Images of the Week 2025

8 January 2025: A pivotal hub for astronomy sits in the Sonoran Desert, surrounded by the mountains of southern Arizona. Southwest of Tucson, the Quinlan Mountains majestically rise to an altitude of 2100 meters (7000 feet) in the Schuk Toak District of the Tohono O’odham Nation. Atop the central peak in this image sits the U.S. National Science Foundation Kitt Peak National Observatory (KPNO), a Program of NSF NOIRLab and the largest collection of optical and radio telescopes in the northern hemisphere. Kitt Peak’s ideal vantage point, combined with the dark, dry environment of the desert, allows astronomers to make discoveries in many areas of astronomy including exoplanets, galaxies, and dark energy. KPNO is just one of several observatories in the area, including the Mount Graham international Observatory and the Mount Lemmon Observatory, operated by the University of Arizona. In addition, Pima County, in which Tucson resides, is also a hub for space …

1 January 2025: On top of observing astronomical events in the northern skies, Gemini North — one half of the International Gemini Observatory, supported in part by the U.S. National Science Foundation and operated by NSF NOIRLab— is also set in an environment of gorgeous sunsets near the summit of Maunakea, Hawai‘i. Every so often, though, Gemini North is the site of something special. Upon closer inspection, a stream of shadow can be seen streaking across the right side of the image, outlined by parallel beams of light known as anticrepuscular rays. These rays are caused by clouds obscuring the dim, backscattered sunlight and appear to converge on a point directly opposite the Sun, known as the antisolar point. If these rays originated directly from the Sun, they would be called crepuscular rays. Anticrepuscular rays require the right environment to be created so they are difficult to glimpse.