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Tycho's Supernova Remnant
Credit: X-ray: NASA/CXC/SAO; Infrared: NASA/JPL-Caltech; Optical: MPIA, Calar Alto, O. Krause et al.

Explanation: What star created this huge puffball? Pictured above is the best multi-wavelength image yet of Tycho's supernova remnant, the result of a stellar explosion first recorded in  Nov 1572 by the famous astronomer Tycho Brahe. The above image is a composite of an X-ray image taken by the orbiting Chandra X-ray Observatory, an infrared image taken by the orbiting Spitzer Space Telescope, and an optical image taken by the 3.5-meter Calar Alto telescope located in southern Spain. The expanding gas cloud is extremely hot, while slightly different expansion speeds have given the cloud a puffy appearance. Although no one is sure which star created SN 1572, a star dubbed Tycho G, too dim to be easily discerned here, is being studied as the possible progenitor. Finding the progenitor remnant of Tycho's supernova is particularly important because the supernova was recently determined to be of Type Ia. The peak brightness of Type Ia supernovas is thought to be well understood, making them quite valuable in calibrating how our universe dims distant objects.

SN 1572 (Tycho's Supernova, Tycho's Nova), "B Cassiopeiae" (B Cas), or 3C 10 was a supernova of Type Ia[1] in the constellation Cassiopeia, one of about eight supernovae visible to the naked eye in historical records. It burst forth in early November 1572 and was independently discovered by many individuals. [2]

 Historic description from Wikipedia

The appearance of the Milky Way supernova of 1572 was perhaps one of the two or three most important events in the history of astronomy. The "new star" helped to revise ancient models of the heavens and to inaugurate a tremendous revolution in astronomy that began with the realized need to produce better astrometric star catalogues (and thus the need for more precise astronomical observing instruments). The supernova of 1572 is often called "Tycho's supernova", because of the extensive work that Tycho Brahe (1573, 1602, 1610)[clarification needed] did in both observing the new star and in analyzing his own observations and those of many other observers. But Tycho was not even close to being the first to observe the 1572 supernova, although he was apparently the most accurate observer of the object (though not by much over some of his European colleagues like Wolfgang Schuler, Thomas Digges, John Dee and Francesco Maurolico).

In England, Queen Elizabeth called to her the mathematician and astrologer Thomas Allen, "to have his advice about the new Star that appeared in the Cassiopeia to which he gave his Judgement very learnedly," the antiquary John Aubrey recorded in his memoranda a century later.[3]

The more reliable contemporary reports state that the new star itself burst forth sometime between 1572 November 2 and 6, when it rivalled Venus in brightness. This corresponds to an absolute magnitude of -15.8, nearly twenty times as bright as a full moon. The supernova remained visible to the naked eye into 1574, gradually fading until it disappeared from view.

  Supernova remnant

  Radiological detection

The search for a supernova remnant was negative until 1952, when Hanbury Brown and Hazard reported a radio detection at 158.5 MHz.[4] This was confirmed at wavelength 1.9 m by Baldwin and Edge (1957),[5] and the remnant was also identified tentatively in the second Cambridge radio-source catalogue as object "2C 34" and identified more firmly as "3C 10" in the third Cambridge list (Edge et al. 1959). There is no dispute that 3C 10 is the remnant of the supernova observed in 1572-1573. Following a review article by Minkowski (1964),[6] the designation 3C 10 appears to be that most commonly used in the literature when referring to the radio remnant of B Cas (though some authors use the tabulated Galactic designation G120.7+2.1 of Green 1984, and many authors commonly refer to it as "Tycho's supernova remnant"—somewhat of a misnomer, as Tycho saw the pointlike supernova, not the expansive radio remnant). Because the radio remnant was reported before the optical supernova-remnant wisps were discovered, the designation 3C 10 is used by some to signify the remnant at all wavelengths.

SN 1572 is associated with the radio source G.120·1+1·4. It has an apparent diameter of 7.4 arc minutes, and is located approximately 7,500 light-years (2.3 kpc) from our Solar system.

  Optical detection

The supernova remnant of B Cas was discovered in the 1960s by scientists with a Palomar Mountain telescope as a very faint nebula. It was later photographed by a telescope on the international ROSAT spacecraft. The supernova has been confirmed as Type Ia,[1] in which a white dwarf star has accreted matter from a companion until it reaches the Chandrasekhar limit and explodes. This type of supernova does not typically create the spectacular nebula more typical of Type II supernovas, such as SN 1054 which created the Crab Nebula. A shell of gas is still expanding from its center at about 9,000 km/s.

