Image of the Week

24 January 2024: Our home galaxy, the Milky Way, appears like a halo of light arching over the MDM Observatory’s Hiltner 2.4-meter Telescope at Kitt Peak National Observatory (KPNO), a Program of NSF’s NOIRLab. The whites of starlight and bluey black of shadowy trees feel commonplace on a dark night — but the reds in this image seem to cover the environment. What are the red clouds blooming in the sky? Why is there red light on the observatory? The red clouds are emission nebulae, clouds of gasses that have been so energized that they have lost some or all of their electrons. These gasses then emit light at various wavelengths, hence the name. These clouds look red because of the abundance of hydrogen. The largest of these blooms, located at the left end of the arch, is the Gum Nebula. What about the red lights on the ground? In order to function …

17 January 2024: Approximately as bright in the night sky as Proxima Centauri, this quiescent spiral galaxy known as NGC 1058 betrays its unassuming appearance with a record of supernovae and starburst activity. Captured by the Gemini Multi-Object Spectrograph (GMOS) at Gemini North, operated by NSF’s NOIRLab, the galaxy lies about 30 million light-years away in the constellation of Perseus as part of the NGC 1023 Group. A Seyfert Type 2 galaxy, NGC 1058 hosts a luminous center with a mix of blues and pinks along its arms that indicate active regions of star formation. Three supernovae have been observed in the galaxy: SN 1961V, SN 1969L, and SN 2007gr. SN 1961V has been enveloped in mystery as its explosion is yet to be understood. Although a faint shell of expanding gas can just be resolved by astronomers, some are skeptical because there is a remaining bright star near the position of its …

10 January 2024: The Rubin Auxiliary Telescope (AuxTel), with its open dome and deep red interior, looks to be inhabiting a little rocky planet floating through the expansive Milky Way galaxy in this image taken at Cerro Pachón in Chile. But in fact this image was created using a 360-degree panorama and composed into a photosphere image. The green and red light circling the horizon of the ‘planet’ is airglow, an atmospheric phenomenon caused when trace particles and gasses in the atmosphere become electrically charged or ionized. Their atoms emit light at various wavelengths when they recombine at night and faintly glow. The dark dust trails and red star-forming regions intertwined throughout the Milky Way are also prominently featured in this surreal view of the cosmos. Off in the distance, on the lower left side of the ‘planet’, the geometric dome of Vera C. Rubin Observatory, a Program of NSF’s NOIRLab, can be …

3 January 2024: Is that a cosmic crack in the sky? No, it’s just the colossal clouds of dust known as the Great Rift! In this stunning image of the Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF’s NOIRLab, the Great Rift’s dark clouds appear to slice the Milky Way’s river of starlight in half. Running vertically through this image, the Great Rift reminds us that our Milky Way is not simply a collection of stars. Our home galaxy is also host to a staggering amount of interstellar dust. In fact, the Great Rift alone contains a million Suns’ worth of it! This opaque cloud complex is made of ultrafine particles around ten times smaller than pollen. Despite their diminutive size, together they can obscure the light from the brightest part of our galaxy. Another ‘cloud’ of dust is also visible from this view. Running diagonally downward from the top left of …

27 December 2023: Speeding towards Earth, meteors from the Geminid meteor shower streak across the sky above the Nicholas U. Mayall 4-meter telescope at Kitt Peak National Observatory (KPNO), a Program of NSF’s NOIRLab, in Arizona. Stretching across the center of the sky is the dusty arm of the Milky Way, arching over the radiant of the meteor shower in the constellation Gemini on the right. This image was captured during the peak of this year’s shower on 14 December 2023. The Geminid meteor shower is one of the most reliable meteor showers. Like other meteor showers, these fireballs are rocky particles zooming through our atmosphere and brightly burning until they disintegrate long before they hit the ground. The particles from the Geminids come from the asteroid 3200 Phaethon, unlike most meteor showers, which originate from comets. The Mayall telescope is the largest telescope at KPNO and is a great sight alongside the …

20 December 2023: It’s a snowy evening near the summit of Maunakea, Hawai‘i. One would expect traversing a dark, snowy mountaintop to be frightening, but the photographer here reveals a different perspective. With the clever use of a long exposure, the summit is vividly illuminated by a wide array of light, showing several telescopes. Gemini North, half of the International Gemini Observatory, operated by NSF’s NOIRLab, is situated at the center of the image. Long exposure times captures light streaks of passing vehicles, like the backlights of a car tracing the road leading to the summit, and the effect of Earth’s rotation, revealed by the stars sweeping in a circular motion around the celestial poles. With enough luck, it might even be possible to catch a meteor — like the one in the upper right quadrant of this image.

