This evening, earth will pass through the orbit of comet Swift-Tuttle, encountering debris left over by the comet each time it approaches the sun – every 130 years.
This debris rams into the upper atmosphere at the speed of 60 km per second, causing the air to ionise and shed bright streaks of light as the particles vaporise. These are meteors or shooting stars. This particular meteor shower has been observed for a long time and is known as the “Perseid Meteor Shower” or “Dmugh ta’ San Lawrenz”. The point in the sky – the radiant – where the meteors seem to originate lies in the constellation of Perseus, hence the name of the meteor shower, the Perseids.
This year, the first quarter moon sets in the late evening, leaving a dark sky for prime meteor watching during the hours from midnight until the first glimmer of dawn. It is estimated that the normal rate of the meteors is 60 every hour.
No equipment is needed to watch the meteors – only dark skies. When the radiant is still low in the northeast, the meteors enter the upper atmosphere at a low angle and few are visible. As the night advances and the radiant rises higher in the sky, the meteors fall straight down and a greater number can be seen.
The Astronomical Society Of Malta invites the public to join its members and observe the meteor shower from L-Ahrax tal-Mellieha, next to the chapel, from 10pm onwards tonight and tomorrow night. A power point presentation describing the meteor shower and the local folklore associated with it will be shown every hour near the chapel and telescopes will also be set up by society members for public use.
Various objects, such as nebulae, star clusters and also the planet Mars, can be seen through the telescope. Mars is fast nearing opposition and will soon be in line with Earth. This will take place on 7 November, but the closest approach to Earth will be on 30 October. Using a telescope with 80 times magnification, Mars will appear as big as a full moon to the eye.
For more information visit the website: www.maltastro.org