ARGO NAVIS - CONSTELLATION OF THE MONTH
HISTORY & MYTHOLOGY
The Argo Navis represents the ship piloted by Jason of the Argonauts during his quest for the Golden Fleece. The ship was said to be a gift from Athene and was constructed from Zeus’s sacred oak tree and housed 50 oars that were manned by 50 Greek heroes, including Castor, Pollux, Orpheus and Hercules.
Jason was the rightful air to the throne after his father was murdered by his uncle, Pelias. As a child, Jason was sent to the wise centaur, Chiron, and when he came of age, he vowed to reclaim his birthright. Pelias agreed to give up the throne if Jason could retrieve the Golden Fleece from Cochis, where it was guarded by a fearsome dragon. Jason gathered a crew of great Greek heros and set sail in the Argo Navis. Along the way, they encountered various dangers including the Sirens, Scylla and Charybdis, fire-breathing oxen and undead warriors!
The constellation is huge and dominates the southern sky, but in 1763, Nicolas De La Caille split it up into 3 parts, Carina (The Keel). Puppis (The Stern) and Vela (The Sail). All 3 constellations are hard to visualise but the area is rich in Deep Sky Objects thanks to the Milky Way running through it.
Canopus us the second brightest star in the sky and the brightest in the constellation of Carina, the Stern. It is a white giant with a diameter over 70x that of our Sun and shines more than 10,000x brighter. Canopus is situated around 300 light years away from Earth.
The bushmen called Canopus the 'Ant-Egg Star', since its arrival signified the best time to harvest this rich source of protein. To the Greeks, Canopus was named after the captain of the ship that rescued Helen of Troy during the Trojan War.
Canopus is in an area of sky devoid of any other bright stars and was thus considered an important navigational star in maritime history, as well as for the Voyager space probes that launched from Earth in the late 70's and are still operational today.
Eta Carina (Carina)
Eta Carina is one of the largest and most most studied stars in the sky. Eta Carina used to be the second brightest star in the sky in the mid 1800's before completely fading from view. It is now just visible to the naked eye close to the diamond cross asterism.
It is believed that Eta Carina, once a triple star system, underwent a near-cataclysmic merger with a smaller binary companion. The Great Eruption, as it became known, released a huge amount of energy, brightening the star dramatically. The star has since settled again but is assumed to one of a select few that is predicted to go supernova in the relatively near future.
Image Credit NASA/ESA/A.Feild
The star is over 7500 light years from Earth and this distance, coupled with the instellar dust in the Milky Way, limits its magnitude when viewed from Earth. However, astronomers consider Eta Carina to be one of the brightest stars known, shining at over 4 million times brighter than the Sun!
DEEP SKY OBJECTS
The Carina Nebula (Caldwell 92)
A huge emission nebula and star forming region occupying the area around the star, Eta Carina.
It is considered to be over 4x bigger and brighter than the famous Orion Nebula, M42.
The Southern Pleiades (Caldwell 102)
An open cluster of over 75 young stars that was discovered in 1751 by De La Caille from his observatory in South Africa.
The name stems from its superficial resemblance to the Pleiades in Taurus. Its shape more resembles that of the 5 of diamonds playing card.
Image Credit: Wikipedia
The Diamond Cluster (NGC 2516)
Situated over 1300 lights away from Earth, the Diamond Cluster is easily visible to the naked eye as a hazy patch at the tip of the asterism, the False Cross. The cluster contains over 100 stars, including 2 red gaints and 3 double stars. The main stars form an obvious diamond shape when viewed through a small telescope.
Image Credit: Astronomy.com
The Wishing Well Cluster (Caldwell 91)
This open cluster got its name from looking like a collection of silver coins shimmering in the water. C91 contains well over 150 stars residing over 1000 light years away. It was also discovered by De Lacaille from South Africa.
On 20th May 1990, the Wishing Well Cluster became the first object to be viewed with the Hubble Space Telescope.
Image Credit: Wikipedia