Astronomy fanatica

last SG · 2005-02-27T00:18:37+00:00

u'll find it on page 4 of this thread

poon cho tang SG

Astronomy Picture of the Day

2005 September 22

Orange Moon, Red Flash

Explanation: This remarkable telescopic image highlights the deep orange cast of a waning gibbous Moon seen very close to the eastern horizon earlier this week, on September 19. In fact, today's equinox at 22:23 UT marks the beginning of Fall in the Northern Hemisphere and makes this view from Stuttgart, Germany an almost Autumn Moon. While the long sight-line through the atmosphere filters and reddens the moonlight, it also bends different colors of light through slightly different angles, producing noticeable red (bottom) and green (top) lunar rims. Also captured here floating just below the Moon is a thin, red mirage (inset) -- in this case, an atmospherically magnified and distorted image of the red rim. Of course, this tantalizing lunar "red flash" is related to the more commonly seen green flash of the Sun.

Credit & Copyright: Stefan Seip

poon cho tang SG

Astronomy Picture of the Day

2005 September 23

Portrait of RY Tauri

Explanation: A star emerges from its natal cloud of gas and dust in this tantalizing portrait of RY Tauri, a small stellar nursery at the edge of the Taurus molecular cloud, a mere 450 light-years away. Illuminating a region that spans about 2/3 of a light-year, the youthful, central star is large, cool, and known to vary in brightness. Still collapsing, in a few million years the star's winds will likely clear out the gas and dust clouds, as it settles down to become a steady main sequence star like the Sun. What remains could well include a planetary system. The image data for RY Tauri is from the Gemini Observatory, on Mauna Kea, Hawaii -- based on observations proposed by the Astronomy Club of Dorval, Quebec.

Credit: Gemini Observatory, Club d'astronomie de Dorval, S. Cote (HIA), T. Rector (U. Alaska)

poon cho tang SG

Astronomy Picture of the Day

2005 September 25

WMAP Resolves the Universe

Explanation: Analyses of a new high-resolution map of microwave light emitted only 380,000 years after the Big Bang appear to define our universe more precisely than ever before. The eagerly awaited results announced last year from the orbiting Wilkinson Microwave Anisotropy Probe resolve several long-standing disagreements in cosmology rooted in less precise data. Specifically, present analyses of above WMAP all-sky image indicate that the universe is 13.7 billion years old (accurate to 1 percent), composed of 73 percent dark energy, 23 percent cold dark matter, and only 4 percent atoms, is currently expanding at the rate of 71 km/sec/Mpc (accurate to 5 percent), underwent episodes of rapid expansion called inflation, and will expand forever. Astronomers will likely research the foundations and implications of these results for years to come.

Credit: WMAP Science Team, NASA

poon cho tang SG

Astronomy Picture of the Day

2005 September 24

Cat's Eye

Explanation: Staring across interstellar space, the alluring Cat's Eye nebula lies three thousand light-years from Earth. A classic planetary nebula, the Cat's Eye (NGC 6543) represents a final, brief yet glorious phase in the life of a sun-like star. This nebula's dying central star may have produced the simple, outer pattern of dusty concentric shells by shrugging off outer layers in a series of regular convulsions. But the formation of the beautiful, more complex inner structures is not well understood. Seen so clearly in this sharp Hubble Space Telescope image, the truly cosmic eye is over half a light-year across. Of course, gazing into the Cat's Eye, astronomers may well be seeing the fate of our sun, destined to enter its own planetary nebula phase of evolution ... in about 5 billion years.

Credit: NASA, ESA, HEIC, and The Hubble Heritage Team (STScI / (AURA)

poon cho tang SG

Astronomy Picture of the Day

2005 September 26

Streams of Stars in the Virgo Cluster of Galaxies

Explanation: How do huge clusters of galaxies evolve? To help find out, astronomers pointed the wide-angle Burrell-Schmidt telescope on Kitt Peak National Observatory in Arizona, USA at the nearby Virgo Cluster of Galaxies. After hundreds of 15-minute exposures taken over two months in early 2004, the result is a dramatically deep and wide angle image of Virgo, the closest cluster of galaxies to our Milky Way Galaxy. Bright foreground stars have been digitally removed from the image but are still represented by numerous unusual dark spots. Inspection of the above image shows unusually large halos for the brightest galaxies as well as unusual faint streams of stars connecting Virgo galaxies that previously appeared unrelated. The above image allows a better reconstruction of the past few billion years of the gigantic Virgo cluster and illuminates the dynamics of clusters of galaxies in general.

