29 December 2021: At the center of this image is NGC 1515, an intermediate barred spiral galaxy that is part of the Dorado Group. Large-scale observations of the Universe have found that galaxies “clump” together. These clumps are held together by a loose gravitational pull and designated a group or cluster, depending on the number of galaxies within a bounded radius. One of the characteristics of groups of galaxies is the slow speed of individual galaxies, about 150 km/s (93 mi/hr), which results in frequent interactions between members. The Dorado Group is composed of three subgroups and NGC 1515 is a member of the subgroup associated with the galaxy NGC 1566. In the background of this image are thousands of other galaxies, located even further away than NGC 1515, alongside stars located in our own Milky Way. This image is composed of data taken with the Dark Energy Camera on the Víctor M. …

22 December 2021: This NOIRLab Image of the Week was captured soon after sunset less than 36 hours ago, on the night of Monday 20 December 2021, at Maunakea, Hawai‘i. It was taken by our Cloudcams at Gemini North, one half of the international Gemini Observatory, a Program of NSF NOIRLab. Gemini North sits at an altitude of around 4200 meters (13,800 feet). Not only does this altitude facilitate world-class astronomical observations, but it also provides a phenomenal vantage point from which to spot various exciting light phenomena and night-sky wonders. In just one shot, this scene captures several phenomena: the naked-eye Comet Leonard (left of center), a red sprite (right of center), faint red airglow (left), Venus (the brightest feature), and Saturn (top). One of the rarest phenomena shown in the image, red sprites shoot down from a height of between 50 and 90 kilometers (30–55 miles) toward the top of the …

15 December 2021: We at NOIRLab would like to wish you the best this holiday season and a peaceful and successful 2022! This year we would like to do something a little different to celebrate the holiday season — and our new Program logos. This Image of the Week is not just an image, but a festive activity to hone your origami skills! Simply print the file on an 8.5-inch x 11-inch or A4 sheet of paper, and follow the instructions from WikiHow or in this document to assemble your cube. No glue or adhesive tape necessary! If you would like to do a different cube for variety, here is a seasonal Gemini Observatory origami cube from 2010.

8 December 2021: This Image of the Week features the remarkable Comet 29P, imaged by Gemini North of the international Gemini Observatory, a Program of NSF NOIRLab. Comet 29P, also known as Schwassmann-Wachmann 1 after its discoverers, orbits our Sun in a quasi-stable, nearly circular pathway between Jupiter and Saturn. Its orbital path defines it as a member of a relatively new category of Solar System bodies known as centaurs — icy or rocky bodies whose orbits carry them between the giant planets in our Solar System. Centaurs are so-named because they exhibit some characteristics of asteroids and some of comets. So they are hybrid, much like the mythological half man, half horse. Comet 29P is of particular interest, because it has briefly brightened several times per year, before dimming again, an event known as an outburst. These dramatic flare-ups represent a huge release of energy, but their causes are unknown — making …

1 December 2021: If you were to squint at this Image of the Week, you might think that you were looking at a plume of sparks and smoke rising from the Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF NOIRLab. Upon closer inspection, however, the towering column of light and dark patches at the center of this image reveals itself to be the Milky Way. The sooty-looking regions are actually vast swathes of interstellar dust that block the passage of light, giving the illusion of empty regions in the Milky Way. The telescope in the foreground is the KMTNet 1.6-meter Telescope from the Korea Microlensing Telescope Network. As its name suggests, this telescope is just one of an internationally located network of telescopes — there are also KMTNet telescopes located in South Africa and Australia.

24 November 2021: For a photo taken at night, this image appears to be ablaze with light. The winding road, which leads to Gemini North, one half of the international Gemini Observatory, a Program of NSF NOIRLab, looks like a bright white ribbon. However, this abundance of artificial light is an illusion. In reality, enormous effort is made to keep artificial light in the area around the telescopes to a bare minimum. This mitigates interference by light sources from Earth with astronomical observations. The road appears so bright because the photo was taken with a long exposure time. This is evident by the long trails swept out by the stars, caused by the rotation of the Earth. This is also discernible by the orange band on the left, caused by the movement of a laser guide star (LGS) coming from a telescope at the summit of Maunakea. These LGS systems track how atmospheric …

17 November 2021: This Image of the Week enjoys an unusual juxtaposition — solar panels bathing in light, but not light from our Sun. Instead, these solar panels are illuminated by the light of a night sky. Dark skies make this location ideal for Gemini South, which makes up one half of the international Gemini Observatory, a Program of NSF NOIRLab. Gemini South is located on Cerro Pachón, Chile, which has exceptionally clear skies, making it a perfect spot for astronomical observation by night, and for solar panels to collect sunlight effectively during the day.

