Image of the Week

20 November 2024: The Milky Way dominates the sky as it stretches over U.S. National Science Foundation Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF NOIRLab, which is located high in the mountains of Chile, at an altitude of 2200 meters (7200 feet). CTIO is a complex of astronomical telescopes and instruments that has long served as the principal platform for American astronomical investigation of the southern skies. In addition to the many telescopes it operates, CTIO provides space for others to access the southern sky — almost a dozen tenant observatories are hosted at the site. Pictured here are telescopes operated by Las Cumbres Observatory (LCO). LCO operates a network of telescopes spread out longitudinally across the northern and southern hemispheres. The strategic positioning of its telescopes means that LCO always has a telescope in darkness and it can coordinate its telescopes to quickly collect data that would be missed by …

13 November 2024: Gemini South, one half of the International Gemini Observatory which is supported in part by the U.S. National Science Foundation and operated by NSF NOIRLab, sits high atop Cerro Pachón in Chile, surrounded by gems of the southern night sky. One of these gems, the center of our Milky Way, is also the center of this image. The heart of our galaxy, densely packed with stars, is home to a supermassive black hole, known as Sagittarius A*, surrounded by the colossal clouds of cosmic dust of the Great Rift. While difficult to see in this image, these dark clouds house many interesting and beautiful deep-sky objects, like Ptolemy’s Cluster (Messier 7) and the Cat’s Paw Nebula (NGC 6334). Below the densest part of the Milky Way in this image is the constellation Scorpius (the Scorpion), which is best seen from southern latitudes. Its three-pronged ‘head’ and ‘claws’ stretch out from …

6 November 2024: The starry band of the Milky Way hangs overhead in this panorama taken from Maunakea, the home 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. Down on the mountain at the center of the image, a snaking band of light marks the location of an access road. In the distance, the large cities on the Island of Hawai‘i light up spots under the clouds while the active volcano Mauna Loa rises above them. Just like Mauna Loa, Maunakea is a shield volcano — though thankfully a dormant one. However, the volcanic past of Maunakea continues to be an asset to astronomers. The mountain’s smoothly sloping sides and high elevation are two of the factors that contribute to the exceptional observing conditions at the summit.

30 October 2024: The Milky Way is a disk-shaped spiral galaxy with many arms, each holding countless stars and celestial objects. Often, the most common view of the Milky Way is of the brightest and most concentrated region of the galaxy in the direction of the constellation Sagittarius. This photographer instead looked toward Orion — identifiable by the distinct three-star ‘belt’ — for this Image of the Week to capture the Orion-Cygnus Arm. The bright stars, clusters, and nebulae, such as the red giant Aldebaran (center) and the Orion Nebula (center right), that lie within the arm hold significance for cultures across the globe and are areas ripe for exploring many astrophysical processes. This section of the Milky Way is also where our Solar System is located. Pictured beneath this fascinating patch of sky is the Visitor Center Roll Off Roof Observatory at U.S. National Science Foundation Kitt Peak National Observatory (KPNO), a …

23 October 2024: Breathtaking views of astronomical events are a never-ending source of great excitement for the staff at Gemini North, one half of the International Gemini Observatory, supported in part by the U.S. National Science Foundation and operated by NSF NOIRLab. One such example is the lunar eclipse taking place in the distance on the right side of this image, captured in 2019. It is seemingly encased in the dark blue band above the horizon. Lunar eclipses occur when Earth moves between the Sun and the Moon. The Moon, which is only visible by the sunlight reflected off it, is darkened by the Earth’s shadow. An eclipse like this one can be viewed from anywhere on Earth where the Moon is visible, though the extent of the eclipse depends on how aligned the Moon is to Earth’s shadow and one’s viewing location. In 2022, for example, the two lunar eclipses, both total …

16 October 2024: A stunning view of the Milky Way above the U.S. National Science Foundation Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF NOIRLab, is captured in this Image of the Week. In addition to its largest and best-known telescopes, CTIO hosts around 40 telescopes from 11 tenant observatories and research projects. Shown here are many of the facilities operated by Las Cumbres Observatory (LCO), including the three Las Cumbres Observatory 1-meter Telescopes (left) and the ‘igloo’ for an echelle spectrograph (center). The Planetary Defense 1.3-meter Telescope is on the right. LCO is a global network of telescopes that are spaced out longitudinally around the globe, allowing for night-sky objects to be monitored around the clock. This ability to observe objects continuously is crucial in the field of time-domain astronomy, the study of how astronomical objects change with time. Time-domain astronomy is concerned with objects that change rapidly in brightness or …