   Discovery of the companion star

In October 2004, a letter in Nature reported the discovery of a G2 star, similar in type to our own Sun.[7] It is thought to be the companion star that contributed mass to the white dwarf that ultimately resulted in the supernova. A subsequent study, published in March 2005, revealed further details about this star: labeled Tycho G, it was likely a main sequence star or subgiant prior to the explosion, but had some of its mass stripped away and its outer layers shock-heated from the effects of the supernova. Tycho G's current velocity is perhaps the strongest evidence that it was the companion star to the white dwarf, as it is traveling at a rate of 136 km/s, which is more than forty times faster than the mean velocity of other stars in its stellar neighbourhood.

  Observation of light echo

In September 2008, the Subaru telescope obtained the optical spectrum of Tycho Brahe's supernova near maximum brightness from a scattered-light echo.[8] It has been confirmed that SN 1572 belongs to the majority class of normal SNe Ia.

 See also


  1. ^ a b c Krause, Oliver; et al. (2008). "Tycho Brahe's 1572 supernova as a standard type Ia as revealed by its light-echo spectrum". Nature 456 (7222): 617–619. doi:10.1038/nature07608. 
  2. ^ Blast From The Past: Astronomers Resurrect 16th-Century Supernova ScienceDaily (Dec. 4, 2008)
  3. ^ Oliver Lawson Dick, ed. Aubrey's Brief Lives. Edited from the Original Manuscripts, 1949, s.v. "Thomas Allen" p. 5.
  4. ^ Hanbury-Brown, R.; Hazard, C. (1952). "Radio-Frequency Radiation from Tycho Brahe's Supernova (A.D. 1572)". Nature 170 (4322): 364–365. doi:10.1038/170364a0. 
  5. ^ Baldwin, J. E.; Edge, D. O. (1957). "Radio emission from the remnants of the supernovae of 1572 and 1604". The Observatory 77: 139–143. Bibcode1957Obs....77..139B. 
  6. ^ Minkowski, R. (1964). "Supernovae and Supernova Remnants". Annual Review of Astronomy and Astrophysics 2: 247–266. doi:10.1146/annurev.aa.02.090164.001335. 
  7. ^ Ruiz-Lapuente, Pilar; et al. (2004). "The binary progenitor of Tycho Brahe's 1572 supernova". Nature 431 (7012): 1069–1072. doi:10.1038/nature03006. 
  8. ^ "Tycho Brahe's 1572 supernova as a standard type Ia explosion revealed from its light echo spectrum". October 28, 2008. 

 External links



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IC 5146: The Cocoon Nebula
Credit & Copyright: Neil Fleming, David Plesko

Explanation: Inside the Cocoon Nebula is a newly developing cluster of stars. Cataloged as IC 5146, the beautiful nebula is nearly 15 light-years wide, located some 4,000 light years away toward the northern constellation Cygnus. Like other star forming regions, it stands out in red, glowing, hydrogen gas excited by young, hot stars and blue, dust-reflected starlight at the edge of an otherwise invisible molecular cloud. In fact, the bright star near the center of this nebula is likely only a few hundred thousand years old, powering the nebular glow as it clears out a cavity in the molecular cloud's star forming dust and gas. This exceptionally deep color view of the Cocoon Nebula traces tantalizing features within and surrounding the dusty stellar nursery.


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Orion Nebula: The Hubble View
Credit: NASA, ESA, M. Robberto (STScI/ESA) et al.

Explanation: Few cosmic vistas excite the imagination like the Orion Nebula. Also known as M42, the nebula's glowing gas surrounds hot young stars at the edge of an immense interstellar molecular cloud only 1,500 light-years away. The Orion Nebula offers one of the best opportunities to study how stars are born partly because it is the nearest large star-forming region, but also because the nebula's energetic stars have blown away obscuring gas and dust clouds that would otherwise block our view - providing an intimate look at a range of ongoing stages of starbirth and evolution. This detailed image of the Orion Nebula is the sharpest ever, constructed using data from the Hubble Space Telescope's Advanced Camera for Surveys  (which no longer functions) and the European Southern Observatory's La Silla 2.2 meter telescope. The mosaic contains a billion pixels at full resolution and reveals about 3,000 stars.


