M45: 阿特拉斯和普勒俄涅的女儿们

M45: 阿特拉斯和普勒俄涅的女儿们

ByNASA中文

2023年1月5日 Messier 45: The Daughters of Atlas and Pleione Image Credit & Copyright: Stefan Thrun Explanation: Hurtling through a cosmic dust cloud a mere 400 light-years away, the lovely Pleiades or Seven Sisters open star cluster is well-known for its striking blue reflection nebulae. It lies in the night sky toward the constellation Taurus and the Orion Arm of our Milky Way galaxy. The sister stars are not related to the dusty cloud though. They just happen to be passing through the same region of space. Known since antiquity as a compact grouping of stars, Galileo first sketched the star cluster viewed through his telescope with stars too faint to be seen by eye. Charles Messier recorded the position of the cluster as the 45th…

火星与星团

火星与星团

ByNASA中文

2022年12月30日 Mars and the Star Clusters Image Credit & Copyright: Gabor Balazs Explanation: At this year’s end Mars still shines brightly in planet Earth’s night as it wanders through the head-strong constellation Taurus. Its bright yellowish hue dominates this starry field of view that includes Taurus’ alpha star Aldebaran and the Hyades and Pleiades star clusters. While red giant Aldebaran appears to anchor the V-shape of the Hyades at the left of the frame, Aldebaran is not a member of the Hyades star cluster. The Hyades cluster is 151 light-years away making it the nearest established open star cluster, but Aldebaran lies at less than half that distance, along the same line-of-sight. At the right, some 400 light-years distant is the open star cluster cataloged…

昴宿星团：七姐妹星团

昴宿星团：七姐妹星团

ByNASA中文

2022年12月5日 Pleiades: The Seven Sisters Star Cluster Image Credit & Copyright: Blake Estes (iTelescope Siding Spring Obs.) & Christian Sasse Explanation: Have you ever seen the Pleiades star cluster? Even if you have, you probably have never seen it as large and clear as this. Perhaps the most famous star cluster on the sky, the bright stars of the Pleiades can be seen with the unaided eye even from the depths of a light-polluted city. With a long exposure from a dark location, though, the dust cloud surrounding the Pleiades star cluster becomes very evident. The featured 11-hour exposure, taken from the Siding Spring Observatory in Australia, covers a sky area several times the size of the full moon. Also known as the Seven Sisters…

半圆顶上空的昴宿星团

半圆顶上空的昴宿星团

ByNASA中文

2022年7月19日 Pleiades over Half Dome Image Credit & Copyright: Dheera Venkatraman Explanation: Stars come in bunches. The most famous bunch of stars on the sky is the Pleiades, a bright cluster that can be easily seen with the unaided eye. The Pleiades lies only about 450 light years away, formed about 100 million years ago, and will likely last about another 250 million years. Our Sun was likely born in a star cluster, but now, being about 4.5 billion years old, its stellar birth companions have long since dispersed. The Pleiades star cluster is pictured over Half Dome, a famous rock structure in Yosemite National Park in California, USA. The featured image is a composite of 28 foreground exposures and 174 images of the stellar…

水星的钠尾

水星的钠尾

ByNASA中文

2022年5月3日 Mercury’s Sodium Tail Image Credit & Copyright: Sebastian Voltmer Explanation: That’s no comet. Below the Pleiades star cluster is actually a planet: Mercury. Long exposures of our Solar System’s innermost planet may reveal something unexpected: a tail. Mercury’s thin atmosphere contains small amounts of sodium that glow when excited by light from the Sun. Sunlight also liberates these molecules from Mercury’s surface and pushes them away. The yellow glow from sodium, in particular, is relatively bright. Pictured, Mercury and its sodium tail are visible in a deep image taken last week from La Palma, Spain through a filter that primarily transmits yellow light emitted by sodium. First predicted in the 1980s, Mercury’s tail was first discovered in 2001. Many tail details were revealed in…

七姐妹与加州星云

七姐妹与加州星云

ByNASA中文

2022年4月5日 Seven Sisters versus California Image Credit & Copyright: Neven Krcmarek Explanation: On the upper right, dressed in blue, is the Pleiades. Also known as the Seven Sisters and M45, the Pleiades is one of the brightest and most easily visible open clusters on the sky. The Pleiades contains over 3,000 stars, is about 400 light years away, and only 13 light years across. Surrounding the stars is a spectacular blue reflection nebula made of fine dust. A common legend is that one of the brighter stars faded since the cluster was named. On the lower left, shining in red, is the California Nebula. Named for its shape, the California Nebula is much dimmer and hence harder to see than the Pleiades. Also known as…

昴宿星团：七姐妹星团

昴宿星团：七姐妹星团

ByNASA中文

2021年11月24日 Pleiades: The Seven Sisters Star Cluster Image Credit & Copyright: Damien Cannane Explanation: Have you ever seen the Pleiades star cluster? Even if you have, you probably have never seen it as large and clear as this. Perhaps the most famous star cluster on the sky, the bright stars of the Pleiades can be seen without binoculars from even the depths of a light-polluted city. With a long exposure from a dark location, though, the dust cloud surrounding the Pleiades star cluster becomes very evident. The featured exposure, taken from Florida, USA, covers a sky area several times the size of the full moon. Also known as the Seven Sisters and M45, the Pleiades lies about 400 light years away toward the constellation of…

近乎月全食

近乎月全食

ByNASA中文

2021年11月20日 An Almost Total Lunar Eclipse Image Credit & Copyright: Robert Fedez Explanation: Predawn hours of November 19 found the Moon in partly cloudy skies over Cancun, Mexico. Captured in this telephoto snapshot, the lunar disk is not quite entirely immersed in Earth’s dark umbral shadow during a long partial lunar eclipse. The partial eclipse was deep though, deep enough to show the dimmed but reddened light in Earth’s shadow. That’s a sight often anticipated by fans of total lunar eclipses. Wandering through the constellation Taurus, the eclipsed Moon’s dimmer light also made it easier to spot the Pleiades star cluster. The stars of the Seven Sisters share this frame at the upper right, with the almost totally eclipsed Moon. Notable APOD Submissions (so far):…

醋山后方的火星与昴宿星团

醋山后方的火星与昴宿星团

ByNASA中文

2021年04月06日 Mars and the Pleiades Beyond Vinegar Hill Image Credit & Copyright: Kristine Richer Explanation: Is this just a lonely tree on an empty hill? To start, perhaps, but look beyond. There, a busy universe may wait to be discovered. First, physically, to the left of the tree, is the planet Mars. The red planet, which is the new home to NASA’s Perseverance rover, remains visible this month at sunset above the western horizon. To the tree’s right is the Pleiades, a bright cluster of stars dominated by several bright blue stars. The featured picture is a composite of several separate foreground and background images taken within a few hours of each other, early last month, from the same location on Vinegar Hill in Milford,…

火星、昴宿星团与仙女座星系

火星、昴宿星团与仙女座星系

ByNASA中文

2020年10月13日 Mars, Pleiades, and Andromeda over Stone Lions Image Credit & Copyright: Cem Özkeser Explanation: Three very different — and very famous — objects were all captured in a single frame last month. On the upper left is the bright blue Pleiades, perhaps the most famous cluster of stars on the night sky. The Pleiades (M45) is about 450 light years away and easily found a few degrees from Orion. On the upper right is the expansive Andromeda Galaxy, perhaps the most famous galaxy — external to our own — on the night sky. Andromeda (M31) is one of few objects visible to the unaided eye where you can see light that is millions of years old. In the middle is bright red Mars, perhaps…