[Bluearrowll]

What's in the sky tonight?
July 23, 2012

-As twilight behind to fade, use the Moon in the west-southwest to guide your way to Saturn, Spica, and Mars glimmering through the dusk (in that order of visibility) as shown below.

-Saturn (magnitude +0.8, in Virgo) shines in the southwest as the stars come out. Below it by 4½° is Spica, nearly the same brightness but twinklier. After dark they move lower to the west-southwest.

Astro Picture of the Day:
July 23, 2012

Source:
While hunting for comets in the skies above 18th century France, astronomer Charles Messier diligently kept a list of the things he encountered that were definitely not comets. This is number 27 on his now famous not-a-comet list. In fact, 21st century astronomers would identify it as a planetary nebula, but it's not a planet either, even though it may appear round and planet-like in a small telescope. Messier 27 (M27) is an excellent example of a gaseous emission nebula created as a sun-like star runs out of nuclear fuel in its core. The nebula forms as the star's outer layers are expelled into space, with a visible glow generated by atoms excited by the dying star's intense but invisible ultraviolet light. Known by the popular name of the Dumbbell Nebula, the beautifully symmetric interstellar gas cloud is over 2.5 light-years across and about 1,200 light-years away in the constellation Vulpecula. This impressive color composite highlights details within the well-studied central region and fainter, seldom imaged features in the nebula's outer halo. It incorporates broad and narrowband images recorded using filters sensitive to emission from sulfur, hydrogen and oxygen atoms. CAn you see the remaining core of the original star that created this nebula in the centre?