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Inside the Eagle Nebula
Credit & Copyright: T. A. Rector & B. A. Wolpa, NOAO, AURA

Explanation: From afar, the whole thing looks like an Eagle. A closer look at the Eagle Nebula, however, shows the bright region is actually a window into the center of a larger dark shell of dust. Through this window, a brightly-lit workshop appears where a whole open cluster of stars is being formed. In this cavity tall pillars and round globules of dark dust and cold molecular gas remain where stars are still forming. Already visible are several young bright blue stars whose light and winds are burning away and pushing back the remaining filaments and walls of gas and dust. The Eagle emission nebula, tagged M16, lies about 6500 light years away, spans about 20 light-years, and is visible with binoculars toward the constellation of the Serpent (Serpens). This picture combines three specific emitted colors and was taken with the 0.9-meter telescope on Kitt Peak, Arizona, USA.


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NGC 1579: Trifid of the North
Credit & Copyright: Don Goldman

Explanation: Colorful NGC 1579 resembles the better known Trifid Nebula, but lies much farther north in planet Earth's sky, in the heroic constellation Perseus. About 2,100 light-years away and 3 light-years across, NGC 1579 is, like the Trifid, a study in contrasting blue and red colors, with dark dust lanes prominent in the nebula's central regions. In both regions, dust reflects starlight to produce beautiful blue reflection nebulae. But unlike the Trifid, in NGC 1579 the reddish glow is not emission from clouds of glowing hydrogen gas excited by ultraviolet light from a nearby hot star. Instead, the dust in NGC 1579 drastically diminishes, reddens, and scatters the light from an embedded, extremely young, massive star, itself is strong emitter of the characteristic red hydrogen alpha light.



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AE Aurigae and the Flaming Star Nebula
Credit & Copyright: Jorge Garcia

Explanation: Is star AE Aurigae on fire? No. Even though AE Aurigae is named the flaming star, the surrounding nebula IC 405 is named the Flaming Star Nebula, and the region appears to harbor red smoke, there is no fire. Fire, typically defined as the rapid molecular acquisition of oxygen, happens only when sufficient oxygen is present and is not important in such high-energy, low-oxygen environments such as stars. The material that appears as smoke is mostly interstellar hydrogen, but does contain smoke-like dark filaments of carbon-rich dust grains. The bright star AE Aurigae, visible near the nebula center, is so hot it is blue, emitting light so energetic it knocks electrons away from surrounding gas. When a proton recaptures an electron, red light is frequently emitted, as seen in the surrounding emission nebula. Pictured above, the Flaming Star nebula lies about 1,500 light years distant, spans about 5 light years, and is visible with a small telescope toward the constellation of the Charioteer (Auriga).


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IC 1805: The Heart Nebula
Credit & Copyright: Daniel Marquardt

Explanation: Sprawling across almost 200 light-years, emission nebula IC 1805 is a mix of glowing interstellar gas and dark dust clouds. Derived from its Valentine's-Day-approved shape, its nickname is the Heart Nebula. About 7,500 light-years away in the Perseus spiral arm of our galaxy, stars were born in IC 1805. In fact, near the cosmic heart's center are the massive hot stars of a newborn star cluster also known as Melotte 15, about 1.5 million years young. A little ironically, the Heart Nebula is located in the constellation Cassiopeia. From Greek mythology, the northern constellation is named for a vain and boastful queen. This deep view of the region around the Heart Nebula, cropped from a larger mosaic, spans about 2.5 degrees on the sky or about 5 times the diameter of the Full Moon.


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Globular Cluster NGC 2419  (Closeup Photo Below)
Credit & Copyright: Richard Hammar

Explanation: Of three objects prominent in this thoughtful telescopic image, a view toward the stealthy constellation Lynx, two (the spiky ones) are nearby stars. The third is the remote globular star cluster NGC 2419, at distance of nearly 300,000 light-years. NGC 2419 is sometimes called "The Intergalactic Wanderer," an appropriate title considering that the distance to the Milky Way's satellite galaxy, the Large Magellanic Cloud, is only about 160,000 light-years. Roughly similar to other large globular star clusters like Omega Centauri, NGC 2419 is itself intrinsically bright, but appears faint because it is so far away. NGC 2419 may really have an extragalactic origin as, for example, the remains of a small galaxy captured and disrupted by the Milky Way. But its extreme distance makes it difficult to study and compare its properties with other globular clusters that roam the halo of our Milky Way galaxy.




