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.

2011 Constellation Guide: Auriga

Auriga

Symbolism: The Charioteer

Main Stars: 7

Position in the Sky

• Right Ascension: 6 hours
• Declination: 40 degrees
• Visible between latitudes 90 and -40 degrees
• Best seen in February (at 9:00 PM)

Named Stars

• Capella (Alpha Aur)
• Menkalinan (Beta Aur)
• Al Anz (Epsilon Aur)
• Haedi (Zeta Aur)
• Hoedus ll (Eta Aur)
• Hassaleh (Iota Aur)

Messier Objects

• M36:  Open cluster
• M37:  Open cluster, brightest in Auriga
• M38:  Open cluster, shape of greek Pi or a cross can be seen

Meteor Showers

• Alpha Aurigids - Range from August 25 to September 6 with maximum occurring on September 1.  Hourly Zenith Rate is about 9.
• Delta Aurigids - Run between September 22 to October 23 with maximum occurring between October 6-15.  HZR varies, possibley around 1 or less per hour.

Mythology
Greeks viewed the constellation of Auriga in light of the Athenian king Erichthonius.  Erichthonious was the son of the god of fire, Hephaestus, and was raised by Athene.  Athene taught Erichthonius to tame horses, and he became the first to attach four horses to a chariot., in imitation of the four-horse chariot of the sun.  This won the admiration of Zeus, and Erichthonioius was promised a place among the stars.
There is yet another story embedded within this constellation.  Capella, the brightest star in Auriga, and the sixth brightest in the sky, translates to"the she goat".  The star represents Amaltheia, the goat that suckled the infant Zeus.  The triangle of stars formed by Zeta, Eta and Epsiloni Aurigae are known as "the kids".
I've read that some early writers spoke of the Goat and Kids as seperate constellations, but since the time of Ptolemy they have been combined with the Charioteer, with the goat resting on his shoulder, and his arm supporting the kids.

Features
It is easiest to locate Auriga by first locating Taurus.  The tip of Taurus' right horn, Alnath, begins the bottom left of Auriga.  From this point, it is easy to connect-the-stars and visualize the hexagon.  I cannot offer any easy way to star hop to the three Messier objects, M36-38 other than that if you start with Alnath, and move upward about halfway to Theta Aurigae, you can move left and right to stumble upon the clusters.  Even at 48x, you;ll know when you see one of the clusters.  I will add that during my first outing viewing these objects, I had a difficult time confirming if I was seeing M36 or M38 because of nearby NGC 1907 (which can be seen in the same FOV).  M38 though is certainly a highlight, consisting of about 100 stars under magnitude 7.9.
Capella, the sixth brightest star in the sky is actually a quadruple star system (two binaries). Near Capella is the northernmost star of "the kids", Epsilon Aurigae.  This is one of the most fascinating stars in the sky.  Scientists still do not agree on the nature of this binary star.  Every 27 years the star enters a long and slow eclipse during which it dims from a magnitude 3 to 3.8.  It is agreed that it is an eclipsing binary, but the secondary star appears to have no affect on the light of Epsilon Aurigae.  Theories to explain the eclipse suggest that a disc of semi-transparent dust and gas pass between our view and the star.

Auriga with M36-38 enlarged

2011 Constellation Guide: Taurus

Taurus

• Symbolism: The Bull
• Main Stars: 19

Position in the sky

• RA: 4 hours
• DEC: 15 degrees
• Visible between latitudes 90 and -65 degrees
• Best seen in January (at 9:00 PM)

Named Stars

• Aldebaran (Alpha Tau)
• Alnath (Beta Tau)
• Hyadum l (Gamma Tau)
• Hyadum ll (Delta 1 Tau)
• Ain (Epsilon Tau)
• Alcyon (Eta Tau)
• Calaeno (16 Tau)
• Electa (17 Tau)
• Taygeta (19 Tau)
• Maia (20 Tau)
• Asterope (21 Tau)
• Sterope ll (22 Tau)
• Merope (23 Tau)
• Atlas (27 Tau)
• Pleione (28 Tau)