9 October 2024: The Milky Way flows across the southern hemisphere’s night sky in this photograph of Gemini South, one half of the International Gemini Observatory. Supported in part by the U.S. National Science Foundation and operated by NSF NOIRLab, Gemini South resides on the summit of Cerro Pachón in Chile, a location well known for its dazzling dark skies. Here it’s operating its constellation of five laser guide stars, which is used by its advanced adaptive optics system to reduce the blurring of images that’s caused by Earth’s atmosphere. Speckled through the Milky Way are some iconic constellations: Centaurus (the centaur), Crux (the Southern Cross), and Canis Major (the Great Dog — which is distinguished by the brightest star in the sky, Sirius). The large red splotch in the Milky Way at the center of the image is the Carina Nebula, one of the largest diffuse nebulae in our skies. To the …

30 September 2024: 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 …

25 September 2024: In the southern constellation of Fornax lies NGC 922, a peculiar galaxy with a structure that has puzzled astronomers for years. Previously, researchers thought its distinctive features — the stellar plume and off-center galactic bar — resulted from a collision with a nearby dwarf galaxy some 330 million years ago. However, new observations have revealed an umbrella-like tidal tail, seen in this image taken with the DOE-built DECam on the U.S. National Science Foundation Víctor M. Blanco 4-meter Telescope at the Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF NOIRLab. These observations contradict the previous collision theory by showing that this newly detected tail doesn’t align with the trajectory of the dwarf galaxy. Moreover, the dwarf galaxy itself shows signs of ongoing star formation and has a well-defined structure, which is inconsistent with the aftermath of a direct collision. So, a new hypothesis has emerged: that these complex features …

18 September 2024: The star-filled Milky Way arches over Cerro Pachón in this Image of the Week, the sky alight with the spectacular green, orange, and purple airglow of Earth's upper atmosphere. On the right is Gemini South, one half of the International Gemini Observatory, supported in part by the U.S. National Science Foundation and operated by NSF NOIRLab, while on the left atop the structure is the DIMM3 Seeing Monitor. Both Gemini South and the DIMM3 Seeing Monitor are perched at an altitude of 8980 feet (2737 meters) in the mountains of Chile. This high location is known for its dry, stable air, and provides the excellent ‘seeing’ conditions needed to make high-quality observations. However, even in the best conditions, the turbulent atmosphere will still distort the data. That’s where the DIMM3 Seeing Monitor (and the two other DIMM monitors at Cerro Pachón) come in. A Differential Image Motion Monitor (DIMM) is …

11 September 2024: The disc of the Milky Way spreads across the eastern horizon of Hawaiʻi as it rises over the summit of Maunakea. The center of our galaxy silhouettes the Maunakea Observatories, including Gemini North (third from left), one half of the International Gemini Observatory, supported in part by the U.S. National Science Foundation and operated by NSF NOIRLab. At about 19 degrees north of the equator, Maunakea is in one of the most southerly locations in the United States. This makes it an excellent location to view large portions of the southern skies from the northern hemisphere, wonderfully captured in this stunning photograph. At the center of this image is the constellation Scorpius (the Scorpion), including the star Antares, its bright red ‘heart’. To its left is Ophiuchus (the serpent bearer). These two constellations are dotted with a variety of colorful nebulae. A closer look at these nebulae is in our …

4 September 2024: Above the U.S. National Science Foundation Cerro Tololo Inter-American Observatory (CTIO), the Milky Way elegantly stretches into the night sky from the horizon, as yellow, green, and red airglow seemingly permeate what would otherwise be a black sky in this Image of the Week. CTIO is a Program of NSF NOIRLab and is home to approximately 40 telescopes from 11 tenant observatories and research projects. Featured here is one such facility: the SARA Cerro Tololo Telescope, operated by the Southeastern Association for Research in Astronomy (SARA). SARA is a collaborative partnership of American universities that operate telescopes at multiple locations around the world, including the Canary Islands and Arizona (where the SARA Kitt Peak Telescope is hosted at NSF Kitt Peak National Observatory, another Program of NSF NOIRLab). The variety of locations provides essential observing opportunities to students and faculty from participating institutions, but the location of the SARA Cerro …

28 August 2024: This panorama image features 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 its neighboring telescopes on what appears to be on a flat landscape with low hills. But actually, these small peaks sit atop a much larger mountain. Maunakea is an inactive shield volcano and one of the tallest mountains on Earth. It rises 4205 meters (13,786 feet) above sea level, but extends about 6000 meters (19,700 feet) below sea level to meet the deep ocean floor. Its total height is nearly 10,211 meters (33,500 feet). The peaks seen in this image are actually cinder cones, steep conical hills that form around volcanic vents. They are typically composed of accumulations of pyroclastic rocks released during earlier eruptions. The deep red color of these cones comes from the iron-rich basaltic soil produced during those eruptions. …

21 August 2024: Behold NGC 6744, a spiral galaxy bearing similarities to our home galaxy, the Milky Way. This cosmic twin is captured here in stunning detail by the Dark Energy Camera (DECam) on the 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. Located around 30 million light-years away in the constellation Pavo, NGC 6744 exhibits a luminous core and spiral arms spanning 175,000 light-years across, a larger but similar anatomy to our Milky Way. Moreover, to the lower right of NGC 6744, at the end of the spiral arm, is a faint blob. This is its companion galaxy known as NGC 6744A. The companionship between these galaxies is analogous to that between the Milky Way and its dwarf companion the Large Magellanic Cloud. Though it’s impossible to get an external view of our galaxy, these similarities offer …