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Planetary Nebula NGC 2818
Credit: NASA, ESA, Hubble Heritage Team (STScI / AURA)

Explanation: NGC 2818 is a beautiful planetary nebula, the gaseous shroud of a dying sun-like star. It could well offer a glimpse of the future that awaits our own Sun after spending another 5 billion years or so steadily using up hydrogen at its core, and then finally helium, as fuel for nuclear fusion. Curiously, NGC 2818 seems to lie within a sparse open star cluster, NGC 2818A, that is some 10,000 light-years distant toward the southern constellation Pyxis (Compass). Since open star clusters disperse after only a few hundred million years, this one must be exceptionally old to have one of its member stars evolve to the planetary nebula stage. At the distance of the star cluster, planetary nebula NGC 2818 would be about 4 light-years across. The Hubble image is a composite of exposures through narrow-band filters, presenting emission from nitrogen, hydrogen, and oxygen atoms in the nebula as red, green, and blue hues.


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The Galactic Core in Infrared
Credit: Hubble: NASA, ESA, & D. Q. Wang (U. Mass, Amherst); Spitzer: NASA, JPL, & S. Stolovy (SSC/Caltech)

Explanation: What's happening at the center of our Milky Way Galaxy? To help find out, the orbiting Hubble and Spitzer space telescopes have combined their efforts to survey the region in unprecedented detail in infrared light. Infrared light is particularly useful for probing the Milky Way's center because visible light is more greatly obscured by dust. The above image encompasses over 2,000 images from the Hubble Space Telescope's NICMOS taken last year. The image spans 300 by 115 light years with such high resolution that structures only 20 times the size of our own Solar System are discernable. Clouds of glowing gas and dark dust as well as three large star clusters are visible. Magnetic fields may be channeling plasma along the upper left near the Arches Cluster, while energetic stellar winds are carving pillars near the Quintuplet Cluster on the lower left. The massive Central Cluster of stars surrounding Sagittarius A* is visible on the lower right. Why several central, bright, massive stars appear to be unassociated with these star clusters is not yet understood.


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NGC 2736: The Pencil Nebula
Credit & Copyright: Ken Crawford (Rancho Del Sol Observatory)

Explanation: This shock wave plows through space at over 500,000 kilometers per hour. Moving right to left in the beautifully detailed color composite, the thin, braided filaments are actually long ripples in a sheet of glowing gas seen almost edge on. Cataloged as NGC 2736, its narrow appearance suggests its popular name, the Pencil Nebula. About 5 light-years long and a mere 800 light-years away, the Pencil Nebula is only a small part of the Vela supernova remnant. The Vela remnant itself is around 100 light-years in diameter, the expanding debris cloud of a star that was seen to explode about 11,000 years ago. Initially, the shock wave was moving at millions of kilometers per hour but has slowed considerably, sweeping up surrounding interstellar gas.


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Collinder 399: The Coat Hanger
Credit & Copyright: Processing - Noel Carboni, Imaging - Greg Parker, New Forest Observatory

Explanation: Is this coat hanger a star cluster or an asterism? This cosmic hang-up has been debated over much of last century, as astronomers wondered whether this binocular-visible object is really a physically associated open cluster or a chance projection. Chance star projections are known as asterisms, an example of which is the popular Big Dipper. Recent precise measurements from different vantage points in the Earth's orbit around the Sun have uncovered discrepant angular shifts indicating that the Coat Hanger is better described as an asterism. Known more formally as Collinder 399, this bright stellar grouping is wider than the full moon and lies in the constellation of the Fox (Vulpecula). On the far right of the image is the open cluster of stars NGC 6802.


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Venus in the Moon
Credit & Copyright: Johannes Schedler (Panther Observatory)
Inset: Vincent Jacques

Explanation: On December 1, bright planets Venus and Jupiter gathered near the young crescent Moon, an inspiring celestial scene in early evening skies around the world. But from some locations the Moon actually passed in front of Venus, interrupting the tight grouping with a lunar occultation. Captured from Wildon, Austria, this twilight view shows the silvery evening star about five minutes before it slipped behind the dark lunar limb and vanished from sight for more than hour. The image is a combination of long and short exposures showing details of the lunar surface illuminated by both faint earthshineskies over Breil-sur-Roya in southeastern France, a dazzling Venus has reappeared below the bright lunar crescent. Of course, Jupiter, at the upper right about 3 degrees from Venus and Moon, is sporting moons of its own seen as tiny pinpricks of light on either side of the bright planet Ganymede above left, Callisto lower right. The larger picture was at twilight. In the inset, recorded later  the sky had  darkened.

