2011 Constellation Guide: Gemini

Gemini

Symbolism:  The Twins

Main Stars: 17

Position in the Sky

• Right Ascension: 7 hours
• Declination:  20 degrees
• Visible between latitudes 90 and -60 degrees
• Best seen in February (at 9:00 PM)

Named Stars

• Castor (Alpha Gem)
• Pollux (Beta Gem)
• Alhena (Gamma Gem)
• Wasat (Delta Gem)
• Mebsuta (Epsilon Gem)
• Mekbuda (Zeta Gem)
• Propus (Eta Gem)
• Propus (Iota Gem)
• Tejat (Mu Gem)
• Alzirr (Xi Gem)
• Propus (1 Gem)

Messier Objects

• M35 - Open cluster

Meteor Showers

• Geminids - A major annual shower.  Ranges from as early as December 6 to December 18, with maximum on December 13/14.  Zenithal Hourly Rate can range from 50-80.
• Rho Geminids - A very minor shower.  Ranges from December 28 to January 28 with maximum around January 8.  ZHR less than 1.

Mythology

The proximity of Castor and Pollux drew attention of ancient astronomers around the globe, who almost always saw them as counterparts.  The Chinese saw them as the universal principals of Yin and Yang  The Egyptians saw them as a pair of plants, the Arabs as two peacocks, the Phoenicians as a pair of kids or gazelles.  The Romans sometimes associated them with Romulus and Remus, the founders of their nation.  The affiliation that has stuck depicts them as Castor and Pollux, known to the Greeks as the Dioscuri (sons of Zeus).  Members of Jason's crew of Argonauts, Castor and Pollux were 'half-twins' - their mother was Quen Leda of Sparta, but Castor's father was her husband King Tyndareus, while Pollux was fathered by Zeus, who came to Leda in the form of a swan.

Features
Gemini is pretty easy to locate thanks to its twin stars Castor and Pollux.  The Twins sit high above Orion, east of Taurus.  Castor may appear as a single star to the unaided eye, but a telescope will split the bright blue star into a pair, and may also reveal a third star, a magnitude 9.3 red dwarf.  Actually, Castor is a sextuple star system, but amateur equipment cannot reveal this.  Pollux is the brightest star in Gemini, and one of the brightest in the sky.  It is an orange super giant, and is known to have a planetary system.
Messier 35 is an open cluster, and a great object to see through your scope.  There are several hundred stars packed into an area of the sky about the size of the full Moon.  A faint object can be found east of Wasat, the Eskimo Nebula.  This is a magnitude 10 planetary nebula, and may be at the edge of vision for many suburban locations.  It will appear as a blue-green disc, but with large equipment you may be able to resolve the features in the gas

2011 Constellation Guide: Canis Major

Canis Major

Symbolism:  The Greater Dog

Main Stars:  8

Position in the Sky

• Right Ascension: 7h
• Declination:  -20 Degrees
• Visible between latitudes 60 and -90 degrees
• Best seen in February (at 9:00 PM)

Named Stars

• Sirius (Alpha CMa)
• Murzim (Beta CMa)
• Muliphen (Gamma CMa)
• Wezen (Delta CMa)
• Adara (Epsilon CMa)
• Furud (Zeta CMa)
• Aludra (Eta CMa)

Messier Objects

• M41 - Open cluster

Meteor Showers

• None

Mythology

Not much is written of Canis Major in the ways of mythology.  It is told by Eratosthenes and Hyginus that Canis Major symbolizes Laelaps, a dog of incredible speed.  One story tells of Zeus giving the dog to Europa, whose son, Minos passed it on to Procris.  Lealaps was given to Procris along with a magical javelin which could never miss its target.  Her husband, Cephalus used the javelin for hunting, and accidentally killed Procris with it.  Cephalus took the dog and traveled to Thebes, where it happened that a fox was ravaging the countryside.  Caphalus set Lealaps upon the fox, but the fox always remained just out of reach of the dog's bite.  Zeus, seeing no end to the chase set both animals to stone, and placed Laelaps among the stars.
Canis Major is also seen as a hunting companion to Orion; assisting him with fighting Taurus, or chasing Lepus, the hare.

You may find it interesting that the term "dog days of summer" originates from this constellation, particularly Sirius.  The Europeans and ancient Romans looked to Sirius rising just before the Sun to signal the start of the hot summer days (July - August).  Sirius, being the brightest star in the sky, was thought to be the source of the summer heat.  The ancient Egyptians associated with Sirius with the flooding of the Nile, and therefore noted Sirius a star of great importance.

Features
If locating Orion is easy, finding Canis Major is even easier.  When looking to the southern sky, your eyes should easily fall upon Sirius, the brightest star in the night sky.  Sirius represents the nose of Canis Major in some art, and in others it sits along the dog's breast.  In the images I provide here, Sirius marks the dog's breast, with his triangular head just above.

This constellation is simple and beautiful. It's lines are not complex, and is easy to identify.  The Milky Way flows right through Canis Major, which is beautiful in and of itself, but it blocks out any other deep sky objects that may otherwise be visible on the other side of our galaxy.  M41, the open cluster is visible though, and may be to the unaided eye.  This is the only Messier object in this constellation.  I enjoy looking to Canis Major because you don't need a telescope to appreciate all of its beauty.