Image of the Week

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 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 aerial 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.

22 February 2023: Kitt Peak National Observatory (KPNO), a Program of NSF’s NOIRLab, is shown here at dusk. In the foreground is the WIYN 0.9-meter Telescope while standing prominently on the far left hilltop is the Nicholas U. Mayall 4-meter Telescope. The pinkish band near the horizon is known as the Belt of Venus, an atmospheric phenomenon created by sunlight scattered in Earth’s atmosphere shortly after sunset, right above the Earth Shadow. NOIRLab operates the Mayall telescope on behalf of the US Department of Energy's Dark Energy Spectroscopic Instrument (DESI) survey. NOIRLab also hosts facilities belonging to a number of consortia that operate more than a dozen optical telescopes and two radio telescopes between them. KPNO is located 90 kilometers (56 miles) southwest of Tucson, Arizona, at an altitude of 2096 meters (6877 feet) in the Schuk Toak District on the Tohono O'odham Nation. This image was taken before the 2022 Contreras Fire, …

15 February 2023: Gemini North, one half of the International Gemini Observatory, operated by NSF’s NOIRLab, looks distinctly peculiar in this week’s Image of the Week. Photographs of the telescopes are often taken during the day, and so the telescope domes are closed in a lot of images. Even when the dome is open, only part of the dome is ajar. However, in this image, we see the entire top of the telescope directed at an object in the night sky! The photographer created this curious image by capturing a dozen images of the observatory as the dome turned a full 180 degrees and then stacking the images together. With this photographic trick, it appears the dome has become mysteriously transparent. The odd, brightly lit appearance of Gemini North is juxtaposed with the sprawling brilliance of the Milky Way overhead.

8 February 2023: The smudge in the center of this image from the Dark Energy Camera (DECam), built by the US Department of Energy, is the elusive dwarf galaxy Donatiello II. It is one of six dwarf galaxies discovered by Italian amateur astronomer Giuseppe Donatiello. Three of them — Donatiello II, III and IV — were tucked away in the DECam images, and are now known to be satellites of the Sculptor Galaxy (NGC 253) (outside the field, to the far right). DECam is an instrument on the Víctor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF’s NOIRLab. It combines a wide field of view with high sensitivity, meaning that it can scan large swathes of the night sky and also pick out the faint stars making up neighboring dwarf galaxies such as this one. The Milky Way shares its patch of the Universe with a whole …

1 February 2023: The beauty of the night sky is often a subtle one, but from the right location the Universe’s radiance truly emerges. Wide, clear skies perfect for exploration are luckily commonplace for Gemini South, the southern twin of the International Gemini Observatory, operated by NSF’s NOIRLab. This photo shows a brilliantly colored menagerie above and below Gemini South on Cerro Pachón. The telescope’s laser guide star system beams a column of light at the Milky Way. Our galaxy stretches like a belt across this photo, above the plethora of other objects. The most obvious of these are the Large and Small Magellanic Clouds at the bottom left of the center of the image. These galaxies are most conspicuous in the southern hemisphere and are easy to spot from Chile. Further to the left, near the horizon, is light generated from the nearby town of Andacollo. To the right of the …

25 January 2023: Maunakea, one of the volcanoes constituting the island of Hawai‘i, is an inactive shield volcano and one of the tallest mountains on Earth at an elevation of 4205 meters (13,786 feet). It’s home to Gemini North, one half of the International Gemini Observatory, operated by NSF’s NOIRLab. The summit of Maunakea makes for a fantastic astronomical observing location thanks to its high altitude, low humidity, and position far from and above most city lights. It’s also located above the tropical cloud cover that can obscure the view of the night sky around much of the rest of the island. The barren slopes of the volcano are clearly visible and if you zoom in you can see several telescopes, including Gemini North, on the snowy summit.

18 January 2023: As the Sun sets and its light scatters through Earth’s atmosphere, the Arizona sky glows in wondrous shades of vivid color. Kitt Peak National Observatory (KPNO), a Program of NSF’s NOIRLab, is the perfect location to enjoy these spectacular sunsets. Arid deserts, like the Arizona-Sonoran Desert where KPNO is located, display a clearer array of colors than areas where rain and humid weather are almost daily features. When heavy particles are present in the atmosphere, like water vapor, they absorb some of the sunlight and desaturate the colors. Through dry desert air, however, sunlight can pass unobstructed as it reaches our eyes. These natural conditions are helped by the clean air and low air pollution that are due to Arizona’s sparse population. For astronomers, the torrid, cleaner air enhances their ability to capture sharper data of the visible sky once the dark sets in. This photo was taken as part …

11 January 2023: The extent of our visual field is limited, and can process little information compared to its actual environment. But what would the night sky look like with a much wider field of view, like with a camera? In this panorama, the Milky Way sets the night ablaze in a bright glowing pillar, dividing the sky in two. On the right, the Gemini South telescope — one half of the International Gemini Observatory, operated by NSF’s NOIRLab — projects its laser guide star into the atmosphere. In the sky above the telescope, from left to right, lie the Small and Large Magellanic Clouds and the star Canopus. On the other end of the image is the SOAR Telescope — part of Cerro Tololo Inter-American Observatory, a Program of NOIRLab — with three stars above it forming the semblance of a triangle. The top left vertex is Denebola, the bottom Arcturus, …

4 January 2023: This observation captures the variable star HP Tau, which lies more than 550 light-years from Earth in the constellation Taurus. This image was created using data from the Nicholas U. Mayall 4-meter Telescope at Kitt Peak National Observatory (KPNO), a Program of NSF’s NOIRLab. HP Tau is a T Tauri star, a young and chaotic type of star that is settling into a more sedate phase of stellar life known as the main sequence. The length of time that a star spends on the main sequence will depend on its mass. Our Sun, for example, is about halfway through its roughly 10-billion-year main-sequence lifetime. HP Tau is part of a triple star system — the three separate stars are visible at the center of this image — surrounded by a large arcing reflection nebula. These nebulae, as the name suggests, reflect the light from nearby stars rather than glowing like …

28 December 2022: The Gemini North telescope, part of the International Gemini Observatory, operated by NSF’s NOIRLab, is located near the summit of Maunakea in Hawai‘i. This timelapse image captures Gemini North (second from the left) along with five other telescopes located near the summit. Maunakea is one of the five volcanoes that constitutes the island of Hawai‘i. The summit of Maunakea lies 4.2 kilometers (2.6 miles) above sea level, placing it above most of the tropical clouds and humidity of Hawai‘i. In contrast to the general climate of the island, the local environment near the summit can become snowy from time to time. Generally, little rain falls in the area and the soil is not suitable for most plant life. Low oxygen levels also make it a somewhat hazardous place to be for long periods of time. However, the unique conditions at Maunakea’s summit are also precisely what make its environment suitable …