Image of the Week

12 July 2023: In Saguaro National Park East just outside of Tucson, Arizona, Connie Walker collects data for Globe at Night — a citizen science project aimed at tracking and reporting the impact of light pollution on the visibility of the night sky. She and Steve Pompea, scientist emeritus at NSF’s NOIRLab, created the project in 2006, with an easy to use web-application. Over 17 years Globe at Night has gathered extensive data on stellar visibility through the collective efforts of over 250,000 people around the world. In January 2023 a paper was published in the journal Science that analyzed Globe at Night’s user-submitted data and found that skyglow is increasing more rapidly than indicated by satellite measurements of the Earth’s nighttime surface brightness. Globe at Night is one of the many activities that NOIRLab supports to protect the night sky. In February 2022, NSF’s NOIRLab and the SKA Observatory (SKAO), an intergovernmental …

5 July 2023: The Víctor M. Blanco 4-meter Telescope has pristine access to wide open skies of the Chilean Andes from its perch at Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF’s NOIRLab. To the upper left of the telescope is the ‘evening star’, actually the planet Venus. Below on the left are the SMARTS 1.5-meter Telescope and SMARTS 0.9-meter Telescope (furthest back). Housed within the silver dome of the Blanco Telescope is the Dark Energy Camera (DECam), mounted at the prime (first) focus near the top of the white Serrurier truss. The blue U-shaped structure holding the truss is the large bearing that sweeps the telescope around to a designated position for observing. DECam saw first light on 12 September 2012 and in its more than 10 years of operation it has contributed greatly to the field of astronomy. It was designed specifically for the Dark Energy Survey, operated by the …

28 June 2023: This image shows Gemini North, one half of the International Gemini Observatory, operated by NSF’s NOIRLab, using a yellow-colored laser beam to adjust its adaptive optics system during commissioning in 2016. This laser emanates from the middle of the telescope and travels through Earth’s atmosphere. It excites traces of sodium 90 kilometers (50 miles) up in Earth’s upper atmosphere so that the system can measure the atmospheric turbulence. The telescope’s individual instruments then use a system of deformable mirrors to compensate for the effect of the turbulence and achieve sharp images of stars, planets, and galaxies at resolutions that rival space-based instruments. The dim lights inside the dome, turned on during telescope operation, cast the dome interior in a red glow. Through the dome opening, you can see stars streaking across the sky — the result of the long exposure used to capture this photo. You can see another view …

21 June 2023: The shadowy clouds of LDN 1622 are pictured in this observation from the Nicholas U. Mayall 4-meter Telescope at Kitt Peak National Observatory (KPNO), a Program of NSF’s NOIRLab. This image was captured in 2018 by the Mosaic-3 instrument, a wide-field camera used to capture large swaths of the night sky from Kitt Peak in Arizona. Mosaic-3 has since been retired to make way for the Dark Energy Spectroscopic Instrument (DESI), the most powerful multi-object survey spectrograph in the world. This swap highlights one of the benefits of ground-based astronomy: the ability to upgrade and replace instruments as new technologies become available. LDN 1622 is a dark nebula, so called because these dense interstellar clouds of gas and dust blot out light from background objects, appearing as ink-dark clouds against a backdrop of stars. This enigmatic cosmic cloud lies 1300 light-years from Earth in the nearby Orion complex, a star-forming …

14 June 2023: Below the southern skies, the telescopes of Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF’s NOIRLab, bask in the starlight of the brilliant Milky Way. Speckled with multi-colored stars, our home galaxy in this image stretches down into the city-lit horizon, just grazing past the Víctor M. Blanco 4-meter Telescope (left) and SMARTS 1.5-meter Telescope (right). The Small and Large Magellanic Clouds that accompany our home galaxy are seen to the left of the Blanco telescope. In between the telescopes blooms a deep shade of red that permeates through the tendrils of the Milky Way. This is the Gum Nebula, an emission nebula that blazes with the light of gas ionized by its host stars. From our perspective it holds a bountiful number of cosmic objects, from globular clusters, to the Vela Pulsar, and even to an 11,000-year-old supernova remnant. This photo was taken as part of the recent …

