hi all!
in this thread i will share overlays earned mainly from NASA-APOD page and SPACE.com.
the topic should be named as the sister of my earlier APOD - the best ever astronomy pics thread.
i am to put up overlays those are mean some improvement of the GSky imagery e.g.:

hope you will like it!
g


ATTENTION!
hi-res image overlays!
be patient when download!

making easier to pick one:
READ TOPIC THREADED!
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Credit: Adam Block, KPNO Visitor Program, NOAO, AURA, NSF

Explanation: The many spectacular colors of the Rho Ophiuchi (oh'-fee-yu-kee) clouds highlight the many processes that occur there. The blue regions shine primarily by reflected light. Blue light from the star Rho Ophiuchi and nearby stars reflects more efficiently off this portion of the nebula than red light. The Earth's daytime sky appears blue for the same reason. The red and yellow regions shine primarily because of emission from the nebula's atomic and molecular gas. Light from nearby blue stars - more energetic than the bright star Antares - knocks electrons away from the gas, which then shines when the electrons recombine with the gas. The dark regions are caused by dust grains - born in young stellar atmospheres - which effectively block light emitted behind them. The Rho Ophiuchi star clouds, well in front of the globular cluster M4 visible above on far lower left, are even more colorful than humans can see - the clouds emits light in every wavelength band from the radio to the gamma-ray.

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Credit & Copyright: WFI, MPG/ESO 2.2-m Telescope, La Silla, ESO

Explanation: The largest, most violent star forming region known in the whole Local Group of galaxies lies in our neighboring galaxy the Large Magellanic Cloud (LMC). Were the Tarantula Nebula at the distance of the Orion Nebula -- a local star forming region -- it would take up fully half the sky. Also called 30 Doradus, the red and pink gas indicates a massive emission nebula, although supernova remnants and dark nebula also exist there. The bright knot of stars left of center is called R136 and contains many of the most massive, hottest, and brightest stars known. The above image taken with the European Southern Observatory's (ESO's) Wide Field Imager is one of the most detailed ever of this vast star forming region. ESO has made it possible to fly around and into this detailed image by clicking here.

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NGC 253 is a large, almost edge-on spiral galaxy, and is one of the nearest galaxies beyond our local neighborhood of galaxies. This dramatic galaxy shows complex structures such as clumpy gas clouds, darkened dust lanes, and young, luminous central star clusters. These elements are typical of spiral galaxies. Caroline Herschel discovered NGC 253 in 1783 while looking for comets. The galaxy's closeness to Earth makes it an ideal target for amateur astronomers who can see the southern sky and for astronomers interested in learning more about the makeup of these stunning cities of stars. -credit-

more from wikipedia

NGC 7331 sits about 50 million light-years from Earth and has been billed as a twin of our own Milky Way galaxy because of its similar mass, star count and spiral arm shapes. Skywatchers Paul Mortfield and Dietmar Kupke recorded this view of NGC 7331 on Oct. 4, 2005 during a nightly observing program run by Kitt Peak. This image was featured as space.com's Image of the Day.

source: space.com, best selection

Credit: Digitized Sky Survey, ESA/ESO/NASA FITS Liberator
Color Composite: Davide De Martin (Skyfactory)

Explanation: Alnitak, Alnilam, and Mintaka, are the bright bluish stars from east to west (left to right) along the diagonal in this gorgeous cosmic vista. Otherwise known as the Belt of Orion, these three blue supergiant stars are hotter and much more massive than the Sun. They lie about 1,500 light-years away, born of Orion's well-studied interstellar clouds. In fact, clouds of gas and dust adrift in this region have intriguing and some surprisingly familiar shapes, including the dark Horsehead Nebula and Flame Nebula near Alnitak at the lower left. The famous Orion Nebula itself lies off the bottom of this star field that covers an impressive 4.4x3.5 degrees on the sky. The color picture was composited from digitized black and white photographic plates recorded through red and blue astronomical filters, with a computer synthesized green channel. The plates were taken using the Samuel Oschin Telescope, a wide-field survey instrument at Palomar Observatory, between 1987 and 1991.

more: NASA-APOD

M81 in Ursa Major

Credit & Copyright: Tony Hallas

One of the brightest galaxies in planet Earth's sky and similar in size to the Milky Way, big, beautiful spiral M81 lies 11.8 million light-years away in the northern constellation Ursa Major. This remarkably deep image of the region reveals details in the bright yellow core, but at the same time follows fainter features along the galaxy's gorgeous blue spiral arms and sweeping dust lanes. Above M81 lies a dwarf companion galaxy, Holmberg IX, sporting a large, pinkish star-forming region near the top. While M81 and Holmberg IX are seen through a foreground of stars in our own Milky Way galaxy, they are also seen here through a much fainter complex of dust clouds. The relatively unexplored clouds are likely only some hundreds of light-years distant and lie high above our galaxy's plane. Scattered through the image, especially at the the right, the dust clouds reflect the combined light of the Milky Way's stars and have been dubbed integrated flux nebulae.

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Credit & Copyright: Antonio Fernandez

Stars are battling gas and dust in the Lagoon Nebula but the photographers are winning. Also known as M8, this photogenic nebula is visible even without binoculars towards the constellation of Sagittarius. The energetic processes of star formation create not only the colors but the chaos. The red-glowing gas results from high-energy starlight striking interstellar hydrogen gas. The dark dust filaments that lace M8 were created in the atmospheres of cool giant stars and in the debris from supernovae explosions. The light from M8 we see today left about 5,000 years ago. Light takes about 50 years to cross this section of M8.

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Credit: NASA, ESA, A. Aloisi (STScI / ESA), Hubble Heritage (STScI / AURA) - ESA/Hubble Collaboration

Grand spiral galaxies often seem to get all the glory. Their newly formed, bright, blue star clusters along beautiful, symmetric spiral arms are guaranteed to attract attention. But small irregular galaxies form stars too, like NGC 4449, located about 12 million light-years away. In fact, this sharp Hubble Space Telescope close-up of the well-studied galaxy clearly demonstrates that reddish star forming regions and young blue star clusters are widespread. Less than 20,000 light-years across, the small island universe is similar in size, and often compared to our Milky Way's satellite galaxy, the Large Magellanic Cloud. NGC 4449 is a member of a group of galaxies found in the constellation Canes Venatici.

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Credit & Copyright: Ignacio de la Cueva Torregrosa

What creates the cosmic dust sculptures in the Rosette Nebula? Noted for the common beauty of its overall shape, parts of the Rosette Nebula, also known as NGC 2244, show beauty even when viewed up close. Visible above are globules of dark dust and gas that are slowly being eroded away by the energetic light and winds by nearby massive stars. Left alone long enough, the molecular-cloud globules would likely form stars and planets. The above image was taken in very specific colors of Sulfur (shaded red), Hydrogen (green), and Oxygen (blue). The Rosette Nebula spans about 50 light-years across, lies about 4,500 light-years away, and can be seen with a small telescope towards the constellation of the Unicorn (Monoceros).

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