Last month we introduced you to the concept of astronomy without visual augmentation. Telescopes are terrific, but can be expensive and need to be properly aligned with due north. A good pair of astronomical binoculars will set you back a pretty penny, and not all binoculars are equal to the task of passing faint starlight through their lenses.
Fortunately a number of periodic events are best viewed without either.
Number one on the list are meteor showers, the left-overs from passing comets. Meteors are the dust and small pebbles left in the wake of comets that have come close to the earth’s orbit at some time in the past. As they enter the atmosphere, they burn up, often spectacularly. There are a number of regular showers each year. The Delta Aquarids peak around July 28 each year. These meteors are known for long paths. The Perseids, due between late July and the middle of August (peak around August 12) are perhaps the best of the bunch, consistently producing upwards of 30 meteors per hour at their peak. Many sport long trains, and quite a few will be brilliant.
Comets themselves are balls of ice and dirt that have circled the sun for eons in a ‘cloud’ far outside the orbit of Pluto, our eighth-and-a-half planet. Nudged by chance gravitational influences, some begin a long fall toward the sun. As they reach the inner solar system, the sun’s heat causes the ice to melt and create a coma around the head of the comet, and a tail pointing away from the Sun. Some of these comets actually make it close enough to be spotted by astronomers, who are mostly amateurs. A very few comets grow to regal magnificence, but many others fail to produce a display worthy of expectations. In ancient times comets were thought to be harbingers or omens, but – as in the case of the comet of 1066 – one man’s omen of doom is another’s trumpet of glory.
An aurora occurs when the sun throws off a blast of energy known as a coronal mass ejection. Sunlight takes about eight minutes to reach the earth, but the particles that erupt from the surface in a CME take between 16 and 30 hours to reach us, giving us plenty of time to go looking for aurorae. These can be seen at almost any latitude, depending on how extreme the event is. They resemble curtains of light – usually green, but sometimes blue and red – dancing across large swaths of the night sky.
Friday, June 13 at 7:30 p.m. at the Sunshine Coast Arts Centre, Trail and Medusa, Sechelt, club member and UBC Professor Emeritus of Astronomy and Physics, Garth Jones, will discuss “Cosmic Distances” – explaining how the awesome distances of the universe are measured. Astronomical Society club meeting. Everyone welcome. Donations gratefully appreciated.
Join the discussion at the Astro Café at 8:30 p.m. on Friday, June 20 at Pier 17 in Davis Bay. Weather permitting, telescopes will be set up on the seawalk.
Submitted by the Royal Astronomical Society – Sunshine Coast (www.coastastronomy.ca)