7 June 2023: The eighteen-story Nicholas U. Mayall 4-meter Telescope is located at Kitt Peak National Observatory (KPNO), a Program of NSF’s NOIRLab, and is seen here against the backdrop of two celestial landmarks of the northern hemisphere: The constellation Ursa Major (the Great Bear), with its seven bright stars that make the Big Dipper, on the right side of Mayall and the North Star Polaris on the left. The stars of the Big Dipper asterism are notable even on their own. The second star in the Big Dipper’s handle is Mizar and together with its fainter companion star Alcor they are known as the Horse and Rider. Their pairing is a naked-eye double since they appear to observers to be right next to each other. Because of their close proximity, trying to resolve the pair with only the naked eye has been a traditional sight test in many countries. The stars Merak …

31 May 2023: A rainbow cloud creates a stunning curtain of colors just after sunrise in this image taken from Cerro Pachón in Chile, home of one half of the International Gemini Observatory, the SOAR Telescope, and Vera C. Rubin Observatory, all operated by NSF’s NOIRLab. The appearance of pastel pigmentation sweeping across the sky is possibly due to the phenomenon known as cloud iridescence. Similar to the swirling colors on the surface of a bubble or oil spill, this optical effect occurs when sunlight passes through a particularly thin cloud that is composed of water droplets or ice crystals of uniform size. As the Sun’s rays encounter individual crystals, the light is both diffracted and scattered, revealing a gradient of the component wavelengths, or colors, that make up the Sun’s light. Because of the smooth, wavy shape of the clouds in this image, they closely resemble a different class of iridescent clouds …

24 May 2023: Star trails blur and lasers streak across the sky in this long-exposure view from Pu‘u Poli‘ahu, the mountain peak adjacent to the Gemini North telescope of the International Gemini Observatory, operated by NSF’s NOIRLab. Gemini North can be seen slightly to the right of the center of this image, shooting its laser into the sky. A handful of other telescopes that are part of the Maunakea Observatories in Hawai‘i surround Gemini North. Despite resembling searchlights or a battle from a sci-fi film, the lasers in this image play a vital role in correcting the vision of Gemini and the other cutting-edge telescopes. They are part of these telescopes’ adaptive optics systems, and help astronomers measure the distortions in their data caused by atmospheric turbulence. By continuously feeding these measurements into computer-controlled deformable mirrors, astronomers can compensate for almost all of the blurring caused by Earth’s atmosphere. This provides Gemini North …

17 May 2023: NGC 1808 is a barred spiral galaxy located in the southern constellation Columba (the dove). This image was captured using the Dark Energy Camera (DECam), which is mounted on the Víctor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF’s NOIRLab, in Chile. The core of NGC 1808 is thought to house a supermassive black hole, characterized by its accretion of material and higher-than-normal brightness. The smoldering center is closely surrounded by a faint blue ring populated with star clusters and supernova remnants. This region is defined by its starburst activity, producing an exceptional number of hot, bright, young stars. The abundance of rapid star formation is thought to be the result of past tidal interactions with the nearby galaxy NGC 1792. Laced throughout this middle region of NGC 1808 are dark dust lanes resulting from large outflows of hydrogen gas from the galactic nucleus. …

10 May 2023: The dynamic coloring of the night sky at Kitt Peak National Observatory (KPNO), a Program of NSF’s NOIRLab, makes for a beautiful backdrop behind the UArizona Bok 2.3-meter Telescope. Distant city lights, cars, airglow, and the arc of the Milky Way all add to the variety of colors. Zodiacal light emanating from the horizon intersects with the Milky Way on the right hand side of the image. One orange star at the center of this image stands out amongst the rest. This is the red supergiant Betelgeuse, a star that marks a ‘shoulder’ of the hunter constellation, Orion. Being a relatively old star, Betelgeuse glows a cool red compared to its hot, bright blue neighbors. Despite this, it is usually the 10th brightest star in the night sky. More compellingly, Betelgeuse is massive — so massive that its diameter is more than 750 times that as the Sun. This makes …

