Hubble Space Telescope
"Orbiting the Earth since 1990, the Hubble Space Telescope has helped to answer some of the most compelling astronomical questions of our time, and uncovered mysteries we never knew existed. With vision that spans the ultraviolet through visible and into the near infrared, Hubble investigates everything from black holes to planets around other stars. Its unique capabilities are revolutionizing astronomy as Hubble continues humanity’s quest to explore the universe."(hubblesite.org)
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NGC 7293 "This infrared image from
NASA's Spitzer Space Telescope shows the Helix nebula, a cosmic starlet
often photographed by amateur astronomers for its vivid colors and eerie
resemblance to a giant eye. The nebula, located about 700
light-years away in the constellation Aquarius, belongs to a class of
objects called planetary nebulae. Planetary nebulae are actually the
remains of stars that once looked a lot like our sun. When sun-like
stars die, they puff out their outer gaseous layers. These layers are
heated by the hot core of the dead star, called a white dwarf, and shine
with infrared and visible-light colors. Our own sun will blossom into a
planetary nebula when it dies in about five billion
years."(spitzer.caltech.edu)NASA |
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The Cat's Eye Nebula or NGC 6543, is a
relatively bright planetary nebula in the northern constellation of
Draco, discovered by William Herschel on February 15, 1786. It was the
first planetary nebula whose spectrum was investigated by the English
amateur astronomer William Huggins, demonstrating that planetary nebulae
were gaseous and not stellar in nature. Structurally, the object has
had high-resolution images by the Hubble Space Telescope revealing
knots, jets, bubbles and complex arcs, being illuminated by the central
hot planetary nebula nucleus (PNN). It is a well-studied object that has
been observed from radio to X-ray.Wikipedia ( Composite image using
optical images from the HST and X-ray data from the Chandra X-ray
Observatory ) |
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The Horsehead Nebula (also known as
Barnard 33) is a small dark nebula in the constellation Orion.The nebula
is located just to the south of Alnitak, the easternmost star of
Orion's Belt, and is part of the much larger Orion Molecular Cloud
Complex. It appears within the southern region of the dense dust cloud
known as Lynds 1630, along the edge of the much larger, active
star-forming H II region called IC 434.The Horsehead Nebula is
approximately 422 parsecs or 1375 light years from Earth.It is one of
the most identifiable nebulae because of its resemblance to a horse's
head.Wikipedia (The Horsehead Nebula. The reflection nebula NGC 2023 is
in the bottom left corner and the nebula itself near the center, in the
shape of the head of a horse. - Interstellar dust of the Horsehead
Nebula as revealed by the Hubble Space Telescope.) |
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NGC 7635, also known as the Bubble Nebula,
Sharpless 162, or Caldwell 11, is an H II regionemission nebula in the
constellation Cassiopeia. It lies close to the direction of the open
cluster Messier 52. The "bubble" is created by the stellar wind from a
massive hot, 8.7 magnitude young central star, SAO 20575 (BD+60°2522).
The nebula is near a giant molecular cloud which contains the expansion
of the bubble nebula while itself being excited by the hot central star,
causing it to glow. It was discovered in 1787 by William Herschel. The
star BD+60°2522 is thought to have a mass of about 44 M☉. |
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The Cartwheel Galaxy (also known as ESO
350-40 or PGC 2248) is a lenticular galaxy and ring galaxy about 500
million light-years away in the constellation Sculptor. It is an
estimated 150,000 light-years diameter, and has a mass of about 2.9–4.8 ×
109 solar masses; its outer ring has a circular velocity of 217 km/s. It
was discovered by Fritz Zwicky in 1941. Zwicky considered his discovery
to be "one of the most complicated structures awaiting its explanation
on the basis of stellar dynamics." An estimation of the galaxy's span
resulted in a conclusion of 150,000 light years, which is slightly
smaller than the Milky Way.Wikipedia |
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Interacting peculiar galaxies. NGC 3808A
is the face-on spiral to the right. Material bridging the galaxies can
be seen and is evidence these two galaxies have passed close to each
other.Edge-on spiral is a background galaxy. This image was featured
on APOD Dec 9, 2015 and the APOD page has been translated into a few
languages.(remote-astrophotography.com) |
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Stephan's Quintet is a visual grouping of
five galaxies of which four form the first compact galaxy group ever
discovered. The group, visible in the constellation Pegasus, was
discovered by Édouard Stephan in 1877 at the Marseille Observatory.The
group is the most studied of all the compact galaxy groups. The
brightest member of the visual grouping is NGC 7320 that is shown to
have extensive H II regions, identified as red blobs, where active star
formation is occurring. Four of the five galaxies in Stephan's Quintet
form a physical association, Hickson Compact Group 92, and will likely
merge with each other. Radio observations in the early 1970s revealed a
mysterious filament of emission which lies in inter-galactic space
between the galaxies in the group. This same region is also detected in
the faint glow of ionized atomic hydrogen seen in the visible part of
the spectrum as a green arc. Wikipedia |
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