AURORA WATCH: On Nov 30 in far-northern Nunavik, Quebec, the clouds parted to reveal a green and purple ribbon of light winding among the stars. Sylvain Serre grabbed his Canon 30D and snapped this picture:
Photo details: Canon EOS 30D, 10mm, f/3.5, ISO 800, 20 sec

"November has been a good month for auroras," says Serre. "We've had five clear nights and I saw the Northern Lights every time." Serre's home in far-northern Quebec lies under Earth's auroral oval, a glowing ring around the North Pole where auroras are almost constantly active. Last night's display was encouraged by a crack in Earth's magnetosphere briefly opening and allowing solar wind to pour in. It was a minor display by the standards of Nunavik--"not very beautiful," deadpans Serre, "but we enjoyed it anyway."

A better show is in the offing. A solar wind stream is heading for Earth and it could spark geomagnetic storms when it arrives on Dec. 3rd or 4th. High-latitude sky watchers should be alert for auroras.

Nov. 2008 Aurora Gallery
[Previous Novembers: 2007, 2006, 2004, 2003, 2001, 2000]

From for 2008 Dec 1


Massive Stars Resolved in the Carina Nebula

Credit: NASA, ESA, and J. Maíz Apellániz (Instituto de Astrofísica de Andalucía, Spain)

Explanation: How massive can stars be? Big, hefty stars live short violent lives that can profoundly affect their environments. Isolating a massive star can be problematic, however, since what seems to be a single bright star might actually turn out to be several stars close together. Such was the case for two of the brightest objects visible in the open star cluster Trumpler 16, located in the southern Carina Nebula. Upon close inspection by the Hubble Space Telescope, WR 25, the brightest object in the above image, was confirmed to consist of at least two separate stars. Additionally, Tr16 -244, just to the upper right of WR 25, was resolved for the first time to be at least three individual stars. Even so, the brightest star in WR 25Winds from these stars are likely significant contributers to the large bubble that the star cluster sits in. The Carina Nebula, home to unusually shaped dust clouds and the famous variable star Eta Carina, lies about 7,500 light years away toward the constellation of Ship's KeelCarina). appears to be about 50 times the mass of our Sun, making it one of the more massive stars known.

 Above From The Astronomy Picture of the Day for 2008 Nov 30 at:



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The Dumbbells
Credit & Copyright: Daniel López, IAC

Explanation: These two nebulae are cataloged as M27 (left) and M76, popularly known as The Dumbbell and the Little Dumbbell. Not intended to indicate substandard mental prowess, their popular names refer to their similar, dumbbell or hourglass shapes. Both are planetary nebulae, gaseous shrouds cast off by dying sunlike stars, and are similar in physical size, at a light-year or so across. In each panel, the images were made at the same scale, so the apparent size difference is mostly because one is closer. Distance estimates suggest 1,200 light-years for the Dumbbell compared to 3,000 light-years or more for the Little Dumbell. These deep, narrow-band, false-color images show some remarkably complex structures in M27 and M76, highlighting emission from hydrogen, nitrogen, and oxygen atoms within the cosmic clouds.


ASTRONOMY PICTURE OF THE DAY for 2008 December 14 

Zodiacal Light Over New Mexico 

Explanation: An unusual triangle of light is visible this time of year just before dawn.  Once considered a false dawn, this triangle of light is actually  Zodiacal Light,  predominantly in the same plane as the planets: the, light reflected from interplanetary dust particles . The triangle is clearly visible in the image above  taken from New Mexico, USA,  in October. Curvature by the wide-angle lens makes foreground trees and a nearby water tower appear less vertical than they really are. Zodiacal dust orbits the Sun predominantly in the same plane as the planets: the ecliptic. Zodiacal light is so bright this time of year because the dust band is oriented nearly vertical at sunrise, so that the thick air near the horizon does not block out relatively bright reflecting dust. Zodiacal light is also bright for people in Earth's northern hemisphere in March and April just after sunset.

