Posted by: Mario Carr | May 18, 2010

The night sky in May 2010

As our earth makes its journey around the sun new constellations appear in the spring night sky. 

From our perspective it looks as though the sun is moving in relation to the stars.  The apparent path of the sun is called the ecliptic and coincidentally it is also the same path that the moon and planets follow.  The ecliptic also crosses the zodiac constellations.  Virgo, Leo, Cancer and Gemini are spring zodiac constellation that can be seen in May.

Finding them is easy.  If you’re outside during a clear night in the early evening this month face south, look overhead and find the Big Dipper.  Arc an imaginary line down to the horizon from the Big Dipper’s handle until you hit the brightest star in the spring sky Arcturus.  The star is 37 light years away and is in the constellation Bootes the herdsman. 

In space, distances are measured in light years.  What I find really fascinating about astronomy are the incredible distances.  Everything is measured in light years.  That’s because nothing is faster than light.  In one year, light travels about 9.46 trillion kilometers. That’s like going around the earth 240 million times.

Spike your imaginary line even further down to the next bight star, Spica in Virgo the virgin.  Spica is about 260 light years away.  But if you believe in horoscopes, which have nothing to do with astronomy, you might say wait a second, I was born in September why is my sign Virgo if it is spring constellation.  Well, in September, Virgo is behind the sun and that is how your sign is determined.

If you look closely above Virgo with a small telescope you will see a patch of sky that is home to more than 1,300 galaxies called the Virgo Cluster.  M64, the Black Eye Galaxy and spiral galaxy M100 are just some galaxies that reside in the Virgo Cluster.  M100 is about 150 million light years away with more than 100 billion stars.

The Virgo Custer is extremely massive and its gravitational attraction actually slows down nearby galaxies.  Its mass was determined from its motion which moves at an astonishing rate of 1,600 kilometers per second. 

Most of these galaxies were discovered in the 1770s.  Slightly below Virgo is the famous Sombrero Galaxy.  It is about 40 million light years away and is an edge on spiral galaxy with a dark dust line running across its centre to give an impression of a Sombrero.

Spica lies close to the ecliptic.  If you follow the ecliptic to the right you will find the star Regulus in the constellation Leo.  Saturn lies in Leo.   Follow the ecliptic further and you will find Cancer and Gemini.

Here are a few dates to keep in mind.

May 14 – New Moon and Hamilton Amateur Astronomers meeting at  7:30 pm, Hamilton Spectator Building, 44 Frid St.

May 16  – Venus is close to the moon.  Venus appears in the western sky after dusk throughout the month.

May 26  –  Mercury is at its greatest elongation and can be seen during the morning throughout the month.

May 27 – Full moon.

For more information please see the Hamilton Amateur Astronomer’s web site at or call (905) 627-4323.



Hubble image of the Sombrero galaxy

Hubble image of the Black Eye Galaxy M64

Hubble image of the Spiral Galaxy M100


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