Found Images: 2015 September

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Cassiopeia A
http://www.capella-observatory.com/Imag ... s/CasA.htm
Copyright: Makis Palaiologou, Johannes Schedler, Josef Pöpsel and Stefan Binnewies

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NS 2
http://www.deeplook.astronomie.at/ns2_basis.htm
Copyright: Markus Blauensteiner

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LBN 331
http://afesan.es/Deepspace/slides/LBN%2 ... us%29.html
Copyright: Antonio Sánchez

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Omega Centauri (NGC 5139)
http://www.glitteringlights.com/Images/ ... 7SjVj9d/X3
Copyright: Marco Lorenzi

Click to view full size image

[bystander]

Hubble Shears a "Woolly" Galaxy
ESA Hubble Picture of the Week | 2015 Sep 21

[img3="Credit: ESA/Hubble, NASA, & S. Smartt (Queen's Univ Belfast)
Acknowledgement: Robert Gendler "]http://cdn.spacetelescope.org/archives/ ... w1538a.jpg[/img3][hr][/hr]

This new image of the spiral galaxy NGC 3521 from the NASA/ESA Hubble Space Telescope is not out of focus. Instead, the galaxy itself has a soft, woolly appearance as it a member of a class of galaxies known as flocculent spirals.

Like other flocculent galaxies, NGC 3521 lacks the clearly defined, arcing structure to its spiral arms that shows up in galaxies such as Messier 101, which are called grand design spirals. In flocculent spirals, fluffy patches of stars and dust show up here and there throughout their discs. Sometimes the tufts of stars are arranged in a generally spiralling form, as with NGC 3521, but illuminated star-filled regions can also appear as short or discontinuous spiral arms.

About 30 percent of galaxies share NGC 3521's patchiness, while approximately 10 percent have their star-forming regions wound into grand design spirals.

NGC 3521 is located almost 40 million light-years away in the constellation of Leo (The Lion). The British astronomer William Herschel discovered the object in 1784. Through backyard telescopes, NGC 3521 can have a glowing, rounded appearance, giving rise to its nickname, the Bubble Galaxy.

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Abell 36
http://astrodonimaging.com/gallery/abel ... -in-virgo/
Copyright: Don Goldman

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Abell 370
http://www.chart32.de/index.php/component/k2/item/124
Copyright: CHART32
Processing: Johannes Schedler

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[bystander]

A Cosmic Rose with Many Names
ESO Photo Release | 2015 Sep 23

[img3="The Star Formation Region Messier 17 - Credit: ESO"]http://cdn.eso.org/images/screen/eso1537a.jpg[/img3][hr][/hr]

This new image of the rose-coloured star forming region Messier 17 was captured by the Wide Field Imager on the MPG/ESO 2.2-metre telescope at ESO’s La Silla Observatory in Chile. It is one of the sharpest images showing the entire nebula and not only reveals its full size but also retains fine detail throughout the cosmic landscape of gas clouds, dust and newborn stars.

The nebula pictured here may have had more names bestowed upon it over the ages than any other object of its kind. Although officially known as Messier 17, its nicknames include: the Omega Nebula, the Swan Nebula, the Checkmark Nebula, the Horseshoe Nebula and — lest those with more of a more marine bent miss out — the Lobster Nebula.

Messier 17 is located about 5500 light-years from Earth near the plane of the Milky Way and in the constellation of Sagittarius (The Archer). The object spans a big section of the sky — its gas and dust clouds measure about 15 light-years across. This material is fueling the birth of new stars and the wide field of view of the new picture reveals many stars in front of, in, or behind Messier 17.

The nebula appears as a complex red structure with some graduation to pink. Its colouring is a signature of glowing hydrogen gas. The short-lived blue stars that recently formed in Messier 17 emit enough ultraviolet light to heat up surrounding gas to the extent that it begins to glow brightly. In the central region the colours are lighter, and some parts appear white. This white colour is real — it arises as a result of mixing the light from the hottest gas with the starlight reflected by dust.

