Images of the Week 2025

23 April 2025: No, you are not seeing double in this panorama of telescopes that make up the SMARTS (Small and Moderate Aperture Research Telescope System) Consortium at the U.S. National Science Foundation Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF NOIRLab. Though they look similar from the outside, the SMARTS–GSU 0.9-meter Telescope (left) and the SMARTS–GSU 1.5-meter Telescope (right) have slightly different observing roles. The SMARTS–GSU 1.5-meter telescope hosts a special instrument called CHIRON. This spectrograph measures precise radial velocities to confirm the existence of stellar companions. The SMARTS–GSU 0.9-meter telescope, on the other hand, is fitted with the Tek2K instrument, a charge-coupled device (CCD) used for creating astronomical images. Both the SMARTS–GSU 0.9-meter and the SMARTS–GSU 1.5-meter are primarily used for the RECONS (REsearch Consortium On Nearby Stars) program, which measures the distances to nearby stars and detects unseen companions by using a variety of observational techniques. RECONS has been …

16 April 2025: Countless star trails appear as colorful brushstrokes spread across the night sky above NSF–DOE Vera C. Rubin Observatory, jointly funded by the U.S. National Science Foundation (NSF) and the U.S. Department of Energy (DOE) Office of Science. This mesmerizing image was created using long-exposure photography, a technique in which a photographer allows light to enter their camera lens for a period of several minutes to several hours. The camera captures the subject’s movements, and the resulting image shows the flow of time in a single shot. During its decade-long Legacy Survey of Space and Time (LSST) Rubin will use a technique known as difference imaging: equipped with the largest camera ever built, Rubin will image the southern sky every few nights. Scientists will stack the best images in each filter each year into ultra-long exposures and create template images of the southern sky. When this template is compared to individual …

9 April 2025: Pictured here under a moonlit sky, high on the slopes of Maunakea, are two of the world’s most advanced astronomical observatories. In the foreground is the iconic dome of Gemini North, one half of the International Gemini Observatory, supported in part by the U.S. National Science Foundation and operated by NSF NOIRLab, and in the background is the Canada-France-Hawaii Telescope. In the upper right corner of the image is the Moon blazing with reflected sunlight. Astronomers have a complex relationship with the Moon. Studying it has offered insights into the early Solar System and the history of Earth. The Moon is a familiar object that drives interest in astronomy as it is usually the first object observed by young people and it’s easy for anyone to observe. As a result, it is frequently used in public engagement programs. However, it’s a hindrance to many types of observations because of the …

2 April 2025: This Image of the Week captures the mesmerizing Geminids meteor shower above the NSF McMath Pierce Solar Telescope at U.S. National Science Foundation Kitt Peak National Observatory (KPNO), a Program of NSF NOIRLab, as the Milky Way rises high into the sky. The annual Geminids shower happens when Earth passes through the debris trail of asteroid 3200 Phaethon in December and this debris collides with our atmosphere to then explode into fiery streaks of light. The Geminids is unusual among meteor showers because it is one of two major showers not caused by a comet. Two telescopes at KPNO are used to study asteroids: the UArizona 0.9-meter and 1.8-meter Spacewatch telescopes. The University of Arizona’s Spacewatch Program was founded to explore the various populations of small objects in the Solar System and study the statistics of asteroids and comets to investigate the dynamical evolution of the Solar System. The decommissioned …

26 March 2025: In an alignment of celestial bodies, Mars was captured here rising out of a lunar occultation on 13 January 2025 using the new Visitor Center 0.6-meter Shreve Telescope at the U.S. National Science Foundation Kitt Peak National Observatory (KPNO), a Program of NSF NOIRLab, near Tucson, Arizona. An occultation is when an object becomes hidden from an observer’s view by another object passing between them. The passing object must be larger than the hidden object. Otherwise the event is a transit, such as the transit of Mercury in front of the Sun in 2019, as photographed from NSF Cerro Tololo International Observatory (CTIO), another Program of NSF NOIRLab. Three days after this photo was taken, Mars was in opposition to the Sun from our point of view on Earth, so coming out of occultation the red planet was almost fully sunlit and appeared brighter and bigger than usual. Two evening …

