ASTRONOMY - Stardust in Perseus

2023 January 12

Stardust in Perseus
Image Credit & Copyright: Jack Groves

Explanation: This cosmic expanse of dust, gas, and stars covers some 6 degrees on the sky in the heroic constellation Perseus. At upper left in the gorgeous skyscape is the intriguing young star cluster IC 348 and neighboring Flying Ghost Nebula with clouds of obscuring interstellar dust cataloged as Barnard 3 and 4. At right, another active star forming region NGC 1333 is connected by dark and dusty tendrils on the outskirts of the giant Perseus Molecular Cloud, about 850 light-years away. Other dusty nebulae are scattered around the field of view, along with the faint reddish glow of hydrogen gas. In fact, the cosmic dust tends to hide the newly formed stars and young stellar objects or protostars from prying optical telescopes. Collapsing due to self-gravity, the protostars form from the dense cores embedded in the molecular cloud. At the molecular cloud's estimated distance, this field of view would span over 90 light-years. 

ASTRONOMY - Spiral Aurora over Iceland

 2023 January 11

Spiral Aurora over Iceland
Image Credit & Copyright: Stefano Pellegrini

Explanation: The scene may look like a fantasy, but it's really Iceland. The rock arch is named Gatklettur and located on the island's northwest coast. Some of the larger rocks in the foreground span a meter across. The fog over the rocks is really moving waves averaged over long exposures. The featured image is a composite of several foreground and background shots taken with the same camera and from the same location on the same night last November. The location was picked for its picturesque foreground, but the timing was planned for its colorful background: aurora. The spiral aurora, far behind the arch, was one of the brightest seen in the astrophotographer's life. The coiled pattern was fleeting, though, as auroral patterns waved and danced for hours during the cold night. Far in the background were the unchanging stars, with Earth's rotation causing them to appear to slowly circle the sky's northernmost point near Polaris.

ASTRONOMY - Comet Leonard Closeup from Australia

 2022 January 12

Comet Leonard Closeup from Australia
Image Credit & Copyright: Blake Estes (itelescope.net)

Explanation: What does Comet Leonard look like up close? Although we can't go there, imaging the comet's coma and inner tails through a small telescope gives us a good idea. As the name implies, the ion tail is made of ionized gas -- gas energized by ultraviolet light from the Sun and pushed outward by the solar wind. The solar wind is quite structured and sculpted by the Sun's complex and ever changing magnetic field. The effect of the variable solar wind combined with different gas jets venting from the comet's nucleus accounts for the tail's complex structure. Following the wind, structure in Comet Leonard's tail can be seen to move outward from the Sun even alter its wavy appearance over time. The blue color of the ion tail is dominated by recombining carbon monoxide molecules, while the green color of the coma surrounding the head of the comet is created mostly by a slight amount of recombining diatomic carbon molecules. Diatomic carbon is destroyed by sunlight in about 50 hours -- which is why its green glow does not make it far into the ion tail. The featured image was taken on January 2 from Siding Spring Observatory in Australia. Comet Leonard, presently best viewed from Earth's Southern Hemisphere, has rounded the Sun and is now headed out of the Solar System.

ASTRONOMY - After Sunset Planet Parade

 2023 January 2

After Sunset Planet Parade
Image Credit & Copyright: Tunc Tezel (TWAN)

Explanation: Look up tonight and see a whole bunch of planets. Just after sunset, looking west, planets Venus, Saturn, Jupiter and Mars will all be simultaneously visible. Listed west to east, this planetary lineup will have Venus nearest the horizon, but setting shortly after the Sun. It doesn't matter where on Earth you live because this early evening planet parade will be visible through clear skies all around the globe. Taken late last month, the featured image captured all of these planets and more: the Moon and planet Mercury were also simultaneously visible. Below visibility were the planets Neptune and Uranus, making this a nearly all-planet panorama. In the foreground are hills around the small village of Gökçeören, Kaş, Turkey, near the Mediterranean coast. Bright stars Altair, Fomalhaut, and Aldebaran are also prominent, as well as the Pleiades star cluster. Venus will rise higher in the sky at sunset as January continues, but Saturn will descend.

ASTRONOMY - A Phoenix Aurora over Iceland

 2021 January 3

A Phoenix Aurora over Iceland
Image Credit & Copyright: Hallgrimur P. Helgason; Rollover Annotation: Judy Schmidt

Explanation: All of the other aurora watchers had gone home. By 3:30 am in Iceland, on a quiet September night, much of that night's auroras had died down. Suddenly, unexpectedly, a new burst of particles streamed down from space, lighting up the Earth's atmosphere once again. This time, surprisingly, pareidoliacally, the night lit up with an amazing shape reminiscent of a giant phoenix. With camera equipment at the ready, two quick sky images were taken, followed immediately by a third of the land. The mountain in the background is Helgafell, while the small foreground river is called Kaldá, both located about 30 kilometers north of Iceland's capital Reykjavík. Seasoned skywatchers will note that just above the mountain, toward the left, is the constellation of Orion, while the Pleiades star cluster is also visible just above the frame center. The 2016 aurora, which lasted only a minute and was soon gone forever -- would possibly be dismissed as an fanciful fable -- were it not captured in the featured, digitally-composed, image mosaic.