Messier Objects

• M1 The Crab Nebula 
• M45 The Pleiades

Meteor Showers

• Taurids
• Beta Taurids

Mythology

In Greek mythology, Taurus was identified with Zeus, who assumed the form of a white bull in order to seduce the legendary Phoenician princess, Europa.  It is told that Zues had Hermes take the king's cattle to the mountains near where the girls of Tyre played on the beach.  In the form of a bull, Zeus hid among the cattle awaiting his chance to abduct Europa.
Seeing how beautiful the bull was, she approached him with flowers and admired his muscular body.  The bull placed kisses on her hands, hardly able to contain himself.  As he laid down, Europa sat atop his back and he took off for the ocean.  Alarmed, but fearing she was helpless, Europa clung tightly to the bull as he swam to Crete.  Back on shore, Zeus revealed himself and seduced Europa, and adorned her with gifts such as a dog, who became Canis Major.
In artwork, it is only the front of Taurus which is displayed as the constellation; one argument is that it depicts the bull as partially submerged in water.  Actually though, there just is no room for the rest of the bull to exist in the sky; as Perseus stands just behind Taurus.

Features

Locating Taurus is just as easy as locating Orion.  To the west of Orion, the large V shape of his horns, tipped by the red giant Aldebaran ("the follower of the Pleiades") is hard to miss as it arcs across the sky.  From Aldebaran and looking east to the tip of the horn is the binary star, zeta Tau.  This star was known to the Babylonians as Shurnarkabti-sha-shutu, "the star in the bull towards the south".  Just above this star lies M1, the Crab Nebula.  
The Crab Nebula is a supernova remnant with a pulsar at it's center.  In your scope it will appear as a "faint fuzzy", as it's a magnitude 10 object, but if seeing is good you may be able to resolve the pulsar.  Today we see this object as the remnant of a supernova, but in 1054 astronomers in China and Arabia actually recorded the supernova event.  Being that the star was 6.5 light years from earth, it shown for 23 days in broad daylight, and for 2 years it was visible to the unaided eye at night.
The Hyades, an open star cluster (the closest cluster to our solar system) actually forms the V shape in Taurus with Aldebaran (but technically Aldebaran is not part of the Hyades).  In Greek mythology, the Hyades were the daughters of Atlas, and sisters of Hyas.  After grieving for the death of their brother, Hyas, the weeping sisters were put into the star cluster.  The significance of the sisters weeping relates to the Greek's belief that the rising and setting of the Hyades cluster was associated with rain (April showers, anyone?).
To the western part of Taurus is the most recognizable open cluster, the Pleiades, or the Seven Sisters.  The stars in this cluster are named for the seven sisters of Greek mythology; Sterope, Merope, Electra, Maia, Taygeta, Celaeno and Alcyone.  Viewing the cluster through a scope is a beautiful sight.  With good seeing conditions you can resolve the wisps of nebulosity surrounding the stars.  This reflection nebula is caused by dust reflecting the light from these young blue stars.

Taurus, M1, Hyades and the Pleiades.

2011 Constellation Guide: Orion

Orion

• Symbolism: Orion, the Hunter
• Main Stars: 7

Position in the Sky

• Right Ascension: 5 hours
• Declination: 5 degrees
• Visible between latitudes 85 and -75 degrees
• Best seen in January (at 9:00 PM)

Named Stars

• Betelgeuse (Alpha Ori)
• Rigel (Beta Ori)
• Bellatrix (Gamma Ori)
• Mintaka (Delta Ori)
• Alnilam (Epsilon Ori)
• Alnitak (Zeta Ori)
• Saiph(Kappa Ori)

Messier Objects

• M42 The Great Orion Nebula (diffuse nebula)
• M43 part of the Orion Nebula, de Mairan's Nebula (diffuse nebula)
• M78 (diffuse nebula)

Meteor Showers

• Orionids
• Around October 21st annually , the Orionid meteor shower reaches its peak. The meteors originate from Orion's border with Gemini. The zenithal hourly rate is about 20.
• Chi Orionids
• Peaks around December 2nd with a ZHR of about 3.

