Image of the Week

11 August 2021: The star-studded arch of the Milky Way dominates this striking skyscape from Kitt Peak National Observatory (KPNO), a Program of NSF’s NOIRLab. The subtle tones of airglow also lend some color to the image, and are visible as the shades of green and orange surrounding the domes. At the time of Kitt Peak’s construction in the late 1950s, many US observatories suffered from encroaching city lights and cloudy skies. Kitt Peak’s mountaintop location in Southern Arizona solved both problems, and was consequently chosen from more than 150 potential observing sites on mountain ranges across the US. KPNO is still providing astronomers with a pristine view of the night sky today, and hosts more than dozen optical telescopes as well as two radio telescopes.

4 August 2021: A riot of star trails dominate this striking image from Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF’s NOIRLab. Trails such as these are created when astrophotographers take long exposure images; they reveal the passage of the stars across the sky as the Earth rotates. The long exposure time of this photograph has also captured trails with a more down-to-earth origin! A nighttime staff member wearing a headlamp crossed the telescope platform while this photo was being taken. The long wavy streak threading between the telescopes was created by the regular bobbing of the passerby’s head as they walked, and the broader trail below it is the light they used to find their way.

28 July 2021: The Milky Way arches above a desert skyline in this image from Kitt Peak National Observatory (KPNO), a Program of NSF’s NOIRLab. The domes of the telescopes jut into the night sky, silhouetted by airglow and lights from the city of Tucson, 80 kilometers (50 miles) away. Only a solitary red light disturbs the darkness on Kitt Peak itself. This image shows a particularly striking view of the dust lanes threading through the Milky Way in the skies above the observatory. These dark bands of dust obscure our view of the Galactic Center at optical wavelengths, leaving astronomers dependent on observations from gamma-ray, x-ray, infrared, and radio telescopes. Kitt Peak National Observatory plays host to two radio telescopes and over twenty optical telescopes. The collection of optical telescopes still has plenty of work to do: astronomers use KPNO to study objects ranging from exoplanets to distant galaxies.

21 July 2021: The peak of the dormant volcano Maunakea, Hawai‘i, hosts some of the most advanced telescopes in the world, including Gemini North, which is the Northern half of the international Gemini Observatory, a Program of NSF’s NOIRLab. The thin atmosphere surrounding the telescopes is dry and cold, which is ideal for astronomical observations — and very unsuitable for people. It is remarkable to think that a mere 65 kilometers (40 miles) away, the beautiful town of Hilo nestles at Maunakea’s foot. Hilo is a little tricky to spot in this image, as it hides in the shade cast by the volcanoes surrounding it. If you look carefully, you can see the lights of the town next to the water. Hilo enjoys a tropical rainforest climate, with warm weather and heavy rain all year round. It could not be a more different environment from the one at the top of Maunakea, …

14 July 2021: This fisheye image captures the night sky as viewed from the desert scrubland of southern Arizona. The domes of Kitt Peak National Observatory, a Program of NSF’s NOIRLab, can be seen protruding from the rim of this image alongside the silhouettes of desert greenery. The fisheye lens creates the illusion that the night sky is a small circle, hemmed in by the horizon. The Milky Way arcs across the sky, its bright central band of stars threaded with dark lanes of dust. In addition to the subtle gloaming of the naturally occurring airglow, the image is lit up by the lights from neighboring towns, which can be seen on the horizon. Kitt Peak is home to one of the largest arrays of optical and radio telescopes in the world, with instruments from universities, the US Department of Energy, NASA, and NOIRLab.

7 July 2021: This image captures the elegant galaxy NGC 1365 in the Fornax Cluster of galaxies. Also known as The Great Barred Spiral Galaxy, NGC 1365 is a strikingly perfect example of a barred spiral galaxy. This image shows the galaxy’s prominent bar and its graceful spiral arms, with lanes of dust obscuring the extended diffuse glow of stars. The central bar of NGC 1365 influences star formation throughout the entire galaxy and conceals a supermassive black hole hidden behind multitudes of newly formed stars. Astronomers are interested in barred spiral galaxies like NGC 1365 for more than just their elegance — these galaxies provide insights into our home galaxy, the Milky Way, which is also a barred spiral galaxy. This image was built up using data from the Dark Energy Survey (DES), an ambitious project which mapped hundreds of millions of galaxies across the Universe using the Dark Energy Camera (DECam) …

