Holiday Gift to Stargazers: The Christmas Sky

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The Yuletide evening sky is especially rewarding, with much of the eastern swathe filled with brilliant stars — sort of a celestialChristmas tree.

 


Distinctive groupings of stars forming part of the recognizedconstellation outlines, or lying within their boundaries, are known as asterisms. Ranging in size from sprawling naked-eye figures to minute stellar settings, they are found in every quarter of the sky and at all seasons of the year. 

The larger asterisms — ones like the Big Dipper in Ursa Major and the Great Square of Pegasus — are often better known than their host constellations. One of the most famous is in the northwest these frosty December evenings

The Northern Cross

The brightest six stars of the constellation Cygnus (the Swan) — which was known simply as the “Bird” in ancient times — compose an asterism popularly called the Northern Cross. [Night Sky Observing Guide for December 2012 (Gallery)]

Bright Deneb decorates the top of the Cross. Albereo, at the foot of the Cross, is really a pair of stars of beautifully contrasting colors: a third-magnitude orange star and its fifth-magnitude blue companion are clearly visible in even a low-power telescope. (In astronomy, lower magnitudes signify relatively brighter objects. Venus’ magnitude is around -5, for example, while the full moon’s is about -13.)

While usually regarded as a summertime pattern, the Northern Cross is best oriented for viewing now. It  appears to stand majestically upright on the northwest horizon at around 8:30 p.m. local time, forming an appropriate Christmas symbol. (And just before dawn on Easter morning, the cross lies on its side in the eastern sky.)

 

Written By: Joe Rao – Space.com
continue to source article at news.yahoo.com

8 COMMENTS

  1. I envy those who live in the southern hemisphere. My one experience looking into space on a light-free, cloudless night while visiting Heron Island showed an astonishing number of stars, compared to what we see – those of us who live “up north”.

  2. So much to see in the sky with the naked eye, and it is all beautiful, almost ‘magical’. I hope more people do look up, not enough do, and maybe get inspired to realise our cosmic insignificance. Maybe then we will start treating each other better since we will become more significant to each other. This is my Xmas and New Year wish for all, both freethinkers and believers.
    Merry Xmas and a Happy New Year to all!

  3. *In reply to #1 by rod-the-farmer

    Hi Rod, I can remember seeing both the northern sky and the southern sky (from the Falkland Islands) filled with stars.

    The trick is to find a clear night well away from ‘civilisation’. Even a village can give off enough light pollution to obscure billions of tiny stars.

    One of the most awe-struck moments of my life was lying in the summer grass looking at the night sky from a scout camp site somewhere in southern Britain. The camp was on a hill, well away from all kinds of dust and electric light, and the night was still with a crystal clear sky on all points of the compass.

    I was just old enough to know that every tiny pin-prick in the blanket of black night represented at least a star as big as our own Sun.

    The vastness of the Cosmos stretched out before us in every direction, the number of stars in the circle of my forefinger and thumb so numerous it was a hopeless task to count them.

    My senses were overwhelmed by the beauty, scale and tranquility.

    Peace.

  4. 20 years ago I drove form Paraburdoo in NW Australia 1500 km home to Perth; at 0200 stopped at the lookout near the Tropic of Capricorn, 200m above the plain. Not a light, no planes, so silent it was eerie. Stars were glittering icily even though the air was warm; for the first and only time in my life I experienced total silence and complete isolation from the human world. Utter insignificance, so powerful- almost religious!

  5. Nice article, learned a few things; but

    Venus…will remind those who rise early on 25 dec of the biblical “star in the east”

    Venus is in the eye of the beholder!

    On a side note, I think it is cool that there are 88 recognized constellations-same number as piano keys.

  6. In reply to #3 by Stephen of Wimbledon:

    The trick is to find a clear night well away from ‘civilisation’. Even a village can give off enough light pollution to obscure billions of tiny stars.

    One of the most awe-struck moments of my life was lying in the summer grass looking at the night sky from a scout camp site somewhere in southern Britain. The camp was on a hill, well away from all kinds of dust and electric light, and the night was still with a crystal clear sky on all points of the compass.

    The trick is to get away from the urban light pollution which reflects back from the clouds, air pollution, and the land.

    I recall one August, camping in a high valley hemmed in by mountains, with only the embers of a camp-fire for light.
    The sky was black-dark as we watched satellites pass by, and Perseid meteors burning up as streaks of light across the sky – against a background of billions of stars.

    So much of the night sky, is lost from view for city dwellers!

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