Η διαστημική φωτογραφία της ημέρας - Αρχείο

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M82: Galaxy with a Supergalactic Wind
Credit: NASA, ESA, The Hubble Heritage Team, (STScI / AURA)
Acknowledgement: M. Mountain (STScI), P. Puxley (NSF), J. Gallagher (U. Wisconsin)

Explanation: What's lighting up the Cigar Galaxy? M82, as this irregular galaxy is also known, was stirred up by a recent pass near large spiral galaxy M81. This doesn't fully explain the source of the red-glowing outwardly expanding gas, however. Recent evidence indicates that this gas is being driven out by the combined emerging particle winds of many stars, together creating a galactic superwind.. The above photographic mosaic highlights a specific color of red light strongly emitted by ionized hydrogen gas, showing detailed filaments of this gas. The filaments extend for over 10,000 light years. The 12-million light-year distant Cigar Galaxy is the brightest galaxy in the sky in infrared light, and can be seen in visible light with a small telescope towards the constellation of the Great Bear (Ursa Major).

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A Lunar Eclipse on Solstice Day
Credit & Copyright: Jerry Lodriguss (Catching the Light)

Explanation: Sometime after sunset tonight, the Moon will go dark. This total lunar eclipse, where the entire Moon is engulfed in the shadow of the Earth, will be visible from all of North America, while the partial phase of this eclipse will be visible throughout much of the rest of the world. Observers on North America's east coast will have to wait until after midnight for totality to begin, while west coasters should be able to see a fully darkened moon before midnight. Pictured above is a digital prediction, in image form, for how the Moon and the surrounding sky could appear near maximum darkness. Rolling your cursor over the image will bring up labels. Parts of the Moon entering the circle labeled umbra will appear the darkest since the Sun there will be completely blocked by the Earth. Parts of the Moon entering the circle labeled penumbra will be exposed to some direct sunlight, and so shine by some degree by reflected light. The diminished glare of the normally full Moon will allow unusually good viewings of nearby celestial wonders such as the supernova remnant Simeis 147, the open star cluster M35, and the Crab Nebula M1. By coincidence this eclipse occurs on the day with the shortest amount of daylight in the northern hemisphere -- the Winter Solstice. This solstice eclipse is the first in 456 years, although so far it appears that no one has figured out when the next solstice eclipse will be.

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Tyrrhenian Sea and Solstice Sky
Credit & Copyright: Danilo Pivato

Explanation: Today the solstice occurs at 23:38 Universal Time, the Sun reaching its southernmost declination in planet Earth's sky. Of course, the December solstice marks the beginning of winter in the northern hemisphere and summer in the south. When viewed from northern latitudes, and as shown in the above horizontally compressed image, the Sun will make its lowest arc through the sky along the southern horizon. So in the north, the solstice day has the shortest length of time between sunrise and sunset and fewest hours of daylight. This striking composite image follows the Sun's path through the December solstice day of 2005 in a beautiful blue sky, looking down the Tyrrhenian Sea coast from Santa Severa toward Fiumicino, Italy. The view covers about 115 degrees in 43 separate, well-planned exposures from sunrise to sunset.

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Hidden Galaxy IC 342
Image Credit & Copyright: Ed Henry (Hay Creek Observatory)

Explanation: Similar in size to other large, bright spiral galaxies, IC 342 is a mere 7 million light-years distant in the long-necked, northern constellation Camelopardalis. A sprawling island universe, IC 342 would otherwise be a prominent galaxy in our night sky, but it is almost hidden from view behind the veil of stars, gas and dust clouds in the plane of our Milky Way galaxy. Even though IC 342's light is dimmed by intervening cosmic clouds, this remarkably sharp telescopic image traces the galaxy's own obscuring dust, blue star clusters, and glowing pink star forming regions along spiral arms that Wind far from the galaxy's core. IC 342 may have undergone a recent burst of star formation activity and is close enough to have gravitationally influenced the evolution of the local group of galaxies and the Milky Way.

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The Solstice Moon's Eclipse
Image Credit & Copyright: Chris Hetlage

Explanation: A big, bright, beautiful Full Moon slid into planet Earth's shadow early Tuesday morning. Remarkably, the total lunar eclipse coincided with the date of the December Solstice. During the eclipse, the best viewing in North America found the coppery lunar disc high in a cold winter sky, the Moon reddened by light filtering into the Earth's dark central shadow or umbra. The light comes from all the sunsets and sunrises, seen from a lunar perspective around the edges of a silhouetted Earth. Passing closer to the center of the umbra, the Moon's southern hemisphere (left) appears darker in this eclipse image, recorded from Deerlick Astronomy Village, Georgia, USA. The picture is a digital composite, a separate longer exposure added to an eclipse frame to capture the surrounding star field.