ASTRONOMY PICTURE OF THE DAY for 2008 December 11 

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At the Center of the Milky Way Galaxy
Credit: ESO, Stefan Gillessen (MPE), F. Eisenhauer, S. Trippe, T. Alexander, R. Genzel, F. Martins, T. Ott

Explanation: At the center of our Milky Way Galaxy lies a supermassive black hole. Once a controversial claim, this conclusion is now solidly based on 16 years of observations that map the orbits of 28 stars very near the galactic center. Using European Southern Observatory telescopes and sophisticated near infrared cameras, astronomers patiently measured the positions of the stars over time, following one star, designated S2, through a complete orbit as it came within about 1 light-day of the center of the Milky Way. Their results convincingly show that S2 is moving under the influence of the enormous gravity of a compact, unseen object -- a black hole with 4 million times the mass of the Sun. Their ability to track stars so close to the galactic center accurately measures the black hole's mass and also determines the distance to the center to be 27,000 light-years. This deep, near-infrared image shows the crowded inner 3 light-years of the central Milky Way. Spectacular time-lapse animations of the stars orbiting within light-days of the galactic center can be found here.



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Restored: First Image of the Earth from the Moon

Explanation: Pictured above is the first image ever taken of the Earth from the Moon. The image was taken in 1966 by Lunar Orbiter 1 and heralded by then-journalists as the Image of the Century. It was taken about two years before the Apollo 8 crew snapped its more famous color cousin. Recently, modern technology has allowed the recovery of higher resolution images from old data sources such as Lunar Orbiter tapes than every before. Specifically, the above image recovery was led by Nancy Evans as part of the Lunar Orbiter Image Recovery Project. Images like that above carry more than aesthetic value -- comparison to recent high definition images of the Moon enables investigations into how the Moon has been changing.


Featured Image - The Launch of STS-126 on 2008 Nov 14 at 7:55 PM EST

          NOTE The Moon Almost Two Days Past Full to the Upper Right of the Blazing Shuttle

Endeavour Lifts Off

Blazing light surroundsSpace Shuttle Endeavour, eclipsing the light from the nearby Waning Gibbous Moon, as it roars toward space from Launch Pad 39A at NASA's Kennedy Space Center. Liftoff was on time at 7:55 p.m. EST.

Image credit: NASA/Troy Cryder
Nov. 14, 2008

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                                      THE ASTRONOMY PICTURE OF THE DAY FOR  2008 November 10 

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Our Galaxy's Central Molecular Zone
Credit: A. Ginsburg (U. Colorado - Boulder) et al., BGPS Team, GLIMPSE II Team

Explanation: The central region of our Milky Way Galaxy is a mysterious and complex place. Pictured here in radio and infrared light, the galaxy's central square degree is highlighted in fine detail. The region is known as the Central Molecular Zone. While much of the extended emission is due to dense gas laced with molecules, also seen are emission nebulas lit up by massive young stars, glowing supernova remnants, and the curving Galactic Center Radio Arc in purple. The identity and root cause for many other features remains unknown. Besides a massive black hole named Sgr A*, the Galactic Center houses the galaxy's most active star forming region. This image is not just interesting scientifically. It's esthetic beauty won first prize this year in the AUI/NRAO Image Contest.

                                    THE ASTRONOMY PICTURE OF THE DAY FOR 2008 November 3 

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A Spectacular Rayed Crater on Mercury

Explanation: Why does Mercury have so many rayed craters? No one is sure. The robotic MESSENGER spacecraft that is taking unprecedented images as it swoops past the innermost planet has provided dramatic confirmation that Mercury has more rayed craters than Earth's Moon. Pictured above, a particularly spectacular rayed crater spanning approximately 80 kilometers was imaged by MESSENGER during last month's flyby from about 20,000 kilometers up. The rays prevalence is a mystery because space weathering effects such as dust accumulation and solar wind attenuation should be greater on Mercury than on the Moon. Hypothesized solutions currently include the optical properties of Mercurian dust, and that Mercury's high mass and proximity to the Sun cause more violent impacts, thus typically raising more light material. MESSENGER will buzz past Mercury again  on the third of three flybys next year on September 29 before entering orbit in  March 2011.

                                    THE  ASTRONOMY PICTURE OF THE DAY  for  2008 November 1 

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A Spectre in the Eastern Veil
Credit & Copyright: Paul Mortfield, Stefano Cancelli

Explanation: Menacing flying forms and garish colors are a mark of the Halloween season. They also stand out in this cosmic close-up of the eastern Veil Nebula. The Veil Nebula itself is a large supernova remnant, the expanding debris cloud from the death explosion of a massive star. While the Veil is roughly circular in shape covering nearly 3 degrees on the sky in the constellation Cygnus, this portion of the eastern Veil spans only 1/2 degree, about the apparent size of the Moon. That translates to 12 light-years at the Veil's estimated distance of 1,400 light-years from planet Earth. In this composite of image data recorded through narrow band filters, emission from hydrogen atoms in the remnant is shown in red with strong emission from oxygen atoms in greenish hues. In the western part of the Veil lies another seasonal apparition, the Witch's Broom. See Below:

