assistant Professor Hidenori Takahashi, who participated in the observation, reflected on the excitement of witnessing such a rare astronomical event firsthand. He explained that while astronomers often work with instruments that quantify data invisible to the human eye, they also find joy in visually experiencing the night sky’s wonders. He described the breathtaking moment when the comet’s faint light emerged from the eastern sky and how the starry view at the summit, combined with the comet's appearance, left a lasting impression on him. He also noted that, although the comet would soon become obscured by the sun’s position, it would be visible again after October 12, when it reappears in the western sky following its closest approach to Earth.

The TAO team captured not only the comet but also a spectacular view of the Milky Way and the Large Magellanic Cloud. The images show the comet's tail extending vertically while the TAO enclosure and the bright band of the Milky Way dominate the background. These striking images, taken with a Canon EOS M2 camera equipped with a Sigma 10mm fisheye lens, highlight the incredible observational conditions at the summit of Cerro Chajnantor.

This successful photographic documentation of Comet Tsuchinshan-Atlas marks a significant achievement for the University of Tokyo's Atacama Observatory, contributing to our understanding of the comet's behavior as it nears the sun. The images and video provide astronomers and the public alike with a rare glimpse of one of the most anticipated celestial events of 2024. The TAO team, alongside the global astronomical community, eagerly anticipates further observations of the comet in the coming weeks as it continues its journey through the inner solar system.