Credit: C. Mihos (CWRU) et al., KPNO, NOAO, NSF

poon cho tang SG

Astronomy Picture of the Day

2005 September 27

The Star Pillars of Sharpless 171

Explanation: Towering pillars of cold gas and dark dust adorn the center star forming region of Sharpless 171. An open cluster of stars is forming there from the gas in cold molecular clouds. As energetic light emitted by young massive stars boils away the opaque dust, the region fragments and picturesque pillars of the remnant gas and dust form and slowly evaporate. The energetic light also illuminates the surrounding hydrogen gas, energize it to glow as a red emission nebula. Pictured above is the active central region of the Sharpless 171 greater emission nebula. Sharpless 171 incorporates NGC 7822 and the active region Cederblad 214, much of which is imaged above. The area above spans about 20 light years, lies about 3,000 light years away, and can be seen with a telescope toward the northern constellation of the King of Ethiopia (Cepheus).

Credit: Nicolas Outters (Observatoire d'Orange)

poon cho tang SG

Astronomy Picture of the Day

2005 September 28

A Rocket Launch at Sunset

Explanation: What kind of cloud is that? Last week, a sunset rocket launch lit up the sky and was photographed by sky enthusiasts as far as hundreds of miles away. The lingering result was a photogenic rocket plume. Not everyone who saw the resulting plume knew its cause to be a Minotaur rocket launched from Vandenberg Air Force Base in California, USA. The cloud was visible after sunset on 22 September. Fuel particles and water droplets expelled from the rocket swirled in the winds of the upper atmosphere, creating an expanding helix. The noctilucent plume was so high that it still reflected sunlight, where lower clouds in the foreground appeared dark. The above image also captured part of the plume reflecting sunlight as a rainbow or a colorful iridescent cloud. Below the launch plume is the planet Venus.

Credit & Copyright: Nick Hilton (fottostudio.com)

poon cho tang SG

Astronomy Picture of the Day

2005 September 29

An Unexplored Nebula

Explanation: The combined light of the stars of the Milky Way are reflected by this cosmic dust cloud that soars some 300 light-years above the plane of our Galaxy. Dubbed the Angel Nebula by astronomer Steve Mandel's 13 year old son, the dusty apparition is part of an expansive complex of dim and relatively unexplored diffuse nebulae, traced over large regions seen toward the North and South Galactic poles. Along with the blue tint characteristic of more commonly observed reflection nebulae, the Angel Nebula and other dusty galactic cirrus also produce a faint reddish luminescence, as dust grains convert the Milky Way's invisible ultraviolet radiation to visible red light. Spanning 3x4 degrees on the sky in the constellation Ursa Major, this wide-angle, high-resolution image was recorded as part of the Unexplored Nebula Project.

Credit & Copyright: Steve Mandel, Galaxy Images

poon cho tang SG

Astronomy Picture of the Day

2005 September 30

IC 1396 Close-Up

Explanation: Clouds of glowing hydrogen gas mingle ominously with dark dust lanes in this close-up of IC 1396, an active star forming region some 2,000 light years away in the constellation Cepheus. In this and other similar emission nebulae, energetic ultraviolet light from a hot young star strips electrons from the surrounding hydrogen atoms. As the electrons and atoms recombine they emit longer wavelength, lower energy light in a well known characteristic pattern of bright spectral lines. At visible wavelengths, the strongest emission line in this pattern is in the red part of the spectrum and is known as "Hydrogen-alpha" or just H-alpha. Part of IPHAS, a survey of H-alpha emission in our Milky Way Galaxy, this image spans about 20 light-years and highlights bright, dense regions within IC 1396, likely sites where massive new stars are born.

Credit: Nick Wright (University College London), IPHAS Collaboration

poon cho tang SG

Astronomy Picture of the Day

2005 October 1

NGC 613: Spiral of Dust and Stars

Explanation: When morning twilight came to the Paranal Observatory in Chile, astronomers Mark Neeser and Peter Barthel interrupted their search for faint quasars, billions of light-years away. And just for a moment, they used Very Large Telescopes at the European Southern Observatory to appreciate the beauty of the nearby Universe. One result was this stunning view of beautiful barred spiral galaxy NGC 613, a mere 65 million light-years away in the southern constellation Sculptor. Over 100 thousand light-years across, NGC 613 seems to have more than its fair share of spiral arms laced with cosmic dust clouds and bright star forming regions near the ends of a dominant central bar. Radio emission indicates the presence of a massive black hole at the center of NGC 613.