The gas in the nebula is estimated to have more than 30 000 times the mass of the Sun. Messier 17 also contains an open star cluster of 35 stars, which is known as NGC 6618. The total number of stars in the nebula, however, is much higher — there are almost 800 stars in the centre with even more forming in its outer regions.

Throughout this rosy glow, the nebula shows a web of darker regions of dust that obscure the light. This obscuring material is also glowing and — although these areas are dark in this visible-light image — they look bright when observed using infrared cameras.

The nebula owes its official name to the French comet hunter Charles Messier who included the nebula as the seventeenth object in his famous astronomical catalogue in 1764. But even with a name as bland as Messier 17, this flowery nebula still looks dazzling.

This picture comes from the ESO Cosmic Gems programme.

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Sh2-90
http://www.astrophoton.com/S090.htm
Copyright: Bernhard Hubl

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Veil Nebula Supernova Remnant
Hubble Heritage | STScI | AURA | 2015 Sep 24

Hubble Zooms in on the Veil Nebula

[c]Credit: NASA, ESA, Hubble Heritage (STScI/AURA)[/c][hr][/hr]

NASA's Hubble Space Telescope has unveiled in stunning detail a small section of the expanding remains of a massive star that exploded about 8,000 years ago.

Called the Veil Nebula, the debris is one of the best-known supernova remnants, deriving its name from its delicate, draped filamentary structures. The entire nebula is 110 light-years across, covering six full moons on the sky as seen from Earth, and resides about 2,100 light-years away in the constellation Cygnus, the Swan.

This view is a mosaic of six Hubble pictures of a small area roughly two light-years across, covering only a tiny fraction of the nebula's vast structure.

This close-up look unveils wisps of gas, which are all that remain of what was once a star 20 times more massive than our sun. The fast-moving blast wave from the ancient explosion is plowing into a wall of cool, denser interstellar gas, emitting light. The nebula lies along the edge of a large bubble of low-density gas that was blown into space by the dying star prior to its self-detonation.

The image shows an incredible array of structures and detail from the collision between the blast wave and the gas and dust that make up the cavity wall. The nebula resembles a crumpled bed sheet viewed from the side. The bright regions are where the shock wave is encountering relatively dense material or where the "bed sheet" ripples are viewed edge on.

In this image, red corresponds to the glow of hydrogen, green from sulfur, and blue from oxygen. The bluish features, outlining the cavity wall, appear smooth and arched in comparison to the fluffy green and red structures. The red glow is from cooler gas that was excited by the shock collision at an earlier time and has subsequently diffused into a more chaotic structure. A few thin, crisp-looking, red filaments arise after gas is swept into the shock wave at speeds of nearly 1 million miles an hour, so fast that it could travel from Earth to the moon in 15 minutes. ...

Revisiting the Veil Nebula
ESA Hubble Photo Release | 2015 Sep 24

Hubble Zooms in on Shrapnel from an Exploded Star
NASA | STScI | HubbleSite | 2015 Sep 24

Vibrant Gaseous Ribbons: The Veil Supernova Remnant
Credit: NASA, ESA, and F. Summers, G. Bacon, Z. Levay, and L. Frattare (Viz 3D Team, STScI)

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Double Cluster (NGC 884 and NGC 869)
http://www.karelteuwen.be/photo_page.ph ... 5&album=16
Copyright: Karel Teuwen

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NGC 5466
http://www.photonhunter.at/NGC5466.html
Copyright: Patrick Hochleitner and Robert Pölzl

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Total Lunar Eclipse over ESO Headquarters
ESO Picture of the Week | 2015 Sep 28

[img3="Credit: ESO / Mahdi Zamani"]http://cdn.eso.org/images/screen/potw1539a.jpg[/img3][hr][/hr]

On the morning of Monday 28 September 2015 a spectacular total lunar eclipse was witnessed across Africa, the Americas, Europe and the Middle East. In Germany, it was photographed by Mahdi Zamani above the ESO Headquarters Extension and Technical Building. In this time-lapse sequence the Moon was visible between thin layers of cloud. It appeared bright to the upper-left and faded dramatically as it entered the Earth’s shadow and moved lower in the early morning sky.