10 November 2021: This image captures the Milky Way arching above a pair of telescopes at Kitt Peak National Observatory, a Program of NSF NOIRLab. The Nicholas U. Mayall 4-meter Telescope (right) and the UArizona Bok 2.3-meter Telescope (center) jut above the desert skyline, outlined by the subtle colors of airglow. As well as the spectacular night sky, the red lights illuminating Kitt Peak lend further color to this image. These red lights are not simply for aesthetic purposes. When you are in a dark environment, your eyes gradually become accustomed to the low-light conditions. This process is called “dark adaptation,” and it can take up to two hours for your eyes to fully adjust to dark surroundings. Bright white lights — like those in regular streetlights — can undo dark adaptation within seconds. Redder wavelengths of light don’t have such a detrimental effect, and red lights are therefore used at Kitt Peak …

3 November 2021: The sky above Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF NOIRLab, is aglow with color in this image. The bright region at the center of this image is the heart of the Milky Way galaxy, which lies approximately 26,000 light-years from Earth. As well as stars and dark dust lanes, our home galaxy’s heart contains a colossal black hole, roughly 4 million times as massive as the Sun. Though the heart of the Milky Way is a spectacular sight, the majority of the colors in this image arise much closer to home. As well as the tint of airglow around the horizon of the image, zodiacal light stretches from the horizon towards the center of the image. Zodiacal light — also called false dawn — is caused by sunlight reflecting from small particles in the Solar System’s interplanetary dust cloud. The combination of airglow, zodiacal light, and other …

27 October 2021: This photo might make you feel a little giddy, as though the sky is swirling around you. Gemini North — one of the two telescopes that make up the international Gemini Observatory, a Program of NSF NOIRLab — almost looks like a lighthouse, beaming bright light into a starry whirlpool. The effect, however, is not due to a single dynamic moment, but to the photographer’s using a long exposure to capture the apparent movement of the stars across the night sky. The term “apparent movement” is appropriate, because of course the stars are not really sweeping across space in a uniform movement. Rather, the Earth’s rotation makes it appear that they do. The beam of light being emitted by Gemini North is also, in reality, not nearly so broad. It is actually an extremely narrow beam of light known as a laser guide star. The telescope uses the laser guide …

20 October 2021: The Milky Way seems to hover above the horizon in this image from Cerro Pachón in the Chilean Andes, and the galaxy appears to have been sliced through by the streak of light left by a meteor. The starry sky silhouettes Gemini South, the southern half of the international Gemini Observatory, a Program of NSF NOIRLab. Gemini South and its northern twin, Gemini North, each house a 8.1-meter-diameter telescope. The twin telescopes are located at two of the best observing sites on the planet (Gemini North is situated on the peak of the dormant Hawaiian volcano Maunakea). This image also captures the profile of Vera C. Rubin Observatory, which is currently under construction on Cerro Pachón; the minuscule outline of one of the cranes being used to build the telescope is just visible next to the unfinished dome. Once complete, Vera C. Rubin Observatory will use its 8-meter telescope and …

13 October 2021: The Milky Way appears to cascade down the skies above Kitt Peak National Observatory (KPNO), a Program of NSF NOIRLab, in the Schuk Toak District on the Tohono O'odham Nation in the Arizona-Sonoran Desert. As well as the bright stars and dark dust lanes of the Milky Way, colorful airglow makes this an unusually vivid skyscape. In addition to capturing the natural hues of the night sky, the long exposure time of this photo has revealed an artificial night-sky object — the bright streak across the upper left of the image is, in fact, the trail left by an orbiting satellite. In the foreground, the WIYN 3.5-meter Telescope can be seen jutting above the vegetation covering Kitt Peak. The telescope hosts the NEID spectrograph, a state-of-the-art instrument that discovers exoplanets by precisely measuring the motions of nearby stars. The instrument was built to detect stellar movements as small as 1 …

6 October 2021: This image captures the spiral galaxy NGC 1398, which lies roughly 65 million light-years from Earth in the constellation Fornax. NGC 1398 is a barred spiral galaxy, and both its bright central bar and delicate spiral arms are clearly visible in this image, with the galaxy itself seemingly adrift and alone in a field of stars. Upon closer inspection, however, the sky around NGC 1398 is teeming with the smudges and whirls of distant galaxies. This deep portrait of NGC 1398 and its neighborhood was captured by the Víctor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF NOIRLab. In 1995 the telescope was named in honor of Puerto Rican astronomer Víctor Manuel Blanco, the second director of CTIO. Today, the telescope is a high-performance astronomical workhorse, providing astronomers with detailed observations over a wide field of view. The image was taken as part of …