13 December 2023: Orbiting around the Milky Way about 210,000 light-years away is the Small Magellanic Cloud (SMC). This satellite galaxy is a dwarf galaxy, about a twentieth the size of our own galaxy. Sitting among its hundred million stars is a 'bauble' of hydrogen gas, captured here with the 4.1-meter Southern Astrophysical Research (SOAR) Telescope, one of the telescopes at Cerro Tololo Inter-American Observatory (CTIO), operated by NSF’s NOIRLab. This HII (pronounced H two) region is a cloud ripe with star formation. Young, hot, blue stars formed from the material in the molecular cloud, and now emit highly energetic ultraviolet radiation. The photons of the radiation field bombard the remaining hydrogen gas with energy that ionizes the atoms, or, in other words, excites them to a higher energy level. Astronomers use the term HII to refer to this ionized state of the hydrogen. Ionized hydrogen emits light at a specific wavelength called …

6 December 2023: We at NSF's NOIRLab would like to wish you the best this holiday season, and a peaceful and successful 2024! The background image is the nebula LBN 867, known as the Raspberry Nebula, located in the constellation Orion. It was captured 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. You can print and share your own copy of this card to wish others a happy holiday season in English and Spanish. Check out our animated holiday card here and download the image without text here. Happy Holidays, Felices Fiestas, and Mele Kalikimaka and Hau‘oli Makahiki Hou!

29 November 2023: The ‘way’ to the Universe begins at Cerro Tololo. In this incredible image, the Milky Way, which appears as a glowing cosmic road ascending to the heavens, seems to start at Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF’s NOIRLab. And indeed, the road towards understanding some cosmic phenomena does start at CTIO! Earlier this year, the SMARTS 1.5-meter Telescope (left) made the first confirmed detection of an extremely rare pair of stars that will someday become a kilonova. One of the most energetic events in the Universe, kilonovae are the explosions that result when two neutron stars merge. These astronomical events are so powerful that they can create heavy elements like gold and silver! So finding a progenitor system like this can shed more light on where heavy elements come from. The SMARTS 0.9-meter Telescope (right) helped answer the question: “How small can a star go?” In 2013, …

22 November 2023: With its swirling arms and luminous core, NGC 5364 is unmistakably a spiral galaxy, lying in the constellation Virgo. But it’s not just any spiral galaxy imaged 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. This eye-catching stellar body is classified as a grand design spiral galaxy. Grand design spiral galaxies are characterized by prominent, well-defined arms that circle outwards from a distinct core. Only ten percent of spiral galaxies are given this descriptive name and they are considered the archetype of spiral galaxies owing to their ‘perfect’ structure. However, NGC 5364 is not as perfect as it may appear. Compared to other grand design spirals, its arms are actually amorphous and asymmetrical. This distortion is thought to be due to interactions with the nearby lenticular galaxy NGC 5363, which can be seen in …

15 November 2023: While many know Hawai‘i for its tropical weather and volcanoes, at high altitudes winter storms can bring snow. This frequently falls atop Maunakea in Hawai‘i, one of five volcanoes that form the island of Hawai‘i. Maunakea (altitude 4200 meters, or about 14,000 feet) is home to the Gemini North telescope, part of the International Gemini Observatory, operated by NSF’s NOIRLab. Fortunately for Gemini North and the other telescopes located here, snowfall on Maunakea happens only a few times each winter. For the rest of the year, it is not uncommon for astronomers to look down and see nothing but an array of clouds below them.

8 November 2023: Founded in 1958, Kitt Peak National Observatory (KPNO), a Program of NSF’s NOIRLab, is home to one of the largest collections of optical and radio telescopes in the world. The 24 optical and two radio telescopes sit on Kitt Peak, the highest point in the Quinlan Mountains in the Arizona-Sonoran Desert on the Tohono Oʼodham Nation, 88 kilometers (55 miles) southwest of Tucson, Arizona. Of those telescopes, 13 are captured in this aerial image. In its 60 years of operation KPNO has set records and achieved many firsts. The Nicholas U. Mayall 4-meter Telescope (left), named after KPNO’s second director, Nicholas Ulrich Mayall, was the second-largest telescope in the world at the time of its construction in 1973. In 1976 Mayall was used to discover methane ice on Pluto. The oldest telescope at KPNO, the UArizona 0.9-meter Spacewatch Telescope, seen slightly below the Mayall telescope in this photo, houses the …