19 March 2025: During the night of 13 to 14 March 2025, the sky was embellished by this total lunar eclipse. Lunar eclipses occur when Earth is positioned between the Sun and the Moon. In this position, the Moon enters Earth’s shadow as Earth prevents the Sun’s light from reaching the Moon directly. In this alignment, the Moon isn’t completely dark — instead, it is drenched in a red glow, as some sunlight passes through Earth’s atmosphere to reach the Moon. Rayleigh scattering of the sunlight in Earth’s atmosphere causes this ‘bloody’ color by scattering the light with shorter, bluer wavelengths more from their path than light of longer, redder wavelengths. NOIRLab's photo ambassador, Petr Horálek, captured the phenomenon at NSF Cerro Tololo Inter-American Observatory (CTIO) in Chile. This composite image — which was selected as Astronomy Picture of the Day 15 March 2025 — records the progression of the eclipse. Another photographer …

12 March 2025: Have you ever wished upon a shooting star? Shooting stars are not actually stars at all, but are seen when small rocks from space, called meteoroids, smash through the Earth’s atmosphere. The rocks as they pass through the atmosphere cause a streak of light and become a meteor. This photographer was lucky enough to capture a meteor here in this image of Gemini North, one half of the International Gemini Observatory, supported in part by the U.S. National Science Foundation and operated by NSF NOIRLab. Easily visible meteors are often part of large showers that occur when Earth passes through the trail of debris left by a comet and appear in rapid succession in the night sky. These meteor showers happen at specific times of the year and last for predictable periods of time. Lone meteors, like the green streak in the upper center of this image, are random events …

5 March 2025: Arizona’s night skies are perfect for stargazing, thanks to infrequent clouds, high elevation, and strict light pollution controls. This breathtaking shot shows the Milky Way above U.S. National Science Foundation Kitt Peak National Observatory (KPNO), a Program of NSF NOIRLab. KPNO is the largest assembly of optical instruments in the northern hemisphere and is a leading site for astronomical research. The Burrell Schmidt telescope on the left was relocated to KPNO from Case Western Reserve University to escape the increasing light pollution in Cleveland, Ohio. In the middle is the 0.9-meter SARA Kitt Peak Telescope. It was originally known as the No. 1 36-inch telescope of the predecessor of NOIRLab, National Optical Astronomy Observatories (NOAO), but today the telescope is operated by the Southeastern Association for Research in Astronomy, a consortium of universities throughout the southeast United States. This group combines their resources to support astronomical research by their faculty …

26 February 2025: The Milky Way shares the stage with a luminous bubble of green and orange airglow in this panoramic image of Gemini North, one half of the International Gemini Observatory, supported in part by the U.S. National Science Foundation (NSF) and operated by NSF NOIRLab. Gemini North (right) is accompanied here by the Canada-France-Hawai‘i Telescope (CFHT) (left). In this image, you could remove all of the stars, the brilliant stripe of the Milky Way, and the nearby city lights of Hilo, Hawai‘i (far left), and you would still be left with a picture that isn’t completely dark. This is thanks to the persistent light of airglow. Airglow is primarily caused by sunlight interacting with atoms and molecules in Earth’s upper atmosphere, which allows them to gain excess energy. This excess energy is then released as a particle of light called a photon. The frequencies of the photons determine the captivating colors …

19 February 2025: This galaxy, NGC 3109, is a somewhat nondescript — but fascinating — member of our Local Group of galaxies. Located around four million light-years from Earth in the constellation Hydra, it’s about 40,000 light-years across. Despite its beautiful blue hues, this irregular dwarf galaxy appears featureless with no central bulge or picturesque arms. However, spectroscopic analysis has shown that NGC 3109 is one of the most metal-poor galaxies in the Local Group. For most of us, metals are conductive, malleable elements like aluminum or copper, but to astronomers metals are all elements other than hydrogen and helium — such as carbon, nitrogen and oxygen. Stars consume hydrogen and helium to produce heavier elements. These metals are released into the interstellar medium when a star dies and are found in successive generations of stars. Metal-poor galaxies like NGC 3109 have a similar composition to the stars — and therefore the galaxies …