                                                           THE ASTRONOMY PICTURE OF THE DAY for 2007 January 1 

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NGC 6960: The Witch's Broom Nebula
Credit & Copyright: T. A. Rector (U. Alaska), WIYN, NOAO, AURA, NSF

Explanation: Ten thousand years ago, before the dawn of recorded human history, a new light must suddenly have appeared in the night sky and faded after a few weeks. Today we know this light was an exploding star and record the colorful expanding cloud as the Veil Nebula. Pictured above is the west end of the Veil Nebula known technically as NGC 6960 but less formally as the Witch's Broom Nebula. The rampaging gas gains its colors by impacting and exciting existing nearby gas. The supernova remnant lies about 1400 light-years away towards the constellation of Cygnus. This Witch's Broom actually spans over three times the angular size of the full Moon. The bright star 52 Cygnus is visible with the unaided eye from a dark location but unrelated to the ancient supernova.

                   THE ASTRONOMY PICTURE OF THE DAY for 2008 October 26

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Massive Stars in Open Cluster Pismis 24
Credit: NASA, ESA and J. M. Apellániz (IAA, Spain)

Explanation: How massive can a normal star be? Estimates made from distance, brightness and standard solar models had given one star in the open cluster Pismis 24 over 200 times the mass of our Sun, making it a record holder. This star is the brightest object located just above the gas front in the above image. Close inspection of images taken recently with the Hubble Space Telescope, however, have shown that Pismis 24-1 derives its brilliant luminosity not from a single star but from three at least. Component stars would still remain near 100 solar masses, making them among the more massive stars currently on record. Toward the bottom of the image, stars are still forming in the associated emission nebula NGC 6357, including several that appear to be breaking out and illuminating a spectacular cocoon.

                                 THE ASTRONOMY PICTURE OF THE DAY FOR 2008 October 22
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Beautiful Spiral NGC 7331
Credit & Copyright: Vicent Peris (OAUV / PTeam), Gilles Bergond, Calar Alto Observatory.

Explanation: A favorite target for astronomers, big, beautiful spiral galaxy NGC 7331 is one of the brighter galaxies not found in Charles Messier's famous 18th century catalog. About 50 million light-years distant in the northern constellation Pegasus and similar in size to our own Milky Way Galaxy, NGC 7331 is often imaged as the foreground of a visual grouping that includes an intriguing assortment of background galaxies some ten times farther away. This striking image of the well-studied island universe and environs was produced using data from the Calar Alto Observatory in southern Spain. Perhaps the deepest view of the region yet, the image data were processed to reveal sharp details of all sizes in both bright and faint areas. A color balance was chosen so that white would be the result of averaging colors over the entire galaxy. The result shows off a wealth of remarkable features in NGC 7331 and its surroundings.

                                                 NGC STANDS FOR NEW GENERAL CATALOGUE

                             MORE Astronomy Pictures of the Day



                          PHOTO TAKEN BY SAULI KOSKI  IN FINLAND AND POSTED ON   for October 11


                                Bolide passes the Hyades Cluster in Taurus at top and  then  at its brightest to the upper left of Orion 

                                                                                                          2008 October 11
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Bright Bolide
Credit & Copyright: Howard Edin (Oklahoma City Astronomy Club)

Explanation: On September 30, a spectacular bolide or fireball meteor surprised a group of amateur astronomers enjoying dark night skies over the Oklahoma panhandle's Black Mesa State Park in the Midwestern US. Flashing past familiar constellations Taurus (top) and Orion, the extremely bright meteor was captured by a hillside camera overlooking the 2008 Okie-Tex Star Party. Astronomy enthusiast Howard Edin reports that he was looking in the opposite direction at the time, but saw the whole observing field light up and at first thought someone had turned on their car headlights. So far the sighting of a such a bright bolide meteor, produced as a space rock is vaporized hurtling through Earth's atmosphere, really is a matter of luck. But that could change. Earlier this week the discovery and follow-up tracking of tiny asteroid 2008 TC3 allowed astronomers to predict the time and location of its impact with the atmosphere. While no ground-based sightings of the fireball seem to have been reported, this first ever impact prediction was confirmed by at least some detections of an air burst and bright flash on October 7th over northern Sudan.

