In mid-October of this year, Comet Tsuchinshan-ATLAS graced the evening sky with its magnificent appearance. Its incredible beauty amazed astronomy fans all around the world. The Subaru Telescope facility in Hawai`i hosted a special live broadcast by temporarily installing a camera aimed at the western sky. Let’s revisit the highlights of this event.
Figure 1: Comet Tsuchinshan-ATLAS captured by the camera used for the special live streaming, seen in Maunakea’s evening sky on October 13, 2024 (Hawaii Time). (Credit: NAOJ & The Asahi Shimbun)
The comet was forecasted to appear in the eastern sky in late September, as seen from Maunakea, where the Subaru Telescope is located. The eastern sky is monitored by the "Subaru-Asahi Star Camera," a joint project between the National Astronomical Observatory of Japan (NAOJ) and The Asahi Shimbun. True to predictions, the comet was first captured by the keen viewers at dawn on September 22 (Hawaii-Aleutian Standard Time) amidst the predawn glow.
Although the comet initially appeared faint, nearly blending in with the dawn light, it grew more prominent daily. Around its perihelion (closest to the Sun) passage, the comet showed viewers a straight, majestic tail spanning half the camera’s field of view (Highlight videos 1-4).
Figure 2: The day-by-day evolution of Comet Tsuchinshan-ATLAS in the eastern sky from late September to early October. Provided by the viewer "Watashi-meme." (Credit: NAOJ & The Asahi Shimbun)
After passing close to the Sun, the comet was forecasted to reappear in the western sky on October 11. In preparation, NAOJ and The Asahi Shimbun installed a temporary camera aimed westward to deliver a live view of the celestial spectacle. On October 11, shortly after sunset, the comet was first glimpsed amidst the still-bright twilight sky by viewers of our live stream (Highlight video 5). The following evening, October 12, the comet gained altitude and appeared magnificently against the post-sunset sky, leaving many views awe-struck.
From October 13 onwards, as the comet rose higher in the sky, its visibility improved significantly (Highlight videos 6-10). Viewers enjoyed the beauty of the comet along with the stunning sunsets from Maunakea’s summit.
In Hawai`i, October 17 marked the full moon, and on that night, even the brilliant Great Comet appeared somewhat subdued due to the moonlight. However, on the following day, October 18, as the full moon began to wane and the comet became visible before the moonrise, it regained its original splendor (Highlight video 11).
Figure 3: The day-by-day changes in the appearance of Comet Tsuchinshan-ATLAS in the western sky in mid-October. Provided by the viewer "Watashi-meme." (Credit: NAOJ & The Asahi Shimbun)
On October 18 (Japan Time: October 19), the comet’s real-time live stream was featured during Japan’s nationwide simultaneous lecture event commemorating the 100th anniversary of planetariums and the 25th anniversary of the Subaru Telescope (Related Links). This event connected planetariums across Japan with the Subaru Telescope, and our live view of the comet over Maunakea added a special highlight to the occasion.
Our special live streaming ended up being a ten-day-long event in October, sharing the majesty of the comet with a global audience. With over 120,000 total views, more than 70% of which came from outside Japan, the event became an international success.
Comets are messengers from the outermost reaches of the Solar System, elucidating the origins of the Earth and life. We hope that children who were inspired by this comet’s beauty will one day pursue astronomy and visit Hawai`i for observations. Finally, we are deeply grateful for the opportunity to share this beautiful celestial phenomenon with the world from Maunakea, a site of immense cultural, historical, and natural significance in Hawai`i.
Highlight Videos
1. Comet Tsuchinshan-ATLAS Passed Periherion, Maunakea, Hawai`i, Morning 2024-09-28 (HST)
2. Comet Tsuchinshan-ATLAS, Near the Final View at Eastern Sky, Maunakea, Hawai`i, Morning 2024-10-02 (HST)
3. Comet Tsuchinshan-ATLAS, Near the Final View at Eastern Sky, Maunakea, Hawai`i, Morning 2024-10-05 (HST)
4. Comet Tsuchinshan-ATLAS Still Remains in the Eastern Sky over Maunakea, Hawai`i, morning 2024-10-09 (HST)
5. Comet Tsuchinshan-ATLAS Moved to the Western Sky: The First View from Maunakea, Hawai`i, 2024-10-11 (HST)
6. Sunset Sky and Comet Tsuchinshan-ATLAS: A Live View from Subaru, Maunakea, Hawai`i, 2024-10-12 (HST)
7. Sunset Sky and Comet Tsuchinshan-ATLAS: A Live View from Subaru, Maunakea, Hawai`i, 2024-10-13 (HST)
8. Sunset Sky and Comet Tsuchinshan-ATLAS: A Live View from Subaru, Maunakea, Hawai`i, 2024-10-14 (HST)
9. Sunset Sky and Comet Tsuchinshan-ATLAS: A Live View from Subaru, Maunakea, Hawai`i, 2024-10-15 (HST)
10. Sunset Sky and Comet Tsuchinshan-ATLAS: A Live View from Subaru, Maunakea, Hawai`i, 2024-10-16 (HST)
11. Sunset Sky and Comet Tsuchinshan-ATLAS: A Live View from Subaru, Maunakea, Hawai`i, 2024-10-18 (HST)
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