Meteor showers occur several times each year but there is one that is popular with many skywatchers. That particular event is in August and is the Perseid Meteor Shower. Summertime observers spend hours in mid-August every year looking up into the night sky in anticipation of seeing a brilliant flash of light against the multitude of background stars.
This shower is favoured over the others as it occurs in the summer season. People are generally outside enjoying the cooler nighttime temperatures under the dark skies camping, canoeing or just vacationing at camp. Once the activities of the day are done we generally relax outside with our favourite beverage. The days are now becoming shorter and the evenings a bit cooler. This gives us the opportunity to gaze skyward to the heavens a little earlier in the evening once the sun has gone down.
This year the Perseid meteors peak on the night of August 12-13. Since this peak is quite broad the meteors can be seen a few nights before and after the maximum. These meteors are referred to as “falling” or “shooting” stars by many people but are really dust left behind Comet 109/P Swift-Tuttle as it travels around the sun. The numbers of meteors seen at maximum is generally around 50 to 60 meteors per hour from a dark sky site. From an urban area an observer may see 6 to 8 meteors over an hour. Many of the meteors associated with the Perseids are faint but a few of these can be quite bright and leave spectacular trains (trails left behind the meteor as it burns up in the atmosphere). Some of these trains are visible in binoculars for 5 minutes after the meteor has passed.
This year the new moon of August comes on the 12th. The absence of the moon in the night sky will ensure a nice dark sky in which to see even the faint meteors of the shower as observed from a rural setting (weather permitting of course). If the moon is present in the sky during a meteor shower then the faint meteors tend to be washed out in the moonglow. Observing from the city will definitely decrease the number of meteors seen due to the urban ambient light pollution of the night sky.
The best time to look for the meteors will be after midnight and before the first light of dawn when the radiant is higher in the sky and the Earth is heading into the meteor stream. The Perseids can be seen in any direction but looking generally northeastwards will result in more meteors but shorter meteor trails. Perseid meteors originate from a specific point in the sky called the radiant. The Perseid radiant is located between the constellations Perseus and Cassiopeia hence the name of the Perseid Meteor Shower. Following a meteor trail backwards in the sky to this point identifies it as a Perseid while any other meteors are sporadic (random meteors).
The planet Jupiter will be seen as a bright yellow “star” dominating the southern sky after the sun goes down. Look just below Jupiter to see Antares the brightest star in the constellation of Scorpius. Jupiter’s yellow colour comes from the sunlight reflected back to Earth from the giant planet. A small telescope will reveal the Galilean moons of Jupiter along with some of the bands in the planet’s atmosphere. Antares is a red supergiant star with a surface temperature of around 3,000 degrees C. which shines by its own light thus appearing reddish orange in colour. (Planets shine by reflecting the light of the sun while stars shine by radiating their own light.) Antares is 700 times larger and 10,000 times brighter than the sun. Its distance of about 600 light-years gives it a magnitude of 1.06 as seen from here on Earth.
Mars rises in the east around 1:30 a.m. at the beginning of August. The planet is brightening as it heads for opposition in late December. Its rusty red colour will contrast nicely with the icy blue colour of the Pleiades cluster stars as the Red Planet passes by them around August 7. Mars drifts by the star Aldebaran in Taurus around the 20th of August. Note the similarity in colour but Mars will be twice as bright (magnitude +0.3) as Aldebaran (magnitude +0.9).
For interested stargazers who happen to be at
If the weather permits we will conduct a sky tour of the constellations and stars along with some meteor watching following the presentations.
A total lunar
eclipse will occur on August 28. The moon will set during the eclipse as seen
from
Clear Skies
Ted Bronson