Archive for April 23, 2010

Our spring almanac 23.04.2010 – 29.04.2010

Posted in astronomical time on April 23, 2010 by espacelab



St George’s Day
23.04.2010 is St George’s Day.

The flag of St. George, the English flag, flies atop the flagpole on the church tower in Kingsclere, but who was St George? What is believed to be the truth is that George was born in Cappadocia, an area which is now in Turkey, in the 3rd century; that his parents were Christians; and that when his father died, George’s mother returned to her native Palestine, taking George with her. George became a soldier in the Roman army and rose to the rank of Tribune. The Emperor of the day, Diocletian (245-313 AD), began a campaign against Christians at the very beginning of the 4th century. In about 303 AD George is said to have objected to this persecution and resigned his military post in protest. George tore up the Emperor’s order against Christians. This infuriated Diocletian, and George was imprisoned and tortured – but he refused to deny his faith. Eventually he was dragged through the streets of Diospolis (now Lydda) in Palestine and beheaded. It’s said that Diocletian’s wife was so impressed by George’s resilience that she became a Christian and that she too was executed for her faith.

The episode of St George and the Dragon was a legend brought back with the Crusaders. In this version, which appears as part of the the medieval bestseller, the Golden Legend, a dragon makes its nest at the spring that provides water for the city of “Silene” in Libya or the city of Lydda, depending on the source. The citizens had to dislodge the dragon from its nest for a time, to collect water, so, each day they offer the dragon at first a sheep, and if no sheep can be found, then a maiden must go instead of the sheep. The victim was chosen by drawing lots.

One day, this happened to be the princess. The king begs for her life to be spared, but to no avail, so she is offered to the dragon. then Saint George turns up on his travels, faces the dragon, protects himself with the sign of the cross, slays the dragon, and rescues the princess. The grateful citizens abandon their ancestral paganism and convert to Christianity.

Just like the story of Perseus and Andromeda.

A dragon in the night sky

Draco is a constellation in the far northern sky. Its name is Latin for dragon. Draco is circumpolar (that is, never setting) for many observers in the northern hemisphere. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations today.

In one of the more famous European myths, Draco represents Ladon, the dragon sometimes depicted with one hundred heads who guarded the golden apples of the Hesperides. The eleventh of the Twelve Labours of Heracles was to steal the golden apples. He put Ladon to sleep with music, which enabled Heracles to freely take the golden apples. According to the legend, Hera later placed the dragon in the sky as the constellation Draco.


The Cat’s Eye Nebula (NGC 6543) is a planetary nebula in the constellation of Draco. Structurally, it is one of the most complex nebulae known, with high-resolution Hubble Space Telescope observations revealing remarkable structures such as knots, jets, bubbles and sinewy arc-like features. In the center of the Cat’s Eye there is a bright and hot star, which around 1000 years ago lost its outer envelope producing the nebula.

Herakles – Hercules

Hercules was the Constellation Logo for Whitewater School. This constellation is close to the dragon in the night sky.






This a cluster of some of the stars drawn by the Whitewater School’s students. If you look in the star chart of Hercules you will see a sky object with the label M13. Messier 13 or M13, and sometimes called the Hercules Globular Cluster, is what is called a globular cluster in the constellation of Hercules. A globular cluster is a spherical collection of stars that orbits the centre of a galaxy in the same way as satellites orbit the Earth.


The Lyrids (continued)
The Lyrids are a strong meteor shower lasting from April 16 to April 26 each year. The radiant of the meteor shower is located in the constellation Lyra, peaking at April 22—hence they are also called the Alpha Lyrids or April Lyrids. The source of the meteor shower is the periodic Comet C/1861 G1 Thatcher.

Comets have a wide range of different orbital periods, ranging from just a few years to hundreds of thousands of years. Some rare hyperbolic comets have been found by calculations in celestial mechanics to pass only once through the inner Solar System before being thrown out into interstellar space along hyperbolic trajectories.

Short-period comets have been found to originate in the Kuiper Belt, or its associated scattered disc, which lie beyond the orbit of Neptune. Longer-period comets are thought to have their origins much further away in the Oort Cloud, a cloud of icy bodies at the outer boundaries of the Solar System that were left behind during the condensation of the solar nebula.

Clouds over Rotherwick


Looking across the fields to Rotherwick village 29.04.2010

Follow

Get every new post delivered to your Inbox.