Image of the Week

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’s 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’s 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’s 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’s 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’s 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’s 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’s 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’s 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’s 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’s 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’s 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 frame 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’s 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.

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.