14 August 2024: A bolt of lightning illuminates clouds hanging above Maunaloa in Hawai‘i, the volcano opposite Maunakea which is home 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. While the site of superb observing conditions of the night sky for 80% of the year, the summit of Maunakea is occasionally disturbed by thunderstorms like the one shown here above Maunaloa. A smaller second bolt of lightning can also be seen shrouded in the clouds on the left side of this photograph. Gemini North and other telescopes near the summit of Maunakea are only temporarily affected by these rare thunderstorms, and structures are generally built into the observatory buildings to mitigate lightning strikes on the telescopes themselves. You can view earlier Images of the Week featuring the lightning phenomena called a red sprite near Maunakea here and …

7 August 2024: The night sky above the WIYN 3.5-meter telescope at the U.S. National Science Foundation Kitt Peak National Observatory, a Program of NSF NOIRLab, is adorned with Jupiter (center right) and the Pleiades (upper right) in this Image of the Week. But the most impressive of all the adornments is Comet Pons-Brooks on the bottom right side of this image. This comet, with a nucleus about 30 kilometers (19 miles) in diameter, follows a 71-year orbit around the Sun. It was first recorded in 1812 by Jean-Louis Pons, and was then ‘discovered’ on its next passage near Earth by William Robert Brooks — hence the name Pons-Brooks. Comets orbit the Sun in elongated elliptical orbits. These relatively small, icy bodies are dark against the blackness of space so when they travel into the farthest parts of the Solar System they become invisible to us on Earth. Astronomers recover — or, in …

31 July 2024: NSF–DOE Vera C. Rubin Observatory atop Cerro Pachón in Chile is outlined against the full Moon rising above the horizon. A trick of perspective has enlarged the Moon beyond the size we’d naturally see it on Earth in this Image of the Week. Often regarded as an ‘enemy’ of non-lunar astronomers because of its brightness, the beauty of Earth’s natural satellite cannot be ignored. On the right side of the Moon in this image is the large and relatively young Tycho crater, with its distinctive ray system prominently spreading across the lunar surface. On the bottom and left side are large, dark maria, basaltic plains that formed during the early life of the Moon 1.2–4 billion years ago. The largest of the maria in this image is the Sea of Tranquility, the first site on the Moon visited by humans. This image was captured during the final phase of the …

24 July 2024: This ghostly, butterfly-shaped planetary nebula, captured with 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 known as Kohoutek 3-46. Kohoutek 3-46 derives its name from the prolific planetary nebula hunter who discovered it, Czech astronomer Luboš Kohoutek. Located in the constellation Cygnus, Kohoutek 3-46 is estimated to be around 20,000 years old and around 7200 light-years away. The term ‘planetary nebula’ is a misnomer, since these nebulae are unrelated to planets. The term originates from their planet-like round shape, more obviously seen in this earlier NOIRLab Image of the Week. Kohoutek 3-46 has expanded into an unusual bipolar shape, classified by its well-defined hourglass shape, prominent equatorial ring and marked waist. About 10–20% of planetary nebulae are bipolar. No matter the shape they take on, these glowing clouds of gas form after a star …

17 July 2024: Stars swirl around the south celestial pole in this timelapse image of the night sky captured at the Víctor M. Blanco 4-meter Telescope. The Blanco Telescope is located on the summit of Cerro Tololo in northern Chile, home to the U.S. National Science Foundation Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF NOIRLab. Photographers create timelapses like this by combining multiple long-exposure images of the night sky. As Earth rotates throughout the night, the stars appear to circle the north or south celestial poles. The southern hemisphere’s pole star, Sigma Octantis, is located in the middle of the ‘vortex’ in the image. It is fainter than the northern hemisphere’s more recognizable pole star, Polaris. To the upper left of the Blanco telescope, the illuminated pathways of two satellites intersect the star trails. The red squiggles in the foreground were created by someone walking with a red flashlight. Red lights …

10 July 2024: Majestic as it is mysterious, the Milky Way can easily illuminate the night sky in a dazzling flourish with just the right camera setting. Containing an estimated 100–400 billion stars, our barred spiral galaxy, the Milky Way, intertwines with interstellar dust to create a brilliantly complex bridge of light sprinkled across the sky. At the end of this bridge on the left lies Gemini North, the northern twin of the International Gemini Observatory, supported in part by the U.S. National Science Foundation and operated by NSF NOIRLab. Standing near the summit of Maunakea in Hawai‘i, the telescope’s location places it far away from light pollution and right among the stars for proper astronomical study. At the center, below the cloud deck forming at the bottom of the image, are the trapped city lights of Hilo. On the right, the faint glow of lava from the Kīlauea volcano lights up a …