30 June 2021: This glittering image captured by the Nicholas U. Mayall 4-meter Telescope at Kitt Peak National Observatory, a Program of NSF’s NOIRLab, shows the irregular dwarf galaxy Sextans A, which lies around 4.4 million light-years from Earth. This galaxy, which is only a fraction of the size of the Milky Way, has been contorted by successive waves of supernova explosions into the roughly square shape we see from Earth — a cosmic jewelry box filled with bright young stars. Sextans A is displayed in style in this gorgeous image, which showcases the irregular shape of this dwarf galaxy. Irregular galaxies such as Sextans A don’t have the regular appearance of spiral or elliptical galaxies, but instead display a range of weird and wonderful shapes. These galaxies are relatively small, and they are often susceptible to distortions resulting from close encounters or collisions with larger galaxies — sometimes leading to their irregular …

23 June 2021: Gemini North, one of the pair of telescopes that make up the international Gemini Observatory, a Program of NSF’s NOIRLab, stands in the foreground of this image with the Canada-France-Hawaii Telescope in the background. The domes appear poised to leap into the swirling blue of the sky. The whirlpool of stellar streaks is an illusion, however, known to astrophotographers as star trails. Just as the Sun progresses across the sky during the daytime, the Moon and stars progress across the sky at night. In both cases the reason is the same — the rotation of the Earth on its own axis. By observing the sky for an extended period of time, the paths of the stars are revealed. Here, the stars circle a single point in the sky, because the photographer angled his camera towards the north celestial pole.

16 June 2021: The gleaming dome of the Víctor M. Blanco 4-meter Telescope is flanked by two telescopes of the SMARTS Consortium in this image from Cerro Tololo Inter-American Observatory, a Program of NSF’s NOIRLab. Above the telescopes, the Large and Small Magellanic Clouds — two satellite galaxies that are neighbors to the Milky Way — hang over the scene. The starry band of the Milky Way itself streaks across the left hand side of the image, complete with dark lanes of dust. The vibrant colors of the night sky are due to the faint hues of airglow and the first hints of dawn. As well as tinting the night sky, the long exposure of this image and the rotation of the Earth have caused very small star trails to form. If you look closely at the upper corners of this image, you can spot the tell-tale streaks of long-exposure astrophotography.

9 June 2021: Vera C. Rubin Observatory basks under a cloudless sky in this image. The observatory is currently under construction atop Cerro Pachón in Chile. If you look closely, you can see a sliver of the teal-blue steel of the telescope structure within the nearly finished dome. Further sheets of the same blue steel are neatly stacked in the building site nearby. Beyond Cerro Pachón, the domes of Cerro Tololo Inter-American Observatory are visible on a nearby summit, and other ridges of the Andean foothills fade into blue in the distance. When complete, Rubin Observatory will use its 8.4-meter telescope and 3200-megapixel camera to conduct an unprecedented, multi-color, decade-long survey of the optical sky called the Legacy Survey of Space and Time (LSST). The camera will be the largest ever constructed for astronomy and will weigh almost 2800 kilograms — more than a rhinoceros!

2 June 2021: The night sky overflows with light and color in this long-exposure image from Kitt Peak National Observatory, a Program of NSF’s NOIRLab. The starry band of the Milky Way spans the upper left of the image, and the subtle reddish colors of airglow tint the sky in scarlet. The long exposure time allows the camera to collect sufficient light that the stars are picked out in sharp detail. However, that long exposure time also means that the lights from both the interior of the WIYN 0.9-meter Telescope’s dome and the distant city of Tucson in the far left appear to be very bright. In reality, artificial lights around the telescopes are tightly controlled, and the observatory is intentionally located far enough from human dwellings that there is limited light pollution. As well as producing a vibrant skyscape, this long exposure time has also stretched the stars at the top of …

26 May 2021: This image shows the planetary nebula Sh2-42 in the constellation Sagittarius, and was captured by using the SMARTS 0.9-meter Telescope at Cerro Tololo Inter-American Observatory, a Program of NSF’s NOIRLab. Despite the name, planetary nebulae have nothing to do with planets — they are spectacular funeral pyres formed by red giant stars at the end of their lives. As these giant stars expand and throw their outer gaseous layers into space, the hot exposed core of the star ionizes the surrounding material, causing it to glow in a range of vivid colours. As it reaches the end of its life, our own Sun is expected to form a planetary nebula — but not for another 5 billion years!

19 May 2021: In this image, one of the Maunakea observatories appears to be hanging by a golden thread. In reality, the thread is a beam of light, and it is not descending from the sky, but is pointing upwards from the telescope itself. It originates from Gemini North, part of the international Gemini Observatory, a Program of NSF’s NOIRLab. The light beam is a laser guide star , and its purpose is to form an artificial constellation of stars in the atmosphere, 90 kilometers (56 miles) from the Earth’s surface. Intuitively it seems that the laser beam must be extraordinarily powerful. Remarkably, however, the laser guide star produces about as much energy as a bedside lamp. The reason why light with so little energy can beam so far into the atmosphere is because laser beams are incredibly focused, with all the energy concentrated in a single direction. The laser beam is …

12 May 2021: This snapshot captures the towering Víctor M. Blanco 4-meter Telescope and one of the four SMARTS Consortium telescopes, both set against the spectacular backdrop of the early evening sky. The dome of the SMARTS 1.5-meter Telescope — which is actually gleaming white — has been illuminated in scarlet light, giving the observatory an unusually vivid appearance. This image was captured at Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF’s NOIRLab. The observatory’s high-altitude desert location — it lies 2200 meters (7200 feet) above sea level at the edge of Chile’s Atacama Desert — provides astronomers with the pristine conditions needed to observe the Universe.

