This Saturday night (Mar.26) as neighbourhoods and city blocks turnoff their lights for Earth Hour why not take advantage of the darkness and look skyward at the stars. As long as you have clear skies, you should experience a lot less light pollution and so see a fair bit more stars in the sky than usual.
As a quick test for your sky conditions and the effects of light pollution, take a look at the Little Dipper and see how many of its stars you can see. To find Ursa Minor face the northeast horizon and look about halfway up the sky (mid-northern latitude locations).
You should be able to see the Big Dipper lying on its side with the handle pointing down towards the horizon. Take the 2 end stars in the bowl and draw an imaginary line left until you hit the next brightest star – which is the North Star or Polaris. It marks the tail end of the Little Dipper. Now try and trace out the remainder of the Little Dipper.
Can you see all the stars that make up the handle and bowl? Backyard astronomers use these stars to get a rough guage of how light polluted their local skies are. While the two end stars of the little bowl are magnitude 2 and 3 - making them just visible from suburban skies – the remaining two stars in the bowl and handle (except Polaris which is super bright at mag 2) are all 4th magnitude – which means they are usually not easily visible under lots of light pollution in urban and suburban sites. Look for the stars before all light are turned off for Earth Hour and then during Earth Hour. Do you see any difference?
Earth Hour will also be a great time to see the wonders of the Universe. One of the great celestial sights not to be missed is the granddaddy of all constellations – Orion – the Great hunter. Face the southwest sky and look for 3 bright stars in a row – that is Orion’s belt. Now just underneath it is his sword – made of three much fainter stars – usually more challenging to see under urban lighting. Can you see 3 faint stars lined up vertically? Look a the middle star and you may notice that its fuzzy. That’s because you are looking at a giant gas cloud that is a nursery for dozens of newborn stars. Called the Great Orion Nebula – its is located more than 1300 light years from Earth. You should be able to see it with the naked eye as a ‘fuzzy looking star’ – especially during Earth Hour.
Around Canada and the US there will be local astronomy clubs setting up telescopes in municipal parks during Earth Hour to take advantage of the darkness. I will be setting up my telescope with my astronomy buddies from RASC for free public viewings at the Westmount Park Earth Hour celebrations in Montreal. What’s happening in your neck of the woods? Check out the Royal Astronomical Society of Canada’s website and for the USA go online to the Night Sky Network and try the Astronomical League website too.
Let’s enjoy the dark skies – even if they are only for an hour!
Wishing you all clear skies!
Tags: big dipper, Earth Hour, light pollution, little dipper
Posted in Constellations, Stargazing, stars | Comments Off