۱۳۹۲ بهمن ۲۴, پنجشنبه

Sunspot at Sunset



Image Credit & Copyright: Jo Hunter

Explanation: Reddened rays of the setting Sun flooded the skies over Cedar Creek Lake, southeast of Dallas, Texas, planet Earth on July 6th. And while sunsets may be the most watched celestial event, this one even offered something extra. A sunspot so large it was visible to the naked eye is captured in the serene sunset view, near the center of a solar disk dimmed and distorted by Earth's dense atomosphere. Telescopic views revealed the spot to be a complex of large solar active regions composed of sunspots, some larger than planet Earth itself.

The Terraced Night



Image Credit & Copyright: Cui Yongjiang

Explanation: Long after sunset on January 25 an unusually intense red airglow floods this south-looking skyscape. The scene was recorded with a long exposure using a digital camera over Yunnan Province in southwest China. At best faintly visible to the eye, the lingering airglow is due to chemiluminescence, the production of light through chemical excitation. Originating at an altitude similar to aurora, it can found around the globe. The chemical energy is initially provided by the Sun's extreme ultraviolet radiation On this night, despite the luminous atmosphere, the band of the Milky Way clearly stretches above the horizon with bright star Sirius near the top of the frame. Both airglow and starry sky are beautifully reflected in region's watery Yuanyang rice terraces below.

Night Hides the World



Image Credit & Copyright: Babak Tafreshi (TWAN)

Explanation: Stars come out as evening twilight fades in this serene skyscape following the Persian proverb "Night hides the world, but reveals a universe." In the scene from last November, the Sun is setting over northern Kenya and the night will soon hide the shores of Lake Turkana, home to many Nile crocodiles. That region is also known as the cradle of humankind for its abundance of hominid fossils. A brilliant Venus, then the world's evening star, dominates the starry night above. But also revealed are faint stars, cosmic dust clouds, and glowing nebulae along the graceful arc of our own Milky Way galaxy.

NGC 5101 and Friends



Image Credit & Copyright: Martin Pugh

Explanation: This sharp telescopic field of view holds two bright galaxies. Barred spiral NGC 5101 (top right) and nearly edge-on system NGC 5078 are separated on the sky by about 0.5 degrees or about the apparent width of a full moon. Found within the boundaries of the serpentine constellation Hydra, both are estimated to be around 90 million light-years away and similar in size to our own large Milky Way galaxy. In fact, if they both lie at the same distance their projected separation would be only 800,000 light-years or so. That's easily less than half the distance between the Milky Way and the Andromeda Galaxy. NGC 5078 is interacting with a smaller companion galaxy, cataloged as IC 879, seen just below and left of the larger galaxy's bright core. Even more distant background galaxies are scattered around the colorful field. Some are even visible right through the face-on disk of NGC 5101. But the prominent spiky stars are in the foreground, well within our own Milky Way.

The Heart and Soul Nebulas



Image Credit & Copyright: Leonardo Orazi
Explanation: Is the heart and soul of our Galaxy located in Cassiopeia? Possibly not, but that is where two bright emission nebulas nicknamed Heart and Soul can be found. The Heart Nebula, officially dubbed IC 1805 and visible in the above zoomable view on the right, has a shape reminiscent of a classical heart symbol. Both nebulas shine brightly in the red light of energized hydrogen. Several young open clusters of stars populate the image and are visible above in blue, including the nebula centers. Light takes about 6,000 years to reach us from these nebulas, which together span roughly 300 light years. Studies of stars and clusters like those found in the Heart and Soul Nebulas have focussed on how massive stars form and how they affect their environment


Rocket, Meteor, and Milky Way over Thailand




Image Credit & Copyright: Matipon Tangmatitham
Explanation: Can the night sky appear both serene and surreal? Perhaps classifiable as serene in the above panoramic image taken last Friday are the faint lights of small towns glowing across a dark foreground landscape of Doi Inthanon National Park in Thailand, as well as the numerous stars glowing across a dark background starscape. Also visible are the planet Venus and a band of zodiacal light on the image left. Unusual events are also captured, however. First, the central band of our Milky Way Galaxy, while usually a common site, appears here to hover surreally above the ground. Next, a fortuitous streak of a meteor was captured on the image right. Perhaps the most unusual component is the bright spot just to the left of the meteor. That spot is the plume of a rising Ariane 5 rocket, launched a few minutes before from Kourou, French Guiana. How lucky was the astrophotographer to capture the rocket launch in his image? Not lucky at all -- the image was timed to capture the rocket. What was lucky was how photogenic -- and perhaps surreal -- the rest of the sky turned out to be.

Clouds, Birds, Moon, Venus


Clouds, Birds, Moon, Venus
Image Credit & Copyright: Isaac Gutiérrez Pascual (Spain)
Explanation: Sometimes the sky above can become quite a show. In early September of 2010, for example, the Moon and Venus converged, creating quite a sight by itself for sky enthusiasts around the globe.   From some locations, though, the sky was even more picturesque. In the above image taken in Spain, a crescent Moon and the planet Venus, on the far right, were captured during sunset posing against a deep blue sky.   In the foreground, dark storm clouds loom across the image bottom, while a white anvil cloud shape appears above. Black specks dot the frame, caused by a flock of birds taking flight. Very soon after this picture was taken, however, the birds passed by, the storm ended, and Venus and the Moon set.   Bright Venus again becomes visible just after sunset this 2013 May and will appear near Jupiter toward the end of the month.