Image of the Week

18 May 2022: A total lunar eclipse transformed the sky on the evening of 15 May 2022 and photographers at NOIRLab facilities in Arizona and Chile took advantage of clear skies to capture the event. This week’s Image of the Week shows the eclipse as seen from Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF’s NOIRLab, near La Serena, Chile. The crimson Moon shines above the Milky Way in the center left of the image. At the bottom of the image are the Víctor M. Blanco 4-meter Telescope (center) and Curtis Schmidt Telescope (left). In the southern hemisphere, the eclipse appeared extraordinarily dark as a result of the ash from the 2021 Hunga Tonga–Hunga Ha'apai volcanic eruption. In the northern hemisphere, the lunar eclipse was captured in this close-up image taken from the Visitor Center at Kitt Peak National Observatory (KPNO), also a Program of NSF’s NOIRLab, near Tucson, Arizona. You can …

11 May 2022: Shown here is the partial lunar eclipse of 19 November 2021 as seen from Kitt Peak National Observatory, a Program of NSF’s NOIRLab. This Image of the Week captures the eclipse above the Nicholas U. Mayall 4-meter Telescope in the Arizona-Sonoran Desert of Arizona. While technically a deep partial eclipse with 97% of the Moon in Earth’s shadow, or umbra, this eclipse was deep enough to give the Moon a pronounced red tint and decrease its brightness. The only light the Moon ever “shines” with is reflected sunlight. But while the Moon is within the umbra, the sunlight illuminating the Moon is scattered by Earth’s atmosphere. Essentially passing through a prism, the sunlight refracts in Earth’s atmosphere and takes on a crimson hue, which then illuminates the Moon. This hue can be seen in this image, taken on the same night through a 600-mm focal length camera lens (equivalent to …

4 May 2022: Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF's NOIRLab, is depicted here with the Milky Way and several nebulae within it, including the Lagoon Nebula and Rho Ophiuchi cloud complex. A number of CTIO telescopes are captured in this 360-degree panorama, including, from left to right: the UBC Southern Observatory, the SMARTS 1.0-meter Telescope, the Curtis Schmidt Telescope, the Víctor M. Blanco 4-meter Telescope, the SMARTS 1.5-meter Telescope and the SMARTS 0.9-meter Telescope. Various other, more unusual night sky phenomena are also visible. The white glow on the left of the image is zodiacal light, arising from interplanetary dust illuminated by the Sun. The green, orange, and reddish “clouds” near the horizon are airglow, caused by trace gasses in the upper atmosphere.

27 April 2022: Gemini North, one half of the international Gemini Observatory, a Program of NSF’s NOIRLab, uses a laser beam traveling through Earth’s atmosphere to adjust its adaptive optics. Like many large research telescopes today, Gemini North uses adaptive optics — bending its mirrors to compensate for atmospheric turbulence or “seeing”, which can blur the images of distant objects like stars and galaxies. The laser beam, seen here as a pink-orange stripe on the sky, travels into the upper atmosphere where it creates a bright spot of light that provides a reference point for the telescope to follow, and correct for, the atmospheric turbulence. This long-exposure photograph shows the laser tracking its target near the zenith, appearing to paint the sky with light. The stars appear as trails as they revolve around the north celestial pole during the long exposure.

20 April 2022: The aboveground portion of the McMath-Pierce Solar Telescope at Kitt Peak National Observatory (KPNO), a Program of NSF’s NOIRLab, is seen here at sunset. The McMath-Pierce Solar Telescope, located about 88 kilometers (55 miles) from Tucson, Arizona, saw its first light in 1962. It continued operating for an impressive 55 years until being decommissioned in 2017. For much of its life, it was the largest solar telescope on Earth. The McMath-Pierce telescope was unusual in that it used a large flat mirror called a heliostat to track the Sun across the sky and continually send sunlight down into an underground tunnel where the telescope itself was located. This helped to minimize hot air currents in the light path of the telescope, which would degrade the quality of the image. Though decommissioned, the McMath-Pierce Solar Telescope facility is being repurposed as the NOIRLab Windows on the Universe Center for Astronomy Outreach.

13 April 2022: This image, which looks a little like an enormous bubble in space, features a planetary nebula known as EGB 6. It was imaged by the Nicholas U. Mayall 4-meter Telescope at Kitt Peak National Observatory (KPNO), a Program of NSF’s NOIRLab. Planetary nebulae, notoriously, have nothing to do with planets. They form during the dying millennia of intermediate-mass stars, stars with masses between one and eight times the mass of the Sun. “Dying millennia” might sound like a very long time, but compared to the overall lifespan of a star, planetary nebulae are extremely short-lived. Towards the end of their life cycle, intermediate-mass stars enter the red giant phase, during which fusion reactions temporarily reignite in a dying star’s core. Layers of gas, shed or ejected during the red giant phase, absorb vast amounts of energy and create the gorgeous phenomena known as planetary nebulae. The dying millenia only last …