3 May 2023: Looking south across 100 kilometers (62 miles) of the Andean mountains in Chile, several telescopes dot the peaks on the horizon. On top of Cerro Pachón (center background), from left to right, are the Southern Astrophysical Research (SOAR) Telescope, the Gemini South telescope (one half of the International Gemini Observatory), and Vera C. Rubin Observatory. About 10 kilometers (6.2 miles) west is the mountain Cerro Tololo where the Víctor M. Blanco 4-meter Telescope sits (far right in the image). Both peaks have telescopes that are part of Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF’s NOIRLab. This image was captured from the site of La Silla Observatory, operated by the European Southern Observatory (ESO). The North Chile is home to a plethora of observatories all making the most of the dry desert climate, cloudless skies, and low light pollution. You can find a the complementary view of the La …

26 April 2023: Above the peaks of Cerro Pachón lies a bridge made of stars, intangible yet visible to the naked eye. This beautiful arch, composed of the Milky Way with its network of nebulae and interstellar clouds, seemingly connects the Rubin Auxiliary Telescope (AuxTel) (left) with the upcoming Vera C. Rubin Observatory (right), a Program of NSF’s NOIRLab. Some spectacles of the Universe dot around the Milky Way, from the Magellanic Clouds (center bottom) to the crimson emission nebulae (upper left and bottom right) to the green and red airglow on the horizon. Although it is possible to catch a glimpse of these treasures elsewhere on Earth, only in remote locations such as the highly elevated Andes can one truly bask in all their splendor. Rubin Observatory is a joint initiative of the National Science Foundation (NSF) and the US Department of Energy (DOE). Once completed, Rubin will be operated jointly by …

19 April 2023: Observing the night sky has never been so delightful as with this image of LBN 867, the Raspberry Nebula. Captured here by the Nicholas U. Mayall 4-meter Telescope using the Mosaic-3 detector at Kitt Peak National Observatory (KPNO), a Program of NSF’s NOIRLab, this nebula is located in the constellation Orion. LBN 867’s overall structure, though, is more like an onion than a raspberry: it hosts three different celestial objects in one! The characteristic red bloom of LBN 867 is an emission nebula. It glows as a result of the ionization of hydrogen gas by the light from the star HD 34989. From the center of the image, this main sequence star shines prominently, though it is about as bright as the planet Uranus as seen from Earth. The last object is hidden in plain sight. Notice the subtle bluish glow around HD 34989? This is the reflection nebula vdB …

12 April 2023: The silver dome of the Gemini North telescope, one half of the International Gemini Observatory, operated by NSF’s NOIRLab, catches the setting Sun, caught between the red-hued earth of the Maunakea volcano and an inky-blue sky. The scale of astronomical infrastructure can be difficult to grasp from images, particularly when telescopes are located in vast landscapes under wide skies. However, if you look closely the staircases winding up the side of Gemini North are visible — revealing the true size of this telescope. The dome of Gemini North — and that of its twin, Gemini South in Chile — is around 46 meters (150 feet) across, meaning that the two telescopes side-by-side would almost fit in an entire soccer field! This photo was taken as part of the recent NOIRLab 2022 Photo Expedition to all the NOIRLab sites.

5 April 2023: The McMath-Pierce Solar Telescope, located at Kitt Peak National Observatory (KPNO), a Program of NSF’s NOIRLab, is captured here beneath the full moon just after sunset. This is the perfect time of day to witness a phenomenon known as the anti-twilight arch, nicknamed the Belt of Venus. The belt forms directly opposite the rising or setting Sun — in this image, the Sun is setting in the west behind the camera. Rays of light from the Sun hit the eastern atmosphere at the antisolar point, the point directly opposite the sun from an observer’s perspective. The light is then backscattered off of the atmosphere and reflected back to the observer at a longer wavelength, changing the typically blue-appearing light into pink. The band of dark blue sky below the anti-twilight arch is actually the Earth’s shadow! You can find a diagram representation of this phenomenon here. This photo was taken …