                                                                                                             2008 October 18 

Explanation: Cosmic pillars of cold molecular gas and clouds of dark dust lie within Sharpless 171, a star-forming region some 3,000 light-years away in the royal constellation Cepheus. This tantalizing false-color skyscape spans about 20 light-years across the nebula's bright central region. It also highlights the pervasive glow of emission from atomic gas using narrowband filters and a color palette made popular in Hubble Space Telescope images. Powering the nebular glow are the young, hot stars of a newly formed cluster, Berkeley 59. Of course, this star-forming region is entry number 171 in the famous 1959 catalog of emission nebulae compiled by astronomer Stewart Sharpless. 

s171_asaf3_hst_v1_33.jpg (240544 bytes)

                            Sharpless 171 and Berkeley 59, HII region and open cluster in Cepheus

    Technical Details:

    Object: S171 in Cepheus
    Observing Site: Azor Observatory, Las Rozas, Madrid, Spain. 18.84 mag arcsec-2
    Date: Data acquired on July 13-14 (Ha), August 30, 31 (OIII) and September 3 (SII). 2008 
    Camera: SBIG STL-11000M @ -15ºC
    Telescope: ASA N10 Astrograph @ f/3.6, Astrophysics AP1200 mount
    Filters: Astrodon 6nm H alpha, OIII and SII
    Exposure: 1140 minutes (19 hours, 38x30 min subs)
    Processing Software: Maxim DL, Photoshop
    Comments: CCD Commander used for unattended data acquisition. Shown  at 33%

                                                                   from the    ASTRONOMY PICTURE OF THE DAY

                                                                                                                  2008 OCTOBER 18

                                                                                                                         Sharpless 171

Credit & Copyright: Antonio Fernandez


                                                    ASTRONOMY PICTURE OF THE DAY for  2008 OCTOBER 16 

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48 Years of Space Flight
Credit & Copyright: Ralf Vandebergh

Explanation: This year, NASA celebrated its 50th anniversary. Inspired to make his own contribution, astronomer Ralf Vandebergh set out to record images of some historic spacecraft in Earth orbit -- captured with his own modest equipment and a hand-guided, 10-inch, Newtonian reflecting telescope. One result is this intriguing composite effectively spanning 48 years of space flight! From a 1960 launch, on the left is the TIROS 2 satellite, one of the first successful weather satellites. While this TIROS (Television InfraRed Observation System) satellite stopped functioning in 1961, Vandeberg notes that if we could visit it now, we would still find video cameras and magnetic tape recorders. On the right, of course, is the ISS (International Space Station) including its recent addition, the Progress M-65 cargo vehicle, launched to the ISS just last month.

                                                                                                                   2008 October 17
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An Extraordinary Voyage
Credit: Jesse Carpenter, Bill Moede, Peter Jenniskens (NASA Ames Research Center)

Explanation: Nineteenth century science fiction author Jules Verne wrote visionary works about Extraordinary Voyages including tales of space flight and the story of a journey From the Earth to the Moon. Fittingly, the European Space Agency's newly developed Automated Transfer Vehicle (ATV), a robotic spacecraft intended to deliver cargo to the International Space Station (ISS) was named in his honor and successfully docked with the ISS earlier this year. When the Jules Verne ATV was undocked and deorbited last month, its safely controlled reentry over the Pacific Ocean was followed by astronomers in order to make detailed comparisons of the actual event with computer models of spacecraft reentry and breakup in the atmosphere. This dramatic image of the fragmenting, 13-ton spacecraft is a high definition video frame recorded from NASA's DC-8 Airborne Laboratory. The observations were part of the joint ESA/NASA Jules Verne Multi-Instrument Aircraft Campaign.


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The Dark Doodad Nebula
Credit & Copyright: Andrey Oreshko

Explanation: What is that strange dark ribbon on the sky? When observing the great globular cluster NGC 4372, observers frequently take note of a strange dark streak nearly three degrees in length running near it. Unnamed, the streak, actually a long molecular cloud, has become known as the Dark Doodad Nebula. (Doodad is slang for a thingy or a whatchamacallit.) Pictured above in a rich and colorful star-field, the Dark Doodad Nebula can be found sweeping across the image center. The globular star cluster NGC 4372 is visible on the image left, while the bright star gamma Musca is seen to the cluster's right. The Dark Doodad Nebula can be found with strong binoculars toward the southern constellation of the Fly (Musca). The above image was compiled by consecutive 45 minutes exposures taken by a small telescope from the La Frontera region in Chile.