Our winter almanac 19.02.2010 – 25.02.2010
Signs of Spring
The season of winter is still with us, but there are signs of spring growth in the appearance of snowdrops, daffodils and the crocus.
The ancient Greek poet Hesiod, writes about this time of year in his poem ‘Works and Days’. Hesiod speaks of Zeus completing the sixty days of winter after the winter solstice, and of how we can see the star Arcturus rising at dusk out of the Ocean Stream that surrounds all the lands of Earth. Then he speaks of a time when the swallows come, or Pandion’s daughter, as he calls the swallow, named after Philomela who was changed into a swallow in a tragic tale.
When Zeus has finished sixty wintry days after the solstice, then the star Arcturus leaves the holy stream of Ocean and first rises brilliant at dusk. After him the shrilly wailing daughter of Pandion, the swallow, appears to men when spring is just
beginning. Before she comes, prune the vines, for it is best so.
The star Arcturus is visible low on the eastern horizon about 23h (11pm) as one of the stars that make the star pattern of Bootes the Herdsman. As spring arrives it stands out more and more in the north-eastern sky after sunset. The ancient Greeks, like the poet Hesiod, looked to the appearance of stars in the night sky as a sign of the changing year.
The star Arcturus stands out among the many visible stars in the night sky as the brightest star in the northern hemisphere of the sky. This is why the appearance of Arcturus had such importance for people like Hesiod, because it is a clear and easily identifiable sign of the coming of spring, and a reminder to people who depend on growing crops for a living to prune the vines ready for the spring growth.
Arcturus is the brightest star in the constellation Boötes. It is also the third brightest star in the night sky, after Sirius and Canopus. It is, however, fainter than the combined light of the two main components of Alpha Centauri, which are too close together for the eye to resolve as separate sources of light, making Arcturus appear to be the fourth brightest. It is the second brightest star visible from northern latitudes and the brightest star in the northern celestial hemisphere.
Arcturus is an orange giant star. A giant star is a star with substantially larger radius and luminosity than a main sequence star of the same surface temperature. Typically, giant stars have radii between 10 and 100 solar radii and luminosities between 10 and 1,000 times that of the Sun.
In astronomy, an asterism is a pattern of stars seen in Earth’s sky which is not an official constellation. Like constellations, they are composed of stars which, while they are in the same general direction, are not physically related, often being at significantly different distances from Earth. An asterism may be composed of stars from one or more constellations. Their mostly simple shapes and few stars make these patterns easy to identify, and thus particularly useful to those just learning to orient themselves when viewing the night sky.
The Winter Hexagon is an asterism appearing to be in the form of a hexagon with vertices at Rigel, Aldebaran, Capella, Pollux/Castor, Procyon, and Sirius.
Gemini was the Constellation logo for Castle Hill School.. Gemini is one of the official constellations of the zodiac. Its name is Latin for “twins”, and it is associated with the twins Castor and Pollux in Greek mythology. In the myth the twins shared the same mother but had different fathers which meant that Pollux was immortal and Castor was mortal. When Castor died, Pollux asked Zeus to let him share his own immortality with his twin to keep them together and they were transformed into the Gemini constellation.
Gemini is dominated by Castor and Pollux, two bright stars that appear relatively close together, encouraging the mythological link between the constellation and twinship. The twin to the right is Castor, whose brightest star is α Geminorum (more commonly called Castor), is of the second magnitude, and represents Castor’s head. The twin to the left is Pollux, whose brightest star is β Geminorum (more commonly called Pollux), is of the first magnitude, and represents Pollux’s head. Furthermore, the other stars can be visualized as two parallel lines descending from the two main stars, making it look like two figures.
For one of Castle Hill’s students the arrangement of stars became the constellation Bart!