Images of the Week 2024

6 March 2024: It is easy to assume that the deep void of outer space is completely dark, given the massive distances between celestial objects, but with the proper technique the truer count of all these objects becomes visible. Gemini North, one half of the International Gemini Observatory, operated by NSF’s NOIRLab, beholds this ethereal view of the brimming sky. With our naked eyes, we can see about 6000 stars, out of around 200 billion in the Milky Way. And this doesn’t even include the plethora of other astronomical objects! At the bottom of this image, the dense cloud deck below Gemini North’s position suppresses light pollution from neighboring cities. This blanket facilitates a substantially darker and clearer night, and light from fainter stars can more easily be captured. Appearing like a reflection of the clouds, the Milky Way itself is visible on the Hawaiian horizon. Also at the horizon, a bright band …

28 February 2024: Paradoxically, a truly dark sky isn’t pitch black. The darkest skies in the world, such as this one over Cerro Pachón, are actually theaters for a spectacular show of cosmic lights. Above Gemini South (right of center), half of the International Gemini Observatory operated by NSF’s NOIRLab, and Vera C. Rubin Observatory (right), a Program of NSF’s NOIRLab, the lights from stars, our galaxy, and atmospheric interplay are captured with a long exposure in this Image of the Week. Near the horizon is a hazy sea of faint red and green light known as airglow; this glow is caused by atomic processes in the Earth’s atmosphere. Our neighboring galaxies, the Small and Large Magellanic Clouds, are visible as blobs of light above the striped pole and the white post, respectively. Above Gemini South is the blooming Gum Nebula, the remains of a supernova whose red color is due to its …

21 February 2024: Do not be fooled by the seemingly artistic rendering of this image — the ombré colors painted across the sky above the snowy summit of Maunakea are all caused naturally by a phenomenon called Rayleigh scattering. As the day progresses and the Sun reaches the horizon, visible light has to pass through denser materials in the atmosphere. This scatters the light at longer wavelengths or in other words, redder light. This scattering creates spectacularly colorful views that anyone can see here on Earth. On the far right, Gemini North — one half of the International Gemini Observatory, operated by NSF’s NOIRLab — sits on the mountaintop against the vivid sunset and alongside several other observatories.

14 February 2024: The glittering Milky Way reaches over the UArizona Bok 2.3-meter Telescope at Kitt Peak National Observatory (KPNO), a Program of NSF’s NOIRLab. The Bok telescope was named after astronomer Bart Bok, a previous director of Steward Observatory, part of the University of Arizona. It is one of the largest optical telescopes at Kitt Peak operated solely by Steward Observatory. Within the band of the Milky Way, just right of the Bok telescope, the constellation Orion (The Hunter) can be identified by its distinctive three-star belt. Just below the belt is the Orion Nebula (Messier 42), marking Orion’s sword. To the right of Orion at a 45 degree angle is the constellation Taurus (The Bull), notable by its V-shape of bright stars. To the right of Taurus, ‘defended’ from Orion, are the Pleiades (the Seven Sisters), an open star cluster also known as Messier 45. The glowing red regions around these …

7 February 2024: This image shows Gemini North, one half of the International Gemini Observatory, operated by NSF’s NOIRLab, using a yellow-colored laser beam to adjust its adaptive optics system during the commissioning of its new TOPTICA laser in 2018. This laser emanates from just above the telescope and travels through Earth’s atmosphere to a layer roughly 90 kilometers (50 miles) up. There, it excites traces of sodium gas to produce a glowing ‘artificial star’ which is then used to sample the atmospheric turbulence at lower altitudes. This measurement allows the adaptive optics system to move deformable mirrors on the telescope to compensate for the turbulence. This system allows Gemini North to achieve images of stars, planets, and galaxies at resolutions that rival space-based telescopes. The laser may seem bright, but this is due to the long exposure of the picture — you can see the stars trailing across the night sky through …

31 January 2024: Gently rising above the horizon the Moon emerges, thinly veiled in the colors of Earth’s atmosphere. Although not apparent at first, a lunar eclipse is in the works; as the Moon glides “behind” the Earth, the Sun casts the shadow of Earth on the lunar surface. A lunar eclipse can last for several hours, and can be seen from anywhere on Earth where the Moon is above the horizon. This image was captured on 20 January 2019 from a high mountainous perch where Gemini North, one half of the International Gemini Observatory, operated by NSF's NOIRLab, is located in Hawai‘i. Being near the summit enabled not only a perfect view of this lunar eclipse, but also the bluish shadow of Maunakea beneath.

24 January 2024: Our home galaxy, the Milky Way, appears like a halo of light arching over the MDM Observatory’s Hiltner 2.4-meter Telescope at Kitt Peak National Observatory (KPNO), a Program of NSF’s NOIRLab. The whites of starlight and bluey black of shadowy trees feel commonplace on a dark night — but the reds in this image seem to cover the environment. What are the red clouds blooming in the sky? Why is there red light on the observatory? The red clouds are emission nebulae, clouds of gasses that have been so energized that they have lost some or all of their electrons. These gasses then emit light at various wavelengths, hence the name. These clouds look red because of the abundance of hydrogen. The largest of these blooms, located at the left end of the arch, is the Gum Nebula. What about the red lights on the ground? In order to function …

17 January 2024: Approximately as bright in the night sky as Proxima Centauri, this quiescent spiral galaxy known as NGC 1058 betrays its unassuming appearance with a record of supernovae and starburst activity. Captured by the Gemini Multi-Object Spectrograph (GMOS) at Gemini North, operated by NSF’s NOIRLab, the galaxy lies about 30 million light-years away in the constellation of Perseus as part of the NGC 1023 Group. A Seyfert Type 2 galaxy, NGC 1058 hosts a luminous center with a mix of blues and pinks along its arms that indicate active regions of star formation. Three supernovae have been observed in the galaxy: SN 1961V, SN 1969L, and SN 2007gr. SN 1961V has been enveloped in mystery as its explosion is yet to be understood. Although a faint shell of expanding gas can just be resolved by astronomers, some are skeptical because there is a remaining bright star near the position of its …

10 January 2024: The Rubin Auxiliary Telescope (AuxTel), with its open dome and deep red interior, looks to be inhabiting a little rocky planet floating through the expansive Milky Way galaxy in this image taken at Cerro Pachón in Chile. But in fact this image was created using a 360-degree panorama and composed into a photosphere image. The green and red light circling the horizon of the ‘planet’ is airglow, an atmospheric phenomenon caused when trace particles and gasses in the atmosphere become electrically charged or ionized. Their atoms emit light at various wavelengths when they recombine at night and faintly glow. The dark dust trails and red star-forming regions intertwined throughout the Milky Way are also prominently featured in this surreal view of the cosmos. Off in the distance, on the lower left side of the ‘planet’, the geometric dome of Vera C. Rubin Observatory, a Program of NSF’s NOIRLab, can be …

3 January 2024: Is that a cosmic crack in the sky? No, it’s just the colossal clouds of dust known as the Great Rift! In this stunning image of the Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF’s NOIRLab, the Great Rift’s dark clouds appear to slice the Milky Way’s river of starlight in half. Running vertically through this image, the Great Rift reminds us that our Milky Way is not simply a collection of stars. Our home galaxy is also host to a staggering amount of interstellar dust. In fact, the Great Rift alone contains a million Suns’ worth of it! This opaque cloud complex is made of ultrafine particles around ten times smaller than pollen. Despite their diminutive size, together they can obscure the light from the brightest part of our galaxy. Another ‘cloud’ of dust is also visible from this view. Running diagonally downward from the top left of …