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Stereo Mars

Mars looks sharp in these two rooftop telescope views captured in late November from Singapore, planet Earth. At the time, Mars was about 82 million kilometers from Singapore and approaching its opposition, opposite the Sun in planet Earth’s sky on December 8. Olympus Mons, largest of the volcanoes in the Tharsis Montes region (and largest known volcano in the Solar System), is near Mars’ western limb. In both the images it’s the whitish donut-shape at the upper right. The dark area visible near center is the Terra Sirenum region while the long dark peninsula closest to the planet’s eastern limb is Sinus Gomer. Near its tip is Gale crater, the Curiosity rover’s landing site in 2012. Above Sinus Gomer, white spots are other volcanoes in the Elysium region. At top of the planet is the north polar cap covered with ice and clouds. Taken about two days apart, these images of the same martian hemisphere form a stereo pair. Look at the center of the frame and cross your eyes until the separate images come together to see the Red Planet in 3D. via NASA

Merging Galaxy Pair IIZw096

Bright at infrared wavelengths, this merging galaxy pair is some 500 million light-years away toward the constellation Delphinus. The cosmic mashup is seen against a background of even more distant galaxies, and occasional spiky foreground stars. But the galaxy merger itself spans about 100,000 light-years in this deep James Webb Space Telescope image. The image data is from Webb’s Near-InfraRed Camera (NIRCam) and Mid-InfraRed Instrument (MIRI). Their combined, sharp infrared view follows galactic scale restructuring in the dusty merger’s wild jumble of intense star forming regions and distorted spiral arms via NASA

Artemis 1: Flight Day 13

On flight day 13 (November 28) of the Artemis 1 mission the Orion spacecraft reached its maximum distance from Earth. In fact, over 430,000 kilometers from Earth its distant retrograde orbit also put Orion nearly 70,000 kilometers from the Moon. In the same field of view in this video frame from flight day 13, planet and large natural satellite even appear about the same apparent size from the uncrewed spacecraft’s perspective. Today (December 1) should see Orion depart its distant retrograde orbit. En route to planet Earth it will head toward a second powered fly by of the Moon. Splashdown on the home world is expected on December 11. via NASA

Supernumerary Rainbows over New Jersey

Yes, but can your rainbow do this? After the remnants of Hurricane Florence passed over the Jersey Shore, New Jersey, USA in 2018, the Sun came out in one direction but something quite unusual appeared in the opposite direction: a hall of rainbows. Over the course of a next half hour, to the delight of the photographer and his daughter, vibrant supernumerary rainbows faded in and out, with at least five captured in this featured single shot. Supernumerary rainbows only form when falling water droplets are all nearly the same size and typically less than a millimeter across. Then, sunlight will not only reflect from inside the raindrops, but interfere, a wave phenomenon similar to ripples on a pond when a stone is thrown in. In fact, supernumerary rainbows can only be explained with waves, and their noted existence in the early 1800s was considered early evidence of light’s wave nature. via NASA

Saturn at Night

Saturn is still bright in planet Earth’s night skies. Telescopic views of the distant gas giant and its beautiful rings often make it a star at star parties. But this stunning view of Saturn’s rings and night side just isn’t possible from telescopes closer to the Sun than the outer planet. They can only bring Saturn’s day into view. In fact, this image of Saturn’s slender sunlit crescent with night’s shadow cast across its broad and complex ring system was captured by the Cassini spacecraft. A robot spacecraft from planet Earth, Cassini called Saturn orbit home for 13 years before it was directed to dive into the atmosphere of the gas giant on September 15, 2017. This magnificent mosaic is composed of frames recorded by Cassini’s wide-angle camera only two days before its grand final plunge. Saturn’s night will not be seen again until another spaceship from Earth calls. via NASA

NGC 6744: Extragalactic Close Up

Beautiful spiral galaxy NGC 6744 is nearly 175,000 light-years across. That’s larger than the Milky Way. It lies some 30 million light-years distant in the southern constellation Pavo, with its galactic disk tilted towards our line of sight. This Hubble close-up of the nearby island universe spans about 24,000 light-years or so across NGC 6744’s central region. The Hubble view combines visible light and ultraviolet image data. The giant galaxy’s yellowish core is dominated by the visible light from old, cool stars. Beyond the core are star-forming regions and young star clusters scattered along the inner spiral arms. NGC 6744’s young star clusters are bright at ultraviolet wavelengths, shown in blue and magenta hues. Spiky stars scattered around the frame are foreground stars and well within our own Milky Way. via NASA

Earthset from Orion

Eight billion people are about to disappear in this snapshot from space. Taken on November 21, the sixth day of the Artemis 1 mission, their home world is setting behind the Moon’s bright edge as viewed by an external camera on the outbound Orion spacecraft. The Orion was headed for a powered flyby that took it to within 130 kilometers of the lunar surface. Velocity gained in the flyby maneuver will be used to reach a distant retrograde orbit around the Moon. That orbit is considered distant because it’s another 92,000 kilometers beyond the Moon, and retrograde because the spacecraft will orbit in the opposite direction of the Moon’s orbit around planet Earth. Orion will enter its distant retrograde orbit on Friday, November 25. Swinging around the Moon, Orion will reach a maximum distance (just over 400,000 kilometers) from Earth on Monday November 28 exceeding a record set by Apollo 13 for most distant spacecraft designed for human space exploration. via NASA

A Double Star Cluster in Perseus

Few star clusters this close to each other. Visible to the unaided eye from dark sky areas, it was cataloged in 130 BC by Greek astronomer Hipparchus. Some 7,000 light-years away, this pair of open star clusters is also an easy binocular target, a striking starfield in the northern constellation of the mythical Greek hero Perseus. Now known as h and chi Persei, or NGC 869 (above right) and NGC 884, the clusters themselves are separated by only a few hundred light-years and contain stars much younger and hotter than the Sun. In addition to being physically close together, the clusters’ ages based on their individual stars are similar – evidence that both clusters were likely a product of the same star-forming region. via NASA

The Butterfly Nebula from Hubble

Stars can make beautiful patterns as they age — sometimes similar to flowers or insects. NGC 6302, the Butterfly Nebula, is a notable example. Though its gaseous wingspan covers over 3 light-years and its estimated surface temperature exceeds 200,000 degrees C, the aging central star of NGC 6302, the featured planetary nebula, has become exceptionally hot, shining brightly in visible and ultraviolet light but hidden from direct view by a dense torus of dust. This sharp close-up was recorded by the Hubble Space Telescope and is processed here to show off remarkable details of the complex planetary nebula, highlighting in particular light emitted by oxygen (shown as blue), hydrogen (green), and nitrogen (red). NGC 6302 lies about 3,500 light-years away in the arachnologically correct constellation of the Scorpion (Scorpius). Planetary nebulas evolve from outer atmospheres of stars like our Sun, but usually fade in about 20,000 years. via NASA

Airglow Ripples over Tibet

Why would the sky look like a giant target? Airglow. Following a giant thunderstorm over Bangladesh in late April, giant circular ripples of glowing air appeared over Tibet, China, as pictured here. The unusual pattern is created by atmospheric gravity waves, waves of alternating air pressure that can grow with height as the air thins, in this case about 90-kilometers up. Unlike auroras powered by collisions with energetic charged particles and seen at high latitudes, airglow is due to chemiluminescence, the production of light in a chemical reaction. More typically seen near the horizon, airglow keeps the night sky from ever being completely dark. via NASA