 2022 December 31

Moon over Makemake
Illustration Credit: Alex H. Parker (Southwest Research Institute)

Explanation: Makemake (sounds like MAH-kay MAH-kay), second brightest dwarf planet of the Kuiper belt, has a moon. Nicknamed MK2, Makemake's moon reflects sunlight with a charcoal-dark surface, about 1,300 times fainter than its parent body. Still, in 2016 it was spotted in Hubble Space Telescope observations intended to search for faint companions with the same technique used to find the small satellites of Pluto. Just as for Pluto and its satellites, further observations of Makemake and orbiting moon will measure the system's mass and density and allow a broader understanding of the distant worlds. About 160 kilometers (100 miles) across compared to Makemake's 1,400 kilometer diameter, MK2's relative size and contrast are shown in this artist's vision. An imagined scene of an unexplored frontier of the Solar System, it looks back from a spacecraft's vantage as the dim Sun shines along the Milky Way. Of course, the Sun is over 50 times farther from Makemake than it is from planet Earth.

ASTRONOMY - Horsehead and Flame

 2022 December 29

Horsehead and Flame
Image Credit & Copyright: Jason Close

Explanation: The Horsehead Nebula, famous celestial dark marking also known as Barnard 33, is notched against a background glow of emission nebulae in this sharp cosmic skyscape. About five light-years "tall" the Horsehead lies some 1,500 light-years away in the constellation of Orion. Within the region's fertile molecular cloud complex, the expanse of obscuring dust has a recognizable shape only by chance from our perspective in the Milky Way though. Orion's easternmost belt star, bright Alnitak, is to the left of center. Energetic ultraviolet light from Alnitak powers the glow of dusty NGC 2024, the Flame Nebula, just below it. Completing a study in cosmic contrasts, bluish reflection nebula NGC 2023 is below the Horsehead itself. This well-framed telescopic field spans about 3 full moons on the sky.

ASTRONOMY - Messier 88

 2022 December 28

Messier 88
Image Credit & Copyright: Adam Block, Mt. Lemmon SkyCenter, U. Arizona

Explanation: Charles Messier described the 88th entry in his 18th century catalog of Nebulae and Star Clusters as a spiral nebula without stars. Of course the gorgeous M88 is now understood to be a galaxy full of stars, gas, and dust, not unlike our own Milky Way. In fact, M88 is one of the brightest galaxies in the Virgo Galaxy Cluster some 50 million light-years away. M88's beautiful spiral arms are easy to trace in this sharp cosmic portait. The arms are lined with young blue star clusters, pink star-forming regions, and obscuring dust lanes extending from a yellowish core dominated by an older population of stars. Spiral galaxy M88 spans over 100,000 light-years.

ASTRONOMY - A Full Circle Rainbow over Norway

 2022 December 27

A Full Circle Rainbow over Norway
Image Credit & Copyright: Lukas Moesch

Explanation: Have you ever seen an entire rainbow? From the ground, typically, only the top portion of a rainbow is visible because directions toward the ground have fewer raindrops. From the air, though, the entire 360-degree circle of a rainbow is more commonly visible. Pictured here, a full-circle rainbow was captured over the Lofoten Islands of Norway in September by a drone passing through a rain shower. An observer-dependent phenomenon primarily caused by the internal reflection of sunlight by raindrops, the rainbow has a full diameter of 84 degrees. The Sun is in the exact opposite direction from the rainbow's center. As a bonus, a second rainbow that was more faint and color-reversed was visible outside the first.

ASTRONOMY - NGC 6164: Dragon's Egg Nebula and Halo

 2022 December 26

NGC 6164: Dragon's Egg Nebula and Halo
Image Credit & Copyright: Russell Croman

Explanation: The star at the center created everything. Known as the Dragon's Egg, this star -- a rare, hot, luminous O-type star some 40 times as massive as the Sun -- created not only the complex nebula (NGC 6164) that immediately surrounds it, but also the encompassing blue halo. Its name is derived, in part, from the region's proximity to the picturesque NGC 6188, known as the fighting Dragons of Ara. In another three to four million years the massive star will likely end its life in a supernova explosion. Spanning around 4 light-years, the nebula itself has a bipolar symmetry making it similar in appearance to more common planetary nebulae - the gaseous shrouds surrounding dying sun-like stars. Also like many planetary nebulae, NGC 6164 has been found to have an extensive, faint halo, revealed in blue in this deep telescopic image of the region. Expanding into the surrounding interstellar medium, the material in the blue halo was likely expelled from an earlier active phase of the O-star. NGC 6164 lies 4,200 light-years away in the southern constellation of the Carpenter's Square (Norma).