Credit: M. Neeser (Univ.-Sternwarte München), P. Barthel (Kapteyn Astron. Institute), H. Heyer, H. Boffin (ESO), ESO

poon cho tang SG

Astronomy Picture of the Day

2005 October 2

Magma Bubbles from Mt. Etna

Explanation: Mt. Etna erupted spectacularly in 2001 June. Pictured above, the volcano was photographed expelling bubbles of hot magma, some of which measured over one meter across. One reason planetary geologists study Earth's Mt. Etna is because of its likely similarity to volcanoes on Mars. Mt. Etna, a basalt volcano, is composed of material similar to Mars, and produces similar lava channels. Located in Sicily, Italy, Mt. Etna is not only one of the most active volcanoes on Earth, it is one of the largest, measuring over 50 kilometers at its base and rising nearly 3 kilometers high.

Credit & Copyright: Marco Fulle (Stromboli online)

poon cho tang SG

Astronomy Picture of the Day

2005 October 3

Saturn's Hyperion: A Moon with Odd Craters

Explanation: What lies at the bottom of Hyperion's strange craters? Nobody knows. To help find out, the robot Cassini spacecraft now orbiting Saturn swooped past the sponge-textured moon again last week and took an image of unprecedented detail. That image, shown above in false color, shows a remarkable world strewn with strange craters and a generally odd surface. The slight differences in color likely show differences in surface composition. At the bottom of most craters lies some type of unknown dark material. Inspection of the image shows bright features indicating that the dark material might be only tens of meters thick in some places. Hyperion is about 250 kilometers across, rotates chaotically, and has a density so low that it might house a vast system of caverns inside.

Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA

poon cho tang SG

Astronomy Picture of the Day

2005 October 4

The Milky Way in Stars and Dust

Explanation: The disk of our Milky Way Galaxy is home to hot nebulae, cold dust, and billions of stars. This disk can be seen from a dark location on Earth as a band of diffuse light across the sky. This band crosses the sky in dramatic fashion in the above series of wide angle sky exposures from Chile. The deepness of the exposures also brings to light a vast network of complex dust filaments. Dust is so plentiful that it obscures our Galaxy's center in visible light, hiding its true direction until discovered by other means early this century. The Galactic Center, though, is visible above as the thickest part of the disk. The diffuse glow comes from billions of older, fainter stars like our Sun, which are typically much older than the dust or any of the nebulae. One particularly photogenic area of darkness is the Pipe Nebula visible above the Galactic Center. Dark dust is not the dark matter than dominates our Galaxy -- that dark matter remains in a form yet unknown.

Credit & Copyright: Serge Brunier

poon cho tang SG

Astronomy Picture of the Day

2005 October 5

Annular Solar Eclipse at High Resolution

Explanation: On Monday, part of the Sun went missing. The missing piece was no cause for concern -- the Moon was only momentarily in the way. The event was not a total eclipse of the Sun for any Earth-bound sky enthusiast but rather, at best, an annular eclipse, where the Moon blocked most of the Sun. Because of the relatively large distance to the Moon during this Earth-Moon-Sun alignment, the Moon did not have a large enough angular size to block the entire Sun. Those who witnessed the solar eclipse from a narrow path through Spain and Africa, however, were lucky enough to see the coveted Ring of Fire, a dark Moon completely surrounded by the brilliant light of the distant Sun. Pictured above is a Ring of Fire captured two days ago in unusually high resolution above Spain. The resulting image shows details of the granular solar surface as well as many prominences around the Sun.

Credit & Copyright: Stefan Seip

poon cho tang SG

Astronomy Picture of the Day

2005 October 6

Spiral Galaxy NGC 1350

Explanation: This gorgeous island universe lies about 85 million light-years distant in the southern constellation Fornax. Inhabited by young blue star clusters, the spiral arms of NGC 1350 seem to join in a circle around the galaxy's large, bright nucleus - giving the galaxy the appearance of a limpid cosmic eye. NGC 1350 is about 130,000 light-years across making it as large or slightly larger than our own Milky Way. For earth-based astronomers, NGC 1350 is seen on the outskirts of the Fornax cluster of galaxies, but its estimated distance suggests that it is not itself a cluster member. The sharp image also reveals many background galaxies, some visible right through NGC 1350.

