- By John Hlynialuk

This year, the summer solstice happens on June 21 at 1:25 pm EDT. It is the official start of the summer season in the northern hemisphere and winter in the southern. The Bluewater Astronomical Society and several local Tai Chi clubs will celebrate the arrival of summer at an eminently suitable location, the monolithic stone circle called Keppel Henge at the Keppelcroft Gardens in Big Bay. You are welcome to join us.

The informal event starts around noon on Thursday, June 21 and BAS members will bring telescopes for safe, closeup solar viewing while we wait for the shortest shadow of the year to cross the base of the summer solstice marker stone. Tai Chi enthusiasts find it inspiring to perform their exercises among the monoliths, the permanence of the stones providing a connection to the energy of the universe.

For me, the most striking effect of summer solstice is not philosophical but observational: the remarkable shortness of shadows on the ground. On June 21, an upright metre stick, for ex., has a shadow less than half as long, 38.6 cm. See the photograph for another example. For the next 6 months shadows at noon lengthen each day and by Dec 21, when the Sun is lowest in the sky, the shadow of a metre stick is a whopping 247.5 cm long!

Like all of us normal folks, amateur astronomers love to see the start of summer, but they have another reason to celebrate. Since the March equinox, the Sun has been appearing higher in the sky at noon in its daily arc from horizon to horizon. This increases the amount of light in our sky and reduces the amount of time we have under truly dark sky at night. There are only 9 hours of true night on March 21. And if a bright Moon is out, we lose an additional 2 weeks of dark nights every month. Many of us become lunar and planetary observers not by choice, but because the hundreds of fainter objects that we prefer to observe are blotted out by moonlight.

By the third week of June, the 9 hours of night sky in March, have been reduced to less than 4 hours. And it is not much consolation to know that some stargazers are worse off. Consider those north of the Arctic Circle. In June, in the Land of the Midnight Sun, with one super-bright star in the sky, there is no night time stargazing at all. True, 6 months later, there is a period of perpetual night, but the Arctic in the dead of winter and temperatures at -40 Celsius, dampens one's enthusiasm for outdoor activities.

After June 21, the hours of darkness start to increase and amateur astronomers in the northern hemisphere sigh: "Finally!" So, on the summer solstice, more than marking the start of summer, BAS stargazers will be celebrating the Sun starting to drop in elevation each day. A month from now, there will be about 5 hours of truly black skies, and by the equinox in September, we get 8½ hours of real stargazing. September is a favourite time for observing because the night-time bloodsuckers (mosquitoes and blackflies) are gone, the humidity has declined to manageable levels and the outdoor temperature is still comfortable. It is actually possible to go out after supper, get a few hours of serious stargazing (to the accompaniment of owls and coyotes instead of buzzing mosquitoes) and be back indoors before the 11 o'clock news. Compare that to June, when even at 10:30 pm the sky will show only a bright planet or two (Venus and Jupiter, right now) and it is still too bright to see the faint fuzzies that all amateur astronomers prefer. And then by 3 am, dawn twilight breaks above the eastern horizon!

So for me and my stargazing friends (all but the solar observers, anyway), June 21 is a time to celebrate the returning night, and we take each minute more of darkness and cherish it, -not something that most people would understand on what is often called "the longest day of the year." But know that astronomers are a forward-looking bunch and the last time our warm skin stuck to the cold metal of a telescope frozen by December temperatures is but a distant memory.

See you at noon June 21 at Keppel Henge, for some nice, warm, summer Sun-gazing!