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APOD: NGC 6369: The Little Ghost Nebula (2017 Oct 28)
Posted: Sat Oct 28, 2017 4:07 am
by APOD Robot
NGC 6369: The Little Ghost Nebula
Explanation: Wraithlike NGC 6369 is a faint apparition in night skies popularly known as the Little Ghost Nebula. It was discovered by 18th century astronomer
Sir William Herschel as he used a telescope to explore the medicinal
constellation Ophiucus. Herschel historically classified the round and planet-shaped nebula as a Planetary Nebula. But
planetary nebulae in general are not at all related to planets. Instead they are gaseous shrouds created at the end of a sun-like star's life, the dying star's outer layers expanding into space while its core shrinks to become a white dwarf. The transformed
white dwarf star, seen near the center, radiates strongly at ultraviolet wavelengths and powers the expanding nebula's glow. Surprisingly
complex details and structures of NGC 6369 are revealed in
this tantalizing image composed from Hubble Space Telescope data. The nebula's main round structure is about
a light-year across and the glow from ionized oxygen, hydrogen, and nitrogen atoms are colored blue, green, and red respectively. Over 2,000 light-years away, the
Little Ghost Nebula offers a glimpse of the fate of our Sun, which could produce its own planetary nebula about 5 billion years from now.
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Re: APOD: NGC 6369: The Little Ghost Nebula (2017 Oct 28)
Posted: Sat Oct 28, 2017 4:18 am
by Avent
Good job
Re: APOD: NGC 6369: The Little Ghost Nebula (2017 Oct 28)
Posted: Sat Oct 28, 2017 5:19 am
by De58te
The color is simply ghoulish looking. Reminds me of looking into a witch's boiling cauldron. By the way, sure hope there isn't a witch head nebula out there. That image would simply be spell-bounding.
Re: APOD: NGC 6369: The Little Ghost Nebula (2017 Oct 28)
Posted: Sat Oct 28, 2017 7:21 am
by Boomer12k
De58te wrote:The color is simply ghoulish looking. Reminds me of looking into a witch's boiling cauldron. By the way, sure hope there isn't a witch head nebula out there. That image would simply be spell-bounding.
Ummm... hate to be the one to break it to you....BUT....
https://www.nasa.gov/multimedia/imagega ... _1209.html
Have a Happy....
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Re: APOD: NGC 6369: The Little Ghost Nebula (2017 Oct 28)
Posted: Sat Oct 28, 2017 7:28 am
by Boomer12k
Interesting one... also looks like there was an "event", before the "big push"....
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"Wraithlike NGC 6369"
Posted: Sat Oct 28, 2017 12:48 pm
by neufer
http://heritage.stsci.edu/2002/25/caption.html wrote:
<<The doughnut-shaped blue-green ring represents light from ionized oxygen atoms that have lost two electrons (blue) and from hydrogen atoms that have lost their single electrons (green). Red marks emission from nitrogen atoms that have lost only one electron.>>
https://en.wikipedia.org/wiki/Nazg%C3%BBl wrote:
<<The Nazgûl (from Black Speech nazg, "ring", and gûl, "wraith, spirit", possibly related to gul, "sorcery" or a wordplay on "ghoul" ), also called Ringwraiths, Ring-wraiths, Black Riders, Dark Riders, the Nine Riders, or simply the Nine, are fictional characters in J. R. R. Tolkien's Middle-earth legendarium. They were nine men who succumbed to Sauron's power and attained near-immortality as wraiths, servants bound to the power of the One Ring and completely under the dominion of Sauron. The Nazgûl arose as Sauron's most powerful servants in the Second Age of Middle-earth. They were once mortal men; three being "great lords" of Númenor. Sauron gave each of them one of nine Rings of Power. Ultimately, however, they were bound to the One Ring and completely enslaved by the will of Sauron.
Those who used the Nine Rings became mighty in their day, kings, sorcerers, and warriors of old. They obtained glory and great wealth, yet it turned to their undoing. They had, as it seemed, unending life, yet life became unendurable to them. They could walk, if they would, unseen by all eyes in this world beneath the sun, and they could see things in worlds invisible to mortal men; but too often they beheld only the phantoms and delusions of Sauron. And one by one, sooner or later, according to their native strength and to the good or evil of their wills in the beginning, they fell under the thraldom of the ring that they bore and of the domination of the One which was Sauron's. And they became forever invisible save to him that wore the Ruling Ring, and they entered into the realm of shadows. The Nazgûl were they, the Ringwraiths, the Úlairi, the Enemy's most terrible servants; darkness went with them, and they cried with the voices of death.>>
Re: APOD: NGC 6369: The Little Ghost Nebula (2017 Oct 28)
Posted: Sat Oct 28, 2017 9:17 pm
by jisles
It's Ophiuchus, not "Ophiucus".
John