Mythology

The Greek poet Hesiod says that Orion was the son of Euryale, the daughter of Minos, and of Poseidon, and that there was given him as a gift the power of walking upon the waves as though upon land. When he was come to Chios, he outraged Merope, the daughter of Oenopion, being drunken; but Oenopion when he learned of it was greatly vexed at the outrage and blinded him and cast him out of the country. Then he came to Lemnos as a beggar and there met Hephaestus who took pity on him and gave him Cedalion his own servant to guide him. So Orion took Cedalion upon his shoulders and used to carry him about while he pointed out the roads. Then he came to the east and appears to have met Helius (the Sun) and to have been healed, and so returned back again to Oenopion to punish him; but Oenopion was hidden away by his people underground. Being disappointed, then, in his search for the king, Orion went away to Crete and spent his time hunting in company with Artemis and Leto. It seems that he threatened to kill every beast there was on earth; whereupon, in her anger, Earth sent up against him a scorpion of very great size by which he was stung and so perished. After this Zeus, at one prayer of Artemis and Leto, put him among the stars, because of his manliness, and the scorpion also as a memorial of him and of what had occurred.

Features

Orion is one of the most recognizable constellations in the sky, home to some of the brightest stars, and a few deep-sky objects, most notably the Orion Nebula.  You can easily locate Orion by looking southward to his right shoulder; Betelgeuse, a variable red supergiant, averaging around the 9th brightest star in the sky, and the 2nd  brightest in the constellation.  Going west to his left shoulder is Bellatrix, the 3rd brightest star in Orion.  Bellatrix is the 27th brightest star in the sky.  It is also known as the Amazon Star. It was once thought to belong to the same group as the stars of Orion’s belt; Alnitak, Alnilam, and Mintaka, but this is no longer believed to be the case.  Looking southwest to the left foot is Rigel, the brightest star in the constellation and the 6th  brightest in the sky.  Across to the east you’ll find the right foot; Saiph. The name is from the Arabic saif al jabbar; sword of the giant.
Crossing Orion’s waist from east to west is Alnitak, Alnihim and Mintaka; together this group creates Orion’s Belt.  These stars may also be named the Three Kings or the Three Marys.  They also mark the northern night sky when the sun is at its lowest point, and were a clear marker for ancient timekeeping.  Hanging from Orion’s Belt is his sword; containing the breathtaking Orion Nebula. This is one of the brightest nebulae in the sky, and can be viewed by the unaided eye. It is also an active star forming region; new stars are currently being born there. The most notable feature of the Orion Nebula is the Trapezium. This is a tight open cluster of stars right in the center of the nebula. If you can resolve the 5 major stars of this cluster, you have very good seeing.
The Horsehead Nebula is located just south of Alnitak. It is a dark nebula; a cloud so dense that it blocks the light behind it. The nebula was given its name due to the shape that the swirling gas and dust form; it looks like a horses head! The red glow comes from the hydrogen gas reflecting the light from the nearby star Sigma Orionis. There are also new stars forming in this nebula.

Looking south to Orion.  Orion and Horsehead Nebula enlarged.

2011 Constellation Guide

It's been far too long since my last post.  I've spent time working on other projects and spending time with my daughter.  I did however, come up with a new idea for this blog which will help keep my posts somewhat regular, at least monthly.  I'm going to post month-by-month a guide to the major northern constellations.  There are plenty of us new and experienced sky watchers who may be familiar with deep-sky objects and star hoping, but perhaps don't really know the constellations, their stories, and what treasures lie within their boundaries. Therefore, each month I will present one or more constellations which can be best viewed by 9:00 PM for the corresponding month.  Why 9:00 PM?  That should be about when the constellation will be at its highest in the sky (locally) - it's much easier to view that way.  Now, It's already February, so I'm already behind.  I will soon post about our first constellation; Orion.