Credit: H. Boffin, H. Heyer, E.Janssen (ESO), FORS2, European Southern Observatory

poon cho tang SG

Astronomy Picture of the Day

2005 October 7

Eclipse Madrid

Explanation: A walk in the park seemed like a perfect idea to many enjoying a sunny October morning in Madrid, Spain. Of course, on October 3rd an added attraction was the Moon - seen in dramatic silhouette during an annular solar eclipse. This multiple exposure sequence follows the progress of the eclipse from Madrid's monument to King Alfonso XII in the pleasant Parque del Buen Retiro. The Sun rises at the left and moves up and to the right in the picture, with the ring-like annular phase near picture center. While a partial eclipse was visible over a wide area including Europe, Africa and western Asia, the central line of the shadow track crossed Madrid. Sun watchers in the capital city basked in an annular eclipse phase lasting about four minutes.

Credit & Copyright: Peter den Hartog

poon cho tang SG

Astronomy Picture of the Day

2005 October 8

Peculiar Arp 295

Explanation: A spectacular bridge of stars and gas stretches for nearly 250,000 light-years and joins this famous peculiar pair of galaxies cataloged as Arp 295. The cosmic bridge between the galaxies and the long tail extending below and right of picture center are strong evidence that these two immense star systems have passed close to each other in the past, allowing violent tides induced by mutual gravity to create the eye-catching plumes of stellar material. While such interactions are drawn out over billions of years, repeated close passages should ultimately result in the merger of this pair of galaxies into a larger single galaxy of stars. Although this scenario does look peculiar, galactic mergers are thought to be common, with Arp 295 representing an early stage of this inevitable process. The Arp 295 pair are the largest of a loose grouping of galaxies about 270 million light-years distant toward the constellation Aquarius. This deep color image of the region was recorded in September 2003 using the USNO 1 meter telescope near Flagstaff, Arizona.

Credit: Arne Henden (US Naval Observatory, Flagstaff)
Image Processed by Al Kelly

poon cho tang SG

Astronomy Picture of the Day

2005 October 9

Rollout of Soyuz TMA-2 Aboard an R7 Rocket

Explanation: It takes a big rocket to go into space. In 2003 April, this huge Russian rocket was launched toward Earth-orbiting International Space Station (ISS), carrying two astronauts who will make up the new Expedition 7 crew. Seen here during rollout at the Baikonur Cosmodrome, the rocket's white top is actually the Soyuz TMA-2, the most recent version of the longest serving type of human spacecraft. The base is a Russian R7 rocket, originally developed as a prototype Intercontinental Ballistic Missile in 1957. The rocket spans the width of a football field and has a fueled mass of about half a million kilograms. Russian rockets like this remain a primary transportation system to the International Space Station (ISS). Last week, a similar rocket successfully launched a spaceflight participant and two Expedition 12 astronauts to the space station.

Credit: Scott Andrews, NASA

poon cho tang SG

Astronomy Picture of the Day

2005 October 10

The Swirling Storms of Saturn

Explanation: Storms larger than hurricanes continually dot the upper atmosphere of the planet Saturn. A view of many storms occurring simultaneously was captured in July by the robot Cassini spacecraft now orbiting Saturn. An image of unusually high detail was made possible at that time when Cassini isolated a very specific color of polarized infrared light. The numerous white and dark spots visible above are the swirling storm systems. On Saturn, storms like these typically last for months and have even been seen merging. Bands of clouds that circle the entire planet are also clearly visible. Saturn's complex and majestic ring system is seen both in the foreground and the background. The above image has been digitally shortened along the vertical.

Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA

poon cho tang SG

Astronomy Picture of the Day

2005 October 11

NGC 869 & NGC 884: A Double Open Cluster

Explanation: Most star clusters are singularly impressive. Open clusters NGC 869 and NGC 884, however, are doubly impressive. Also known as "h and chi Persei", this unusual double cluster, shown above, is bright enough to be seen from a dark location without even binoculars. Although their discovery surely predates written history, the Greek astronomer Hipparchus notably cataloged the "double cluster". The clusters are over 7,000 light years distant toward the constellation of Perseus, but are separated by only hundreds of light years.

Credit & Copyright: Thomas V. Davis (tvdavisastropix.com)

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