12 February 2025: Comet C/2024 G3 (ATLAS) is captured here in all its beauty by Cesar Briceño, Director of the Southern Astrophysical Research Telescope (SOAR), a part of the U.S. National Science Foundation (NSF) Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF NOIRLab. Comets form from a nucleus of dust, water, and gas in the farthest-known regions of our Solar System. This close-up of the Comet C/2024 G3 (ATLAS) cleanly shows the vaporized material of the nucleus creating the iconic cometary shape. In the lower left corner, the diffuse coma shines bright white as it obscures the nucleus. Emanating from the nucleus are the twin tails. The upper stream is the dust tail made of the heavier dust particles, illuminated by reflected sunlight. The lower stream is composed of gases, glowing as a result of ionization of the gas atoms. This tail is affected by the Sun’s magnetic field, and so is …

5 February 2025: Gemini North, one half of the International Gemini Observatory, supported in part by the U.S. National Science Foundation and operated by NSF NOIRLab, sits atop Maunakea under a hypnotic sky filled with circular star trails in this Image of the Week. Stars appear to move across the sky during the night as a result of Earth’s rotation. This effect is captured beautifully here using long-exposure photography, a photographic technique where stationary objects appear defined while moving objects appear blurred. In this image, these dizzying arcs of light trace the apparent motion of stars in the sky. Stars that are far away from the celestial poles appear to move more over time and thus display longer star trails compared to stars near the celestial poles. At the center of these arcs is the star Polaris, which appears to stay fixed in one spot because it’s located almost directly above Earth’s North …

29 January 2025: Comet C/2024 G3 (ATLAS) gleams against the January sky above three NOIRLab-supported telescopes in this Image of the Week. This is the first time that humans have observed this comet, which was last visible from Earth about 600,000 years ago. At perihelion, this comet reached an apparent magnitude of -3.8. This is about the same brightness as Venus, on the right side of the image, and potentially makes it the brightest comet of 2025. The straight lines across the sky are satellites, more prominently visible in this close-up. This image was taken atop Cerro Pachón, in the foothills of the Chilean Andes, next to the Southern Astrophysical Research Telescope (SOAR), a part of the U.S. National Science Foundation (NSF) Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF NOIRLab. In the distance are two other observatories supported by NSF NOIRLab (left to right): Gemini South, one half of the International …

22 January 2025: This Image of the Week showcases the stunning Milky Way gracefully arcing over the NSF Víctor M. Blanco 4-meter Telescope at the U.S. National Science Foundation Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF NOIRLab in Chile. CTIO is located at an altitude of 2200 meters (7200 feet) in the remote mountains of Chile. This location, high in the sky and far from city light pollution, allows telescopes like the Blanco Telescope to study the sky in breathtaking clarity. This image encapsulates the beauty of the cosmos and the sophisticated efforts undertaken by astronomers to unravel its mysteries. One such effort in which this telescope has played a major role is the Dark Energy Survey (DES). The survey examined the origin of the accelerating Universe to uncover the nature of dark energy by measuring the 14-billion-year history of cosmic expansion. Over a six-year period, this telescope, armed with the …

15 January 2025: NSF–DOE Vera C. Rubin Observatory, jointly funded by the U.S. National Science Foundation (NSF) and the U.S. Department of Energy (DOE) Office of Science, is seen here on the low ridge of Cerro Pachón in Chile with snow-dusted mountains in the background. With an altitude of more than 2600 meters (8600 feet) at Rubin Observatory, Cerro Pachón is an ideal location for astronomical research with its dry, stable air. The 8.4-meter Simonyi Survey Telescope at Rubin Observatory, equipped with the LSST Camera — the largest digital camera in the world — will survey the entire southern hemisphere every few nights for a decade to create an ultra-wide ultra-high-definition time-lapse record of our Universe. This unique ‘movie’ will bring the night sky to life, yielding a treasure trove of discoveries. Rubin is positioned near two other observatories in the foothills of the Chilean Andes: the Gemini South telescope, seen at upper-right, …

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.