6 April 2022: The dust-filled center of our Milky Way galaxy stretches up from the Víctor M. Blanco 4-meter Telescope and one of the SMARTS Consortium telescopes at Cerro Tololo Inter-American Observatory (CTIO) in this Image of the Week. CTIO, a Program of NSF’s NOIRLab, is located at 2200 meters (7200 feet) in the mountains of Chile. Far from major cities, the dark landscape provides American, Chilean, and international researchers clear views of the southern sky. The spectacular green colors in the sky are not due to the aurora borealis, but instead are due to a phenomenon known as airglow. Airglow is not an optical illusion, but a genuine light source that results from chemical reactions in Earth’s upper atmosphere. It is far too faint to be visible during the daytime, and in most human-inhabited places it is drowned out by light pollution. However, out in the Chilean desert, it is possible to …

30 March 2022: Gemini North, of the international Gemini Observatory (a Program of NSF’s NOIRLab), stands peacefully in the foreground, under a crystal clear sky. The dramatic upward sweep of milky and sooty patches of the Milky Way galaxy is seen in the background. The dark tendrils that permeate the Milky Way are due to enormous clouds of cosmic dust. These clouds of tiny particles absorb and scatter light, making huge patches of the Milky Way appear dark to human eyes from our vantage point here on Earth. Telescopes such as Gemini North, however, see the night sky differently. They are designed to collect far more light that the human eye can, thanks to their large primary mirrors. They can also detect ranges of light that humans cannot, meaning that they can probe areas of cosmic dust, giving us information on things that would otherwise remain obscured.

23 March 2022: This Image of the Week captures the use of the laser guide star (LGS) on Gemini South, the southern twin of the international Gemini Observatory, a Program of NSF’s NOIRLab, during a night of observations on Cerro Pachón in the Chilean Andes. The LGS creates a constellation of five artificial stars, by causing sodium atoms 90 kilometers up in the atmosphere to glow. By tracking the atmosphere’s effect on these “stars”, the adaptive optics system within Gemini South can correct for distortions caused by turbulence in the atmosphere. These adjustments improve observations so much that a squiggle of light can become a distinct star, galaxy or other astronomical object. While it may seem that this laser must be shockingly powerful, it actually uses only 10–15 watts of energy, about the same as a bedside lamp. A similar LGS system is in use at Gemini North, which you can see in …

16 March 2022: The bright stars of the constellation Orion blaze in blue over Kitt Peak National Observatory (KPNO), a Program of NSF’s NOIRLab, in this image. They shine in stark contrast to the red lights lining the road approaching the observatory. The use of red lights might give this image a slightly otherworldly appearance, but they serve an important purpose: preserving the night vision of on-site staff and visitors. Red light preserves night vision better than other colors but is still bright enough to allow people to see what they are doing in a dark environment. It also interferes less with observing runs compared to blue or white light. The red lights look bright in this image, but that’s a result of the long exposure time used to capture the night sky. If you were at KPNO in person, the red lights would look far dimmer. In between the blue lights of …

9 March 2022: This Image of the Week features a sky speckled with stars and galaxies. The most prominent galaxy, in the upper right quadrant of the image, is known as NGC 1703. It was observed using the Dark Energy Camera (DECam), a high-performance camera installed by the US Department of Energy at the Víctor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF’s NOIRLab. NGC 1703 lies in a region of the sky that constitutes the constellation Dorado, the dolphinfish. You may know this fish by its Hawaiian name, mahi-mahi. The constellation was named Dorado back in the 16th century and the name was made official in the early 20th century. It is one of the 88 astronomical constellations recognized by the International Astronomical Union. So NGC 1703 could fancifully be thought of as one of the Dorado’s more impressive scales. Use the interactive zoom tool to …

2 March 2022: Reality seems to be reversed in this striking Image of the Week. It appears as though the telescopes of the Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF’s NOIRLab, are growing around the edge of a deep well of stars — or alternatively, as though the night sky is being reflected exceptionally crisply in a perfectly circular pool. This mind-bending effect is achieved by using a specialized camera lens called a fisheye. Fisheye lenses have a bulbous shape, which enables them to capture hemispherical images, but also causes the image to be significantly distorted — something that conventional lenses are designed to avoid. However, that distortion can be used to create striking effects such as the wraparound effect in this image, where the ground appears to have been scooped into a circle. Several of the telescopes housed at CTIO are visible around the edge of this image, including (clockwise …

23 February 2022: It’s difficult to believe that this photo was captured at nightime. The impressive peak of Maunakea — the dormant volcano that houses Gemini North, of the international Gemini Observatory, a Program of NSF’s NOIRLab — appears to be clearly lit under a bright blue sky. Shadows are even visible between the dormant volcano’s cracks and crevices. There are two clues that this image was actually taken at nighttime. First, the bright streaks in the sky are actually star trails — streaks of starlight, which appear when a photographer uses a long exposure. They are due to the Earth’s rotation on its own axis. The second clue is subtler. In the bottom left corner of the image, artificial lights can be seen. These lights would not be required in daytime. The overall brightness of the image is caused by such a long exposure time, so the camera had time to collect …

