Sunday, August 14, 2011

Night Sky.

I have always loved stargazing. Growing up with a cabin, I had access to reasonably dark skies. There is a little bit of light pollution from the nearest towns near the horizon, but it is dark enough to see hundreds of stars - constellations are there if you know where to look, shooting stars if you're lucky, and Northern Lights if you are willing to brave cold, snowy winter nights.

Taking pictures of the night sky isn't easy (you'll want to click on the pics to make them bigger). Long exposure time means any light pollution can spoil your shot, even if it is barely visible to the naked eye. A tripod is a must, because it is impossible to hold a camera still for even 2 seconds, let alone 20 or 30. I haven't mastered star pictures by any stretch of the imagination... any longer than 20 seconds and the bright stars turn into big dots. (And don't even get me started on the Moon! Haven't figured that one out yet...)

Late September view of the Big Dipper
with light pollution from Camrose
 The Big Dipper is a fairly iconic constellation. It is often visible in cities in the winter time when it gets dark fairly early. The fact that it always appears in the same general vicinity of a Canadian sky makes it relatively easy to find. (Just look North! It's gotta be there somewhere...)

However, many people are at a loss to recognize other constellations. They can recognize the names, sure (usually those associated with the zodiac, like Gemini, Capricorn, and so on), but are at a loss to point them out in the night sky. Even looking at a star chart where the lines are drawn in is difficult ("it's an x... how is it supposed to be a swan?")

(left to right) Sirius, Orion, Taurus
Late December view facing South-West

Same picture, but labelled
 Since the advent of reliable, widespread electricity, our nights are not dark. Few of us have ever experienced true darkness. Take a "city dweller" out into the country and the awe they experience is telling - few of us actually know what the night sky looks like. That our ancestors were mesmerized and believed that the heavens could foretell events becomes much more understandable when a black velvet sky is littered with a multitude of stars. That they were able to navigate the stars and record their movements seems incredible.

These are remarkable feats, but with no light pollution, and few other activities to do in the dark, it is less surprising that the Arab astronomers (who assigned most of the names I've labelled - "al" is Arabic for "the". "Aldebaran" is "The Follower" while "Algol" is "The Ogre". In the constellation Perseus, he is depitcted holding Medusa's head.) were able to actually identify the color of individual stars, and pick planets out from the background stars. (In some of the pictures I took, you can just make out the fact that some of the stars are red, and some are blue. Betelgeuse, for example, is a red giant.)


(left to right) Orion, Taurus, Pleiades, Perseus
Late December view facing South-West
 

