Image of the Week

13 March 2024: The stars are perfectly aligned in this image of the Southern Astrophysical Research (SOAR) Telescope, located on Cerro Pachón in Chile and operated by Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF NOIRLab. The Milky Way galaxy appears to be pouring out of the open dome and spilling across the colorful sky. The wash of yellow and green near the horizon is a mix of airglow and light pollution from nearby villages. Where the two colors transition, the Large Magellanic Cloud and Small Magellanic Cloud shine through (lower left). But near the center of this image is a truly notable grouping: the constellation Crux. Also known as the Southern Cross, it’s discoverable by its red star (the top of the cross) and three nearby blue stars that form a cross shape. This grouping of stars has been a beacon for both European and Pacific Islander navigators for centuries. Its …

6 March 2024: It is easy to assume that the deep void of outer space is completely dark, given the massive distances between celestial objects, but with the proper technique the truer count of all these objects becomes visible. Gemini North, one half of the International Gemini Observatory, operated by NSF NOIRLab, beholds this ethereal view of the brimming sky. With our naked eyes, we can see about 6000 stars, out of around 200 billion in the Milky Way. And this doesn’t even include the plethora of other astronomical objects! At the bottom of this image, the dense cloud deck below Gemini North’s position suppresses light pollution from neighboring cities. This blanket facilitates a substantially darker and clearer night, and light from fainter stars can more easily be captured. Appearing like a reflection of the clouds, the Milky Way itself is visible on the Hawaiian horizon. Also at the horizon, a bright band …

28 February 2024: Paradoxically, a truly dark sky isn’t pitch black. The darkest skies in the world, such as this one over Cerro Pachón, are actually theaters for a spectacular show of cosmic lights. Above Gemini South (right of center), half of the International Gemini Observatory operated by NSF NOIRLab, and Vera C. Rubin Observatory (right), a Program of NSF NOIRLab, the lights from stars, our galaxy, and atmospheric interplay are captured with a long exposure in this Image of the Week. Near the horizon is a hazy sea of faint red and green light known as airglow; this glow is caused by atomic processes in the Earth’s atmosphere. Our neighboring galaxies, the Small and Large Magellanic Clouds, are visible as blobs of light above the striped pole and the white post, respectively. Above Gemini South is the blooming Gum Nebula, the remains of a supernova whose red color is due to its …

21 February 2024: Do not be fooled by the seemingly artistic rendering of this image — the ombré colors painted across the sky above the snowy summit of Maunakea are all caused naturally by a phenomenon called Rayleigh scattering. As the day progresses and the Sun reaches the horizon, visible light has to pass through denser materials in the atmosphere. This scatters the light at longer wavelengths or in other words, redder light. This scattering creates spectacularly colorful views that anyone can see here on Earth. On the far right, Gemini North — one half of the International Gemini Observatory, operated by NSF NOIRLab — sits on the mountaintop against the vivid sunset and alongside several other observatories.

14 February 2024: The glittering Milky Way reaches over the UArizona Bok 2.3-meter Telescope at Kitt Peak National Observatory (KPNO), a Program of NSF NOIRLab. The Bok telescope was named after astronomer Bart Bok, a previous director of Steward Observatory, part of the University of Arizona. It is one of the largest optical telescopes at Kitt Peak operated solely by Steward Observatory. Within the band of the Milky Way, just right of the Bok telescope, the constellation Orion (The Hunter) can be identified by its distinctive three-star belt. Just below the belt is the Orion Nebula (Messier 42), marking Orion’s sword. To the right of Orion at a 45 degree angle is the constellation Taurus (The Bull), notable by its V-shape of bright stars. To the right of Taurus, ‘defended’ from Orion, are the Pleiades (the Seven Sisters), an open star cluster also known as Messier 45. The glowing red regions around these …

7 February 2024: This image shows Gemini North, one half of the International Gemini Observatory, operated by NSF NOIRLab, using a yellow-colored laser beam to adjust its adaptive optics system during the commissioning of its new TOPTICA laser in 2018. This laser emanates from just above the telescope and travels through Earth’s atmosphere to a layer roughly 90 kilometers (50 miles) up. There, it excites traces of sodium gas to produce a glowing ‘artificial star’ which is then used to sample the atmospheric turbulence at lower altitudes. This measurement allows the adaptive optics system to move deformable mirrors on the telescope to compensate for the turbulence. This system allows Gemini North to achieve images of stars, planets, and galaxies at resolutions that rival space-based telescopes. The laser may seem bright, but this is due to the long exposure of the picture — you can see the stars trailing across the night sky through …

31 January 2024: Gently rising above the horizon the Moon emerges, thinly veiled in the colors of Earth’s atmosphere. Although not apparent at first, a lunar eclipse is in the works; as the Moon glides “behind” the Earth, the Sun casts the shadow of Earth on the lunar surface. A lunar eclipse can last for several hours, and can be seen from anywhere on Earth where the Moon is above the horizon. This image was captured on 20 January 2019 from a high mountainous perch where Gemini North, one half of the International Gemini Observatory, operated by NSF NOIRLab, is located in Hawai‘i. Being near the summit enabled not only a perfect view of this lunar eclipse, but also the bluish shadow of Maunakea beneath.

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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 …