The Ghosts of Gamma Cas

Gamma Cassiopeiae shines high in northern autumn evening skies. It's the brightest spiky star in this telescopic field of view toward the constellation Cassiopeia. Gamma Cas shares the ethereal-looking scene with ghostly interstellar clouds of gas and dust, IC 59 (top left) and IC 63. About 600 light-years distant, the clouds aren't actually ghosts. They are slowly disappearing though, eroding under the influence of energetic radiation from hot and luminous gamma Cas. Gamma Cas is physically located only 3 to 4 light-years from the nebulae. Slightly closer to gamma Cas, IC 63 is dominated by red H-alpha light emitted as hydrogen atoms ionized by the star's ultraviolet radiation recombine with electrons. Farther from the star, IC 59 shows proportionally less H-alpha emission but more of the characteristic blue tint of dust reflected star light. The cosmic stage spans over 1 degree or 10 light-years at the estimated distance of gamma Cas and friends.

from NASA https://ift.tt/4ySYgAa

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Lightning and Orion Beyond Uluru

What's happening behind Uluru? A United Nations World Heritage Site , Uluru is an extraordinary 350-meter high mountain in central Australia that rises sharply from nearly flat surroundings. Composed of sandstone , Uluru has slowly formed over the past 300 million years as softer rock eroded away. In the background of the featured image taken in mid-May, a raging thunderstorm is visible. Far behind both Uluru and the thunderstorm is a star-filled sky highlighted by the constellation of Orion. The Uluru region has been a home to humans for over 22,000 years. Local indigenous people have long noted that when the stars that compose the modern constellation of Orion first appear in the night sky, a hot season involving lightning storm s will soon be arriving. from NASA https://ift.tt/3uy2PLM

A Phoenix Aurora over Iceland

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, pareidolia cally, 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 Kald��, both located about 30 kilometers north of Iceland's capital Reykjav��k . 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 -...

Stephans Quintet from Webb, Hubble, and Subaru

OK, but why can't you combine images from Webb and Hubble? You can, and today's featured image shows one impressive result. Although the recently launched James Webb Space Telescope (Webb) has a larger mirror than Hubble, it specializes in infrared light and can't see blue -- only up to about orange. Conversely, the Hubble Space Telescope (Hubble) has a smaller mirror than Webb and can't see as far into the infrared as Webb, but can image not only blue light but even ultraviolet . Therefore, Webb and Hubble data can be combined to create images across a wider variety of colors. The featured image of four galaxies from Stephan's Quintet shows Webb images as red and also includes images taken by Japan 's ground-based Subaru telescope in Hawaii . Because image data for Webb , Hubble , and Subaru are made freely available, anyone around the world can process it themselves, and even create intriguing and scientifically useful multi-observatory montages...

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