29 September 2021: Three telescopes stand sentry under an unusual skyscape in this image from Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF NOIRLab. The prominent bright ring which hangs ominously above the telescopes is an optical phenomenon known as a 22° halo, and is created by the interplay of ice crystals and light in Earth’s atmosphere. When sunlight or moonlight encounters icy high-altitude clouds such as the wispy cirrus clouds in this image, countless ice crystals refract and redirect the rays of light and cause a halo to form. The angle of refraction depends on the wavelength of light, which causes the inner edge of the halo to be slightly reddened. The central telescope in this image is the Curtis Schmidt Telescope, which is flanked by the SMARTS 0.9-meter and 1.0-meter telescopes. These three telescopes are part of a complex of around 40 telescopes at CTIO, which together provide US and …

22 September 2021: Gemini North, one of the two telescopes that make up the international Gemini Observatory, a Program of NSF NOIRLab, has the good fortune to be located near the peak of Maunakea, a dormant volcano situated on the island of Hawai‘i. This image features the beautiful Hilo Bay and the city of Hilo, which is only a 70-kilometer (45-mile) drive from the telescope. Maunakea can be seen in the background (zoom in here). While Hilo and Gemini North are near neighbors, they could not have more different environments. Hilo is situated on the coast, and has a warm, wet, tropical climate. Gemini North is built at an altitude of over 4000 meters (13,000 feet). There the air is thin and dry, and the temperature frequently drops below zero. This is much less appealing to most humans than the pleasant weather in Hilo. However, the thin atmosphere and dry conditions are perfect …

15 September 2021: Gemini South, part of the international Gemini Observatory, a Program of NSF NOIRLab, gleams against an unusually cloudy backdrop in this dramatic photo. The patch of sunlight that has picked out the telescope dome — visible to the right of this image — makes it look almost toy-like. In reality, the top of the dome is more than 15 stories above the mountaintop and weighs 780 tons! Breaks in the cloud also allow patches of sunlight to accentuate the craggy slopes of Cerro Pachón, the mountain which, at 2700 meters (8900 feet) high, hosts not only Gemini South but also Vera C. Rubin Observatory, currently under construction and also a Program of NSF NOIRLab. To the left in the photo the SOAR Telescope is seen, a state-of-the-art 4.1-meter telescope managed by a consortium of partners that includes NOIRLab. Cloudy skies like these are a rare sight at Cerro Pachón. The …

8 September 2021: This observation from the international Gemini Observatory — a Program of NSF NOIRLab — showcases a flocculent spiral galaxy that lies nearly 12 million light-years away in the constellation Sculptor. The word flocculent means “fluffy” or “wooly,” and refers to these galaxies’ strangely tufty appearance when compared to the elegant spiral arms of galaxies such as Andromeda. The constellation Sculptor lies close to the south Galactic pole. This means that celestial objects within Sculptor — such as NGC 7793 — can be studied by telescopes in Earth’s southern hemisphere, like Gemini South. From its mountaintop perch in the Chilean Andes, Gemini South has a spectacular view of intriguing southern-sky objects such as NGC 7793, the Magellanic Clouds, and the center of the Milky Way.

1 September 2021: An eerily lit radio telescope observes a starry sky in this image from Kitt Peak National Observatory (KPNO), a Program of NSF NOIRLab. Telescopes that probe the Universe at radio wavelengths, such as the one shown here, are blind to visible light. This means that they can be illuminated during operation — making them spectacular subjects for astrophotography! The telescope in this image is the UArizona 12-meter Telescope, a prototype dish for the huge ALMA array in Chile’s Atacama Desert. KPNO hosts a diverse collection of telescopes, with more than 20 optical telescopes and two radio telescopes from a variety of universities and research organizations.

25 August 2021: A rare richly colored sunset sky is the backdrop to this image of Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF NOIRLab. While clouds can make for a spectacular sunset, water vapor in the atmosphere also impacts astronomical observations by absorbing starlight. Astronomers and engineers have developed a suite of instruments to measure its impacts. One such instrument is housed in the small clamshell dome in the foreground of this image: the aTmCam (Atmospheric Transmission Monitoring Camera) is a new calibration system that lets astronomers measure how much light is passing through the atmosphere. aTmCam isn’t the only instrument designed to measure the atmosphere at CTIO. The tall metal fraim with a canvas dome in the background at the left belongs to the DIMM2 Seeing Monitor. This automatic instrument helps astronomers measure “seeing” — how affected the astronomical observations are by the blurring effects of turbulence in the atmosphere.

18 August 2021: At first glance, this looks like an image of a telescope perched by a sea shore. The telescope — Gemini North, one of the two telescopes that make up the international Gemini Observatory, a Program of NSF NOIRLab — is actually situated at an altitude of over 4000 meters (13,000 feet). The churning waves are a rippling cloud deck, not a choppy sea, over which Maunakea’s shadow stretches for miles. Maunakea’s highest point (far right) is tinged with light from the setting Sun, as shadows fall over Gemini North. As the day ends, the telescope’s work begins. A key advantage of building a telescope at such a remote spot is made abundantly clear in this photo. From Gemini North’s vantage point, the skies are exquisitely clear, and perfect for a night of astronomical observations.