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Σχόλιο : Είναι μία από τις μεγαλύτερες σε διαστάσεις φωτογραφία, που έχει στείλει η NASA στο APOD.

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Star Trails in the North
Image Credit & Copyright: P-M Hedén (Clear Skies, TWAN)

Explanation: Pointing skyward, the wall of this ruined Viking church still stands after a thousand winters, near the town of Vallentuna, Sweden. The time exposure records the scene on December 14th as stars leave graceful arcing trails during a long night, reflecting planet Earth's daily rotation on its axis. The Earth's axis points toward Polaris, the North Star, near the center of the concentric trails. Welcomed by skygazers on this winter's night, a bright meteor from the annual Geminid meteor shower also flashes through the frame. The meteor cuts across the star trails just above the lower church wall. Contributing to the beautiful composition, meteor streak and church apex both gesture toward the North Celestial Pole.

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Decorating the Sky
Image Credit & Copyright: Rogelio Bernal Andreo

Explanation: Bright stars, clouds of dust and glowing nebulae decorate this cosmic scene, a skyscape just north of Orion's belt. Close to the plane of our Milky Way Galaxy, the wide field view spans about 5.5 degrees. Striking bluish M78, a reflection nebula, is at the left. M78's tint is due to dust preferentially reflecting the blue light of hot, young stars. In colorful contrast, the red sash of glowing hydrogen gas sweeping through the center is part of the region's faint but extensive emission nebula known as Barnard's Loop. At right, a dark dust cloud forms a prominent silhouette cataloged as LDN 1622. While M78 and the complex Barnard's Loop are some 1,500 light-years away, LDN 1622 is likely to be much closer, only about 500 light-years distant from our fair planet Earth.

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Sideways Orion Over Snowy Ireland
Credit & Copyright: Brendan Alexander (Donegal Skies)

Explanation: Orion always comes up sideways ... and was caught in the act earlier this month by over a snowy landscape in Donegal, Ireland. To compose this serene picture, the photographer found a picturesque setting to the east, waited until after sunset, and then momentarily lit the foreground with a flashlight. The three bright stars in Orion's belt stand in a nearly vertical line above the snow covered road at the bottom. Hanging from his belt, the stars and nebulae of the Hunter's sword are visible lower and to the right. Yellow-orange Betelgeuse is the brightest star on the image left. As winter progresses in Earth's northern hemisphere, Orion will rise earlier and so appear continually higher in the sky at sunset.

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One Million Galaxies
Credit: 2MASS, T. H. Jarrett, J. Carpenter, & R. Hurt

Explanation: Are the nearest galaxies distributed randomly? A plot of over one million of the brightest "extended sources" detected by the Two Micron All Sky Survey (2MASS) shows that they are not. The vast majority of these infrared extended sources are galaxies. Visible above is an incredible tapestry of structure that provides limits on how the universe formed and evolved. Many galaxies are gravitationally bound together to form clusters, which themselves are loosely bound into superclusters, which in turn are sometimes seen to align over even larger scale structures. In contrast, very bright stars inside our own Milky Way Galaxy cause the vertical blue sash.

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Skylights Over Libya
Credit & Copyright: Tunç Tezel (TWAN)

Explanation: Sometimes the sky itself seems to glow. Usually, this means you are seeing a cloud reflecting sunlight or moonlight. If the glow appears as a faint band of light running across the whole sky, you are probably seeing the combined light from the billions of stars that compose our Milky Way Galaxy. Such a glow is visible rising diagonally up to the right in the above image. If the glow is seen coming up from the horizon just before sunrise or just after sunset, however, you might be seeing something called zodiacal light. Pictured rising diagonally up to the left in the above image, zodiacal light is just sunlight reflected by tiny dust particles orbiting in our Solar System. Many of these particles were ejected by comets. The above image was taken just after sunset earlier this month from Ras Lanuf, Libya.

