Image of the Week

27 September 2023: This image, taken at sunrise, shows the blue shadow of Maunakea in Hawai‘i, home to the Gemini North telescope, tapering into an eerily symmetrical triangle. While Maunakea is vaguely triangular in shape, it is far from a perfect Euclidean pyramid, so why should the shadow appear so symmetrical? An identical triangular shadow phenomenon can be seen from the tops of many mountains or volcanoes at sunset or sunrise. The key to understanding this effect is that the viewer is staring down a lengthy ‘corridor’ of a sunrise (or sunset) shadow that reaches to the horizon. Even if the massive volcano were a perfect cube, a column, or really any other shape, the resulting shadow would appear to taper off at its summit as this part of the shadow extends far into the distance. You can see a similar effect with parallel railroad lines, hallways, or any other long and straight …

20 September 2023: Far, far away in the constellation Phoenix, two interacting galaxies meet in an epic battle spanning a hundred thousand light-years, captured here with the Víctor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF’s NOIRLab. Collectively known as NGC 454, the upper galaxy is a red elliptical galaxy called NGC 454 E, while below it is NGC 454 W, a blue, gas-rich irregular galaxy. Despite being in the early stages of their interaction, both galaxies already show severe distortion. Remnants of both galaxies have been stretched far beyond their main bodies, from the disarray of both galaxies’ stellar populations at the top right of this image to the globular clusters forming at NGC 454 W’s bottom-left side. Dust lanes from the dynamic interaction cross NGC 454 E, and NGC 454 W barely looks like the disk galaxy it was thought to be. The early merger …

13 September 2023: The bright band of the Milky Way seems to spill from the open dome of the Rubin Auxiliary Telescope (AuxTel) in this image from the recent NOIRLab 2022 Photo Expedition. As well as the spectacular Milky Way, replete with intricate clouds of gas and dust, an amorphous airglow is visible along both horizons. The AuxTel will take a variety of measurements and calibrations during the operations of Vera C. Rubin Observatory, a Program of NSF’s NOIRLab. These complementary data will be used to understand atmospheric conditions and make scientific observations more accurate as Rubin Observatory conducts its decade-long sky survey. In contrast to the new Simonyi Survey Telescope of Rubin Observatory, the AuxTel was repurposed for use at the observatory, a donation from astronomer Edgar Smith. Rubin Observatory is a joint initiative of the National Science Foundation and the US Department of Energy (DOE). Once completed, Rubin will be operated …

6 September 2023: Near the summit of Maunakea, Gemini North — the northern half of the International Gemini Observatory operated by NSF’s NOIRLab — sits high above the clouds of Hawai‘i in the company of other Maunakea observatories. Being at an altitude of approximately 4200 meters (nearly 14,000 feet) above sea level allows the telescope to capture amazing views of the world beyond Earth’s atmosphere. In addition, Gemini North’s location also grants it stable weather and atmospheric conditions for many nights a year, giving a perfectly clear picture of the sky. At such a high elevation, clouds often form below the summit to form a cloud deck. As is the case in this aerial image however, there are times when clouds accumulate higher in the sky above these facilities. Of course, a few high clouds will not stop astronomers from using Gemini North to make the most of their observations!

30 August 2023: The western horizon looks especially eye-catching in this image of the Nicholas U. Mayall 4-meter telescope at Kitt Peak National Observatory (KPNO), a Program of NSF’s NOIRLab. Beneath the glittering band of the Milky Way galaxy sprouts a cone of hazy, pastel light known as zodiacal light. This light shines along the ecliptic — the plane of our Solar System and the path of our Sun in the sky — meaning it appears just before dawn breaks or after dusk ends. With its soft white shine, the phenomenon is sometimes referred to as ‘false dawn’ or ‘false dusk’. However, unlike the reddish skies of true dawn and dusk which are caused by Earth’s atmosphere, the zodiacal light originates far beyond our planet: zodiacal light is caused by sunlight reflecting off interplanetary dust lying between the inner planets of our Solar System.

