STARRY NIGHTS
By Gary Boyle
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August 18, 2005
Under an August Sky
To choose one particular month for star gazing, August would be by far the best. This special time of year has many advantages over its eleven calendar cousins. Mix in a lovely combination of cool nightly temperatures; only a trickle of die hard mosquitoes and earlier sunsets makes this a fabulous time to head out with the family under the canopy of distant suns, gaze up and wonder.
August is the best month to view the annual Perseid meteor shower which took place this year on the nights of Aug 11/12 and 12/13. We actually had two opportunities as the peak of the display was at about 1:00 p.m. on the 12th. A meteor shower is the result of Earth passing through the dusty debris of a comet’s wake – its dust tail. As these icy mountains circle the sun, dust grains the size of sand particles is blown of the comet by solar winds creating the comet’s trail. If this area happens to intersect Earth’s plane as we orbit around the sun in our yearly tradition, us plow through the huge cloud comparable to a rain storm. During this brief period of hours and days we witness tens to hundreds of shooting stars in a single hour. The Perseids usually generate some 90 meteors per hour with speeds in the 70 km/sec range.
Whether you are a weekend camper, cottage owner or just someone who wants to get away from the city’s light dome, plan a few nights from Aug 27th and the entire week following into the Labour Day weekend. By then the moon will be past third quarter, rising around midnight and early morning hours. Therefore it will not be a hindrance and one can appreciate the darkened night sky in all its glory. On the first available clear night, step outdoors about an hour after sunset. Over the next few weeks, the two brightest planets of our solar system Jupiter and Venus (flanking to the western horizon) will inch closer to each other. On September 1st, Venus slides under Jupiter and will be separated by twice the moon’s width or one degree of sky.
If you have never seen a true country sky, prepare to be dazzled. One can see over 2,000 stars at any given time from a dark location in contrast to a couple of dozen from the city. Looking straight up, you should see a veil of light grey stretching down to the southern horizon – this is our home galaxy called the Milky Way. Appearing as a thin cloud is actually the glow of millions of distant stars too faint to be seen even with a telescope. Our galaxy like many others contains an estimated 100 billion (yes with a B) stars. It measures one hundred thousand light years in length. A light year is the distance light travels in a year or ten trillion (with a T) kilometres.
If you own a pair of binoculars be sure to pack them for the trip. These mini telescopes are the best way to start learning the sky from the large perspective. So do not under estimate them. Tens of thousand of stars can be observed with the simplest of binoculars. To avoid back problems, get a comfy reclining lawn chair and position yourself accordingly. Sweeping the heavens above, you will come across star clusters and gaseous nebulae.
Enjoy the floating feeling as you scan the Milky Way right down to the galactic centre in the south. The Milky Way arcs through an overhead constellation called the Northern Cross aka - Cygnus the Swan with the bird’s head (pointing south) mid body and tail feathers riding the Galactic veil. The Swan’s wings are in flight as positioned either side of the birds mid body. For those of you owning telescopes, set your sights on the head of the Swan. This gem is named Albireo and is the most beautiful double star in the entire sky. Spiral galaxies like the Milky Way have curled arms. When scanning the celestial veil on your nightly tour, look for individual arms with a darkened area in the middle called the Great Rift.
And finally, over the hours or so outside, you will come across many orbiting satellites and even the International Space Station. Your night might even light up with a magnificent display of Northern Lights. Keep checking northern skies from east to west. Auroras usually pop up around midnight when the sun is on the other side of the earth.
I would like to hear your experiences. Clear skies everyone.
Gary Boyle
garyboyle@sympatico.ca
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Gary Boyle is a freelance astronomy educator and writer. He teaches astronomy to adult and children as well as hosts many summertime ‘Star Nights’ at Provincial Parks and campgrounds.
Visit his web site at: www.wondersofastronomy.com
Send Questions & Comments about the Starry Nights to Gary Boyle