5 May 2021: A beam of light shining into the night sky illuminated by moonlight. Its origin is Gemini North, one of the twin telescopes that make up the international Gemini Observatory, a Program of NSF’s NOIRLab. The light is in fact a laser guide star, and it serves a remarkable purpose. The laser guide star’s light encounters a layer of sodium high in the Earth’s atmosphere (about 90 kilometers (56 miles overhead) where it creates an artificial star. This artificial star is used as a reference by Gemini North, to allow the telescope to correct for much of the turbulence of Earth’s atmosphere. The artificial star is too faint to be seen by human eyes. The laser beam itself is visible, but not at large distances. So as striking as this image is, the inhabitants of Hawai‘i are not disturbed by a night sky filled with bright laser beams!

28 April 2021: In this striking image light from the Sun breaks over the craggy ridge at Kitt Peak National Observatory, a Program of NSF’s NOIRLab, silhouetting the 4-meter Nicholas U. Mayall Telescope and the tops of other telescope domes. Located at an altitude of 2096 meters (6877 feet) in southern Arizona, Kitt Peak hosts more than 20 telescopes for nighttime astronomy and daytime solar studies — making it one of the largest collections of astronomical instruments in the northern hemisphere. The eighteen-story Nicholas U. Mayall Telescope jutting above the ridge is a distinctive feature of the Kitt Peak skyline. It is the largest telescope at the observatory, and its tower and dome can be seen from over 80 kilometers (50 miles) away.

21 April 2021: This image of the week features the Telescope Mount Assembly of the 8.4-meter Simonyi Survey Telescope at Vera C. Rubin Observatory, currently under construction atop Cerro Pachón in Chile. This image shows the telescope frame prior to the mounting of the Top-End Assembly, a 28-metric tonne (31-ton) steel structure which was installed last month. Once the telescope is completed, the Top-End Assembly will support the telescope’s secondary mirror and the Rubin Observatory LSST Camera — the largest digital camera ever constructed for astronomy. The Simonyi Telescope will carry out the Rubin Observatory Legacy Survey of Space and Time (LSST), a 10-year observing campaign that will address some of the most pressing questions about the structure and evolution of the Universe.

14 April 2021: This image is so beautiful that it could almost be a painting, but it is real. It has been produced using observations made at the SMARTS 0.9-meter Telescope at the Cerro Tololo Inter-American Observatory (CTIO), which is a Program of NSF’s NOIRLab. It features a reflection nebula known as NGC 2626, which lies 3300 light-years from Earth. Reflection nebulae are not luminous themselves, but they reflect light from a nearby star or stars. The light scatters off the dust particles in the nebulae, which often results in reflection nebulae having a blue tint, because blue light scatters more efficiently. This is the same phenomenon that makes the sky on Earth appear blue — the laws of physics are the same throughout our Universe! The red nebulosities are glowing hydrogen gas.

7 April 2021: It looks as though the stars are falling through the sky above Gemini North, the northern-hemisphere-based half of the international Gemini Observatory, a Program of NSF’s NOIRLab. The stars, however, have not suddenly all shifted across the Universe. The trails of starlight are due to the movement of the Earth itself. We know that the Earth rotates once on its own axis every 24 hours, giving us daytime and nighttime, but it is still strange to see such a visual reminder. The photographer, Jason Chu, took a very long exposure in order to capture the changing view of the stars as the Earth rotated. The result is this spectacular image with the faint red glow of the Gemini North laser guide star system emanating from its open dome, the taillight of a passing car crossing the dark road below and sweeping star trails in the background.

31 March 2021: This gorgeous image resembles an inky patch of space that has been smudged by a giant celestial thumbprint. Actually the object is a planetary nebula named PN M 2-53. It was imaged using the Gemini North telescope of the international Gemini Observatory, a Program of NSF’s NOIRLab. Planetary nebulae have a wildly misleading name, as they have nothing to do with planets — or even exoplanets. The misnomer originates from the late 1700s, when astronomers thought that the gaseous structures resembled planets. Planetary nebulae are actually formed by some dying stars, right at the end of their lives. The layers of gas and dust shed by the dying stars are lit by their remaining cores, creating a planetary nebula. Despite its inaccuracy, the name has stuck!