16 February 2022: This image captures not only Vera C. Rubin Observatory, a Program of NSF’s NOIRLab, but one of the celestial specimens Rubin Observatory will observe when it comes online: the Milky Way. The bright halo of gas and stars on the left side of the image highlights the very center of the Milky Way galaxy. The dark path that cuts through this center is known as the Great Rift, because it gives the appearance that the Milky Way has been split in half, right through its center and along its radial arms. In fact, the Great Rift is caused by a shroud of dust, which blocks and scatters visible light. This dust makes the Great Rift a difficult space to observe. Fortunately, Rubin is being built to conduct the Legacy Survey of Space and Time (LSST). This survey will observe the entire visible southern sky every few nights over the course …

9 February 2022: From the ground of the Kitt Peak National Observatory (KPNO), a Program of NSF’s NOIRLab, the Wisconsin-Indiana-Yale-NOIRLab (WIYN) 3.5-meter Telescope seemingly eyes the Milky Way as it spills from the horizon. A reddish airglow, a natural phenomenon, colors the horizon as well. KPNO is located in the Arizona-Sonoran Desert on the Tohono O'odham Nation and this clear view of part of the Milky Way’s galactic plane shows the favorable conditions in this environment that are needed to view faint celestial objects. These conditions, that include low levels of light pollution, a sky darker than a magnitude of 20, and dry atmospheric conditions, have allowed researchers in the WIYN Consortium to pursue observations of galaxies, nebulas, and exoplanets as well as many other astronomical targets using the WIYN 3.5-meter Telescope and its sibling telescope the WIYN 0.9-meter Telescope.

2 February 2022: The arms of the barred spiral galaxy NGC 1672 sweep across this Image of the Week, captured by the Víctor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF’s NOIRLab. NGC 1672 is something of a celestial mystery, as it is difficult to define its galactic activity. The nucleus is surrounded by a ring of hot gas filled with individual point sources of X-ray light, in other words bright, newly formed stars. However, the luminous nucleus of NGC 1672 itself shines brightly in various types of light from X-ray to infrared. Known as a Seyfert Type 2 nucleus, it’s an example of a specific type of active galactic nucleus (AGN) and likely a supermassive black hole. Fragile young stars and a destructive AGN shouldn’t necessarily be so close together, and their proximity in this galaxy creates a conundrum. Galaxies like NGC 1672 can open up …

26 January 2022: This image features a veritable panoply of telescopes, situated at the Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF's NOIRLab. In the foreground stands the Thai Southern Hemisphere Telescope, which forms part of Thai Robotic Telescope Network (TRTN) of The National Astronomical Research Institute of Thailand (NARIT). Five of the seven Panchromatic Robotic Optical Monitoring and Polarimetry Telescopes (PROMPT) are clustered in the background. However, you would be forgiven for overlooking the telescopes, given the truly extraordinary backdrop in this image — the Milky Way galaxy.

19 January 2022: In this extraordinary image, the Sun looks as though it's peeping out over a stormy, churning sea. In fact, the roiling waves are not made of liquid water, but are a spectacular cloud deck. We don’t typically see cloud decks from above, unless we’re in an airplane. This photo, however, was taken from a vantage point near to Gemini North, of the international Gemini Observatory, which is a Program of NSF’s NOIRLab. Gemini North is located near the summit of Maunakea, a dormant volcano that peaks at over 4200 meters (nearly 14,000 feet) above sea level. Gemini North’s very elevated location is perfect for astronomical observations, affording the high, dry and cold conditions that such telescopes love! It also occasionally provides astronomers and technicians with the opportunity to work above the clouds.

12 January 2022: This striking image centers on the decommissioned McMath-Pierce Solar Telescope, which is located at the Kitt Peak National Observatory (KPNO), a Program of NSF’s NOIRLab. The McMath-Pierce Solar Telescope saw first light in 1962, and continued operating for an impressive 55 years, until being decommissioned in 2017. For much of its life, it was the largest solar telescope on Earth. Observing the Sun might seem like a fairly straightforward task, given that one of the biggest challenges that astronomers typically face is collecting sufficient light from the very distant stars, planets, and galaxies that they wish to observe. In astronomical terms the Sun is very close to Earth, and it is by far the brightest object in our Solar System, so collecting sufficient light is indeed far less of a challenge. However, sunlight brings something in abundance that starlight does not — heat. Cooling is an enormous challenge for solar …

5 January 2022: Comet Leonard (C/2021 A1) has been beautifully captured soaring above Vera C. Rubin Observatory, a Program of NSF’s NOIRLab, in this early-evening Image of the Week taken in December 2021. The diffuse tail of Comet Leonard marks it apart from the stars, just left of center in the upper third of this image. Like other comets, its twin tails flow away from the Sun, as the solar radiation boils the icy body which then releases streams of dust and gas into space. Comet Leonard, which has an orbital period of 80,000 years, was the first comet discovered in 2021. Outbursts of gas since it was first observed and forward scattering of its reflected light also made it the brightest comet observed in 2021. It reached perihelion, its nearest distance to the Sun, on 3 January 2022. Unfortunately that was its last close approach to the Sun, as its current trajectory …