English: Comet C/2023 A3 (Tsuchinshan–ATLAS) graces the dawn sky over the U.S. National Science Foundation Kitt Peak National Observatory, a Program of NSF NOIRLab, just outside Tucson, Arizona in this image. It was captured in the morning hours before sunrise on Saturday 28 September 2024 by Rob Sparks from NOIRLab. In the foreground is the McMath-Pierce Solar Telescope, which is in the final stages of being transformed into a must-see location for visitors to Arizona, currently named the Windows Center. Comets are dirty snowballs of gas, dust and ice, often from the far reaches of the Solar System. As a comet approaches the Sun, the solar radiation heats the icy body which then releases streams of dust and gas into space, forming the distinct tail.Comet Tsuchinshan–ATLAS was discovered in 2023 and is named after the two facilities that independently discovered it. From further observations of the comet, astronomers have estimated its orbital period to be 80,000 years and found that it’s particularly fast moving, traveling around 290,000 km per hour (180,000 miles per hour). Having reached its closest point to the Sun on 27 September, this comet will soon disappear from our view before it is expected to reappear in the evening sky in mid-October. On 12 October it will be at its closest point to Earth. For the following few days it could be easier to spot, before it fades from view as it flies back towards the outer Solar System.For many years, the McMath-Pierce Solar Telescope was the largest solar telescope in the world. Research with the facility was discontinued in 2017, but the approximately 8000-square-foot interior has been given a new life as a dynamic astronomy visualization and presentation center focused on astronomy funded by the NSF. Phase I includes a revamped front entrance, the first iteration of the Lobby area, a fully revamped Control Room, exhibits throughout the rest of the space, and a Science on a Sphere data visualization system. With the public opening scheduled for mid-2025, visitors can expect an experience built on NOIRLab’s foundational principle of Discovering Our Universe Together.Rob Sparks, the photographer, is a NOIRLab Audiovisual Ambassador. Another image of Comet Tsuchinshan–ATLAS, captured against the SOAR Telescope at the U.S. National Science Foundation Cerro Tololo Inter-American Observatory (CTIO) by photographer Carlos Corco, can be seen here. You can find more images of Comet Tsuchinshan–ATLAS in the NOIRLab Image Archive.