28 March 2023: From the high altitude of Cerro Tololo Inter-American Observatory (CTIO) in Chile, two astrophotographers captured the elusive sunset phenomenon known as the green flash. This stunning trick of light occurs at sunset and sunrise when light from the Sun travels through the thickest part of Earth’s atmosphere. Acting like a prism, Earth's atmosphere bends, or refracts, the light and separates it into its component wavelengths. Blue and violet light are scattered by the atmosphere, while red, orange and yellow are refracted below the solar disk below the horizon, leaving the green light the most visible during the few seconds that the Sun disappears below the horizon. Here, though, is another uncommon phenomenon. Distinct thermal layers above the Pacific Ocean led to a Fata Morgana mirage displaying several green flashes. Two photographers from the recent NOIRLab 2022 Photo Expedition jointly worked the controls of the camera to quickly capture the elusive …

22 March 2023: The almost sheer cliffs of Cerro Pachón are surmounted by a trio of telescopes under an azure sky in this drone image. The three telescopes operated by NSF’s NOIRLab are, from the closest to the farthest, the SOAR telescope, Gemini South, and Vera C. Rubin Observatory, currently under construction. Once Rubin Observatory is complete it will scour the night sky using the largest digital camera ever fabricated for optical astronomy in an unprecedented, decade-long survey called the Legacy Survey of Space and Time (LSST). By surveying the entire night sky every few nights, Rubin Observatory will revolutionize our study of the changing Universe, shedding light on everything from the nature of dark matter to the structure and formation of our Milky Way. Rubin Observatory is a joint initiative of the National Science Foundation (NSF) and the US Department of Energy (DOE). Once completed, Rubin will be operated jointly by NSF’s …

15 March 2023: The nebula that keeps on giving, Messier 1 (Crab Nebula) is captured here by the Nicholas U. Mayall 4-meter Telescope from Kitt Peak National Observatory (KPNO), a Program of NSF’s NOIRLab. The storied history of this supernova remnant in modern astronomy begins when it was recorded in 1731 by British astronomer John Bevis, who believed it was nothing more than a cloudy blob. It was more than three decades later that French comet hunter Charles Messier clarified that the object was in fact something, and it became the first entry in his catalog of nebulae and star clusters. Then in the early 20th century astronomers connected Messier 1 to a supernova explosion observed by Chinese astronomers in 1054. This made the Crab Nebula the first astronomical object to be connected to a previously observed supernova. A pulsar — the ultra-dense, rapidly spinning remnant of a star — inside the Crab …

8 March 2023: Maunakea, the huge volcano in the background of this image, is one of the five volcanoes on the island of Hawai‘i. Maunakea is home to a number of astronomical observatories, including Gemini North, one half of the International Gemini Observatory, operated by NSF’s NOIRLab. It may not look like it, but this image was taken at night, not on a sunny afternoon as it might appear at first glance. The Moon reflects sunlight rather evenly across the visible spectrum, albeit at a brightness of only 0.3 lux — about 300,000 times fainter than the Sun. With a long exposure, moonlight can appear to illuminate scenery just as though it were a sunny day. If you look closely you might notice a few stars visible in the sky.

1 March 2023: From a dizzying height, the full scale and remoteness of the Gemini South telescope, one half of the International Gemini Observatory, operated by NSF's NOIRLab, can be realized. Located on the mountain Cerro Pachón at 2715 meters (8900 feet) above sea level, Gemini South benefits from the stable conditions of the local atmosphere. The dry air that eases the ‘seeing’ for the telescope is almost palpable above the sprawling Chilean Andes in the background. This image also captures the 8-meter mirror of the telescope peeking through the dome structure, an unusual event for the daylight hours, and the solar panels (bottom right), which power the telescope during the nocturnal observations of the southern skies. This aerial photo was taken as part of the recent NOIRLab 2022 Photo Expedition to all the NOIRLab sites.