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Eclipse at Moonset
Image Credit & Copyright: Itahisa N. González (Grupo de Observadores Astronómicos de Tenerife)

Explanation: Hugging the horizon, a dark red Moon greeted early morning skygazers in eastern Atlantic regions on December 21, as the total phase of 2010's Solstice Lunar Eclipse began near moonset. This well composed image of the geocentric celestial event is a composite of multiple exposures following the progression of the eclipse from Tenerife, Canary Islands. Initially reflecting brightly on a sea of clouds and the ocean's surface itself, the Moon sinks deeper into eclipse as it moves from left to right across the sky. Opposite the Sun, the Moon was immersed in the darkest part of Earth's shadow as it approached the western horizon, just before sunrise came to Tenerife.

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Still Life with NGC 2170
Image Credit & Copyright: Adam Block, Mt. Lemmon SkyCenter, U. Arizona

Explanation: In this beautiful celestial still life composed with a cosmic brush, dusty nebula NGC 2170 shines at the upper left. Reflecting the light of nearby hot stars, NGC 2170 is joined by other bluish reflection nebulae, a compact red emission region, and streamers of obscuring dust against a backdrop of stars. Like the common household items still life painters often choose for their subjects, the clouds of gas, dust, and hot stars pictured here are also commonly found in this setting - a massive, star-forming molecular cloud in the constellation Monoceros. The giant molecular cloud, Mon R2, is impressively close, estimated to be only 2,400 light-years or so away. At that distance, this canvas would be about 15 light-years across.

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Analemma 2010
Image Credit & Copyright: Tamas Ladanyi (TWAN)

Explanation: Looking back on the year, have you wondered where the Sun was in the sky each day during 2010 at exacty 9am UT? Of course you have. Search no further for the answer! It was somewhere along this celestial figure 8 curve known as an analemma. Recorded from a residential backyard in the small town of Veszprem, Hungary, this composite analemma image consists of 36 separate exposures of the Sun made at 9:00 UT, spaced throughout the year, plus a background image made without a solar filter. The background image was taken on the sunny afternoon of October 9 (13:45 UT). On the left is the photographer's shadow. The positions of the Sun at the 2010 solstice dates are at the upper (June 21) and lower (December 21) extremes of the analemma curve. On the equinox dates (March 20, September 23) the Sun was along the curve half way between the solstices. The tilt of planet Earth's axis and the variation in speed as it moves around its elliptical orbit combine to produce the graceful analemma curve.

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Fireworks Galaxy NGC 6946
Image Credit & Copyright: Adam Block, Mt. Lemmon SkyCenter, U. Arizona

Explanation: Celebrate the New Year with the Fireworks Galaxy! Also known as NGC 6946, the big, beautiful spiral galaxy is located just 10 million light-years away, behind a veil of foreground dust and stars in the high and far-off constellation of Cepheus. From our vantage point in the Milky Way Galaxy, we see NGC 6946 face-on. In this colorful cosmic portrait, the galaxy's colors change from the yellowish light of old stars in the core to young blue star clusters and reddish star forming regions along the loose, fragmented spiral arms. NGC 6946 is bright in infrared light and rich in gas and dust, exhibiting a furious rate of star formation. Nearly 40,000 light-years across, the nearby spiral is fittingly referred to as the Fireworks Galaxy. Over the last 100 years, at least nine supernovae, the death explosions of massive stars, were discovered in NGC 6946. By comparison, the average rate for supernovae in the Milky Way is about 1 per century.

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Looking Back at an Eclipsed Earth
Credit: Mir 27 Crew; Copyright: CNES

Explanation: Here is what the Earth looks like during a solar eclipse. The shadow of the Moon can be seen darkening part of Earth. This shadow moved across the Earth at nearly 2000 kilometers per hour. Only observers near the center of the dark circle see a total solar eclipse - others see a partial eclipse where only part of the Sun appears blocked by the Moon. This spectacular picture of the 1999 August 11 solar eclipse was one of the last ever taken from the Mir space station. The two bright spots that appear on the upper left are thought to be Jupiter and Saturn. Mir was deorbited in a controlled re-entry in 2001.

Looking Back at an Eclipsed Earth
Credit: Mir 27 Crew; Copyright: CNES

Explanation: Here is what the Earth looks like during a solar eclipse. The shadow of the Moon can be seen darkening part of Earth. This shadow moved across the Earth at nearly 2000 kilometers per hour. Only observers near the center of the dark circle see a total solar eclipse - others see a partial eclipse where only part of the Sun appears blocked by the Moon. This spectacular picture of the 1999 August 11 solar eclipse was one of the last ever taken from the Mir space station. The two bright spots that appear on the upper left are thought to be Jupiter and Saturn. Mir was deorbited in a controlled re-entry in 2001.

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