23 August 2023: The vantage point of the foothills of the Chilean Andes provides some of the best views of the night sky in the world, especially from Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF’s NOIRLab. Earth is oriented in such a way that most of the Milky Way can be seen on a clear night from the southern hemisphere, where CTIO is located. Beneath the oblique arms of our galaxy lie, left to right, the US Naval Observatory Deep South Telescope, DIMM1 Seeing Monitor, CHilean Automatic Supernova sEarch dome, aTmCam (straight back), SMARTS 1.0-meter Telescope, UBC Southern Observatory, and Curtis Schmidt Telescope . A noteworthy feature of this image is the Milky Way’s galactic center, which appears to set the galaxy itself ablaze. Despite the clouds of interstellar dust obscuring its light, it continues to shine with the light of millions of stars. From our point of view, the heart …

16 August 2023: The Milky Way and colorful celestial objects stretch over Kitt Peak National Observatory (KPNO), a Program of NSF’s NOIRLab, in this image of the WIYN 3.5-meter Telescope. This telescope is used to hunt for and characterize exoplanets with the NEID (pronounced NOO-id, rhymes with “fluid”) spectrograph, a state-of-the-art instrument for highly precise measurements of stellar movements. Above the WIYN telescope is a pantheon of constellations and their stellar companions. To the left, near the tree, is the brightest star in the sky, Sirius, that indicates the constellation Canis Major (the Great Dog). To its right is the constellation Orion (the Hunter) marked by the bright red supergiant star Betelgeuse of Orion’s ‘right shoulder’ and three inline stars that form his ‘belt’. The glowing red regions in the constellation are part of the Orion molecular cloud complex. Shockwaves from newly formed stars excite these and other areas of molecular hydrogen, which …

9 August 2023: In the constellation Sculptor lies this large extended spiral galaxy called NGC 289. Despite being around 75 million light-years away, the light of NGC 289 is stunningly captured here by the Dark Energy Camera (DECam) on the Víctor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF’s NOIRLab. The galaxy’s bluish arms reach through the expanse of space over 100,000 light-years, larger than the size of our own Milky Way. It’s classified as a Type II Seyfert galaxy with its ripe collections of star formation and bright core, but it’s also relatively faint. Studies have found that the galaxy contains large amounts of dark matter, which is a common feature of all galaxies with a low surface brightness. Dark matter is yet to be directly observed, which led the US Department of Energy to build the DECam in order to study the nature of dark …

2 August 2023: Beautiful sunsets often grace the telescopes of Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF’s NOIRLab. Pictured in this aerial image are the Víctor M. Blanco 4-meter Telescope (foreground), the SMARTS 1.5-meter, 0.9-meter, and 1.0-meter Telescopes, the Curtis Schmidt Telescope, and many more of the 40+ NOIRLab-operated telescopes in the foothills of the Chilean Andes. At 2200 meters (7200 feet) above sea level and in its relatively isolated position, Cerro Tololo is the perfect place to observe the southern skies. In fact, the summit takes its name from the way it drops away steeply on the northern side, as described by the local Indigenous Diaguita people. After 60 years of fruitful discoveries, CTIO continues to push the boundaries of astronomy with bountiful observations of the abyss up above.

26 July 2023: In this panorama, the Milky Way galaxy curves over the summit of Maunakea in Hawai‘i like an arched gateway to the cosmos. The 8.1-meter Gemini North, one half of the International Gemini Observatory, operated by NSF’s NOIRLab, is visible at the center of the image, and the University of Hawaii 2.2-meter telescope is to its right. From atop the long-dormant volcano, in the dry air of the Pacific, Gemini North and its neighboring telescopes are superbly located for infrared observations. The infrared capabilities of Gemini North — and its twin telescope Gemini South in the southern hemisphere — allow astronomers to see through the cosmic dust that blocks visible light from stars and galaxies. They are also optimal for peering into the cold corners of the Universe. Gemini North has detected the potential first traces of the Universe’s earliest stars, confirmed the presence of an ultra-faint fossil galaxy, and detected …

19 July 2023: Underneath the clear blue sky of Cerro Pachón ridge in Chile, construction continues on Vera C. Rubin Observatory, a Program of NSF’s NOIRLab. The 8.4-meter telescope is equipped with a 3.2-gigapixel camera — the world’s largest digital camera ever fabricated for optical astronomy — and is expected to see first light at the end of 2024. It will conduct an unprecedented, decade-long survey of the optical sky called the Legacy Survey of Space and Time (LSST). This survey will aim to capture nearly 1000 images of the sky every night. The observations will detect 10 million changes in the sky per night and over the survey’s ten-year timeline they will produce a 15-petabyte catalog database. Dedicated computer facilities will process Rubin Observatory data in real time, issuing worldwide public alerts within 60 seconds of any detected changes in the sky. This massive amount of astronomical data will be a game-changing …

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. …