1 November 2023: IC 5148, nicknamed the Spare Tyre Nebula, is a beautiful planetary nebula located about 3000 light-years away near the ‘neck’ of the southern constellation Grus (The Crane). This image, captured with the Gemini South telescope, one half of the International Gemini Observatory operated by NSF’s NOIRLab, showcases the looming cloud of gas of IC 1548 and the central stellar remnant from which the gas radiates. It’s one of the fastest expanding planetary nebulae, pushing out into space at 180,000 kilometers per hour (112,000 miles per hour). With small telescopes, this nebula looks like a bright central star with an outer ring. The mesmerizing layers of gas are faint. They are almost undetectable without the use of larger telescopes, and not with the clarity captured in this image using the Gemini Multi-Object Spectrograph (GMOS) on Gemini South. Around the time IC 5148 was discovered by astronomers in 1894, researchers coined the …

25 October 2023: The dark skies of the Andean mountains come alive as a dazzling light show in this panorama of the Cerro-Tololo Inter-American Observatory (CTIO), a Program of NSF’s NOIRLab. Standing in the foreground are some of the observatory’s biggest telescopes: (left to right) the decommissioned CHilean Automatic Supernova sEarch (CHASE), the SMARTS 1-meter Telescope, the Curtis Schmidt Telescope, the Víctor M. Blanco 4-meter Telescope, the SMARTS 1.5-meter Telescope, and the SMARTS 0.9-meter Telescope. The sepia-like whites and browns of the ground-based observatory stand in contrast with the background, a colorful painting on the black canvas of space. While painters might use oil or watercolor, the medium of this painting is light itself. The thick impasto-style stroke at the center of this cosmic artwork is the Milky Way which appears as a textured arch of light. Plastered along the arch are dark patches collectively known as The Great Rift, colossal clouds of …

18 October 2023: Over the past two decades, the Gemini Near-Infrared Spectrograph (GNIRS) on the Gemini North telescope has peered into faraway quasars, ancient galaxies, and puzzling brown dwarfs. Now, this incredibly productive instrument of the International Gemini Observatory, operated by NSF's NOIRLab, is equipped with an integral field spectrograph. This upgrade effectively gives Gemini North ‘3D vision'. As illustrated in this infographic, GNIRS can now take a 2D field of view and extract a spectrum out of every pixel in near infrared. Standard spectroscopy would create this spectrum for only the entire field of view. This week’s Image of the Week shows the new spectroscopic capacity of GNIRS using NGC 6240 (nicknamed the Starfish Galaxy). The galaxy is a messy merger between two, maybe even three, smaller galaxies. At the center of the NGC 6240 are two distinct cores, seen in the infographic as two columns inside the spectrum. Studies have shown …

11 October 2023: From the vantage point of Gemini North, one half of the International Gemini Observatory, operated by NSF’s NOIRLab, a small rainbow can be seen sprouting from behind smaller peaks near the summit of Maunakea. One of the five volcanoes constituting the Big Island of Hawai‘i, Maunakea rises to an elevation of 4205 meters (13,786 feet). At that elevation, tropical clouds infrequently cover the summit, but they often roll past at lower altitude, as seen here, bringing some moisture to the dry area. These water droplets suspended in the air would typically be invisible, but their presence is betrayed when light is refracted through them. The droplets become like prisms, slowing and then separating the almost white sunlight into its component colors. The result is a spectacular spectrum of light — a rainbow — that is beautifully complimented by the red soil of the volcano and deep blue of the sky. …

4 October 2023: The summer of 2022 was a precarious time for Kitt Peak National Observatory (KPNO), a Program of NSF’s NOIRLab. On Saturday 11 June the Contreras Fire began on a remote ridge of the Baboquivari Mountains, south of Kitt Peak. The fire swept through the Tohono O’odham Nation, including the Quinlan Mountains where KPNO is located. The burnt trees seen here show how far the fire climbed yup the mountains, ending just feet away from the KPNO 2.1-meter Telescope, WIYN 0.9-meter Telescope, Visitor Center Levine 0.4-meter Telescope, and WIYN 3.5-meter Telescope (left to right). A few days after the fire began, the observatory was evacuated and KPNO staff worked quickly to shut down the scientific instruments. By the evening of 24 June the fire around KPNO had grown to almost 30,000 acres. Courageous fire crews subdued the fire on Kitt Peak by 28 June, allowing KPNO staff to evaluate the impact …

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 …