Cygnus – the swan

The constellation Cygnus is a large swan, flying southward along the summer plane of the Milky Way. There is a dark lane that separates the cloudy path of our galaxy into two parts here. It’s known as the Great Rift. Although it looks like a divided highway, the dark part is really a long cloud of dust that is blocking our view of the distant stars in that direction. Galactic dust is very efficient at blocking starlight because the dust grains are tiny, like the wavelengths of light, and thus magnetic resonance increases the likelihood of scattering. Infrared and radio waves penetrate pretty well though.

The body of the bird is also known as the northern cross, which is huge compared to the more famous southern cross. The star on top of the cross, which is the tail of the swan, is Deneb and it’s one of the three brightest stars of summer. It’s 3200 light-years away which is a long way off for a bright star. Almost all the stars you see naked eye are in our own cul-de-sac. Deneb is across town, relatively speaking. For example consider the brightest star of summer, Vega. It’s only 25 light-years away. Bright star number three of summer is Altair, which is a bit less than 17 light-years away. The three-some, Deneb, Vega, and Altair are called the summer triangle. They are typically the first stars you see every summer night.

Albireo is the very tip of the swan’s nose and you’ll find it right in the center of the summer triangle. It is a popular point of interest for star hoppers, a must see of the summer tour. In a small scope you can see that it is actually two stars, one is topaz and the other one azure. Okay they’re gold and blue. Most of the colors in astronomy are rather subtle and understated but in this case they are fairly intense, shockingly so, especially to the sorts of folks who get excited about faint wisps of light in the distance.

NGC 7000 is called the North American Nebula because it thinks it is the most important nebula ever. As long as you are in the neighborhood, be sure to check out the Pelican right next to Florida. Also look for the Veil which is a couple of old fading bits of supernova, and the Coalsack which is a big batch of black crap.

Deep sky analysis of Cygnus has revealed the Hercules–Corona Borealis Great Wall, which is the biggest thing known to exist, short of the whole universe itself. It’s made out of galaxies, and clusters of galaxies, and clusters of clusters of galaxies. As big as it is, it’s not the sort of wall that can keep anything in or out. I guess you could say it’s mostly decorative.

Post completo en: Skywise Unlimited

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