A lunar eclipse takes place when the Moon, Earth and Sun are exactly aligned. When the Moon passes through the shadow cast by the Earth, our planet blocks the path of direct sunlight to the lunar surface and a total eclipse occurs. This event can only happen on the night of a full Moon.

This morning's total lunar eclipse took place during a supermoon — a full Moon which occurs at the same time that the Moon is closest to Earth in its elliptical orbit. The combination of the eclipsed Moon being both full and relatively close to the Earth made it look significantly bigger and brighter than usual.

Unlike solar eclipses, the Moon doesn't completely disappear from sight during a total lunar eclipse. Instead it often appears red, giving it the ominous nickname of "blood Moon". The reddish colour is caused by refracted sunlight that has passed through the Earth's atmosphere. Furthermore, most of the blue light is scattered away — the same effect that gives the Sun a red colour at sunset and sunrise.

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A Spiral Galaxy’s Brights and Darks (NGC 613)
ESA Hubble Picture of the Week | 2015 Sep 28

[img3="Credit: ESA/Hubble & NASA and S. Smartt (Queen's University Belfast)"]http://cdn.spacetelescope.org/archives/ ... w1539a.jpg[/img3][hr][/hr]

Ribbons of dust festoon the galaxy NGC 613 in this new image from the NASA/ESA Hubble Space Telescope. NGC 613 is classified as a barred spiral galaxy for the bar-shaped band of stars and dust crossing its intensely glowing centre.

About two thirds of spiral galaxies show a characteristic bar shape like NGC 613 — our own galaxy appears to have one of these bars through its midline as well.

NGC 613 lies 65 million light-years away in the constellation of Sculptor (The Sculptor). It was first noted by the English astronomer William Herschel in 1798 and later by John Louis Emil Dreyer, a Danish–Irish astronomer, who recorded the object in his 1888 New General Catalogue of Nebulae and Clusters of Stars — hence the letters "NGC".

NGC 613's core looks bright and uniformly white in this image as a result of the combined light shining from the high concentration of stars packed into the core, but lurking at the centre of this brilliance lies a dark secret. As with nearly all spiral galaxies, a monstrous black hole resides at the heart of NGC 613. Its mass is estimated at about ten times that of the Milky Way's supermassive black hole and it is consuming stars, gas and dust. As this matter descends into the black hole's maw it radiates away energy and spews out radio waves. However, when looking at the the galaxy in the optical and infrared wavelengths used to take this image, there is no trace of the dark heart. ...

[Ann]

http://spacetelescope.org/images/potw1539a/ wrote:
NGC 613's core looks bright and uniformly white in this image as a result of the combined light shining from the high concentration of stars packed into the core

While I agree that there is little (though not zero) color variation in the core, there is a fascinating kind of brightness variation. I think there appears to be a small bar inside the central ring of star formation in this galaxy. The apparent bar is oriented almost directly along our line of sight.

If so, there is a long bar across the bulge of this galaxy, at the inner ends of which there is a starforming ring, inside which there is small bar.

Inside which there is a black hole.

Fascinating!

Ann

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NGC 2865
http://www.spacetelescope.org/images/potw1515a/
Copyright: ESA/Hubble & NASA
Acknowledgement: Judy Schmidt

Click to view full size image

http://asterisk.apod.com/viewtopic.php?t=32705#p218302
http://asterisk.apod.com/viewtopic.php?t=34606#p242279

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CG 1 and CG 2
http://www.astrostudio.at/1_Deep%20Sky% ... 49c16c6bc9
Copyright: Gerald Rhemann

CG 1 is the larger cometary globule on the left while CG 2 is the smaller one on the right. The background nebulosity belongs to the Gum Nebula.

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B145
http://afesan.es/Deepspace/slides/B-145-final.html
Copyright: Antonio Sánchez

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NGC 6868 and NGC 6870
http://members.pcug.org.au/~stevec/ngc6 ... 2_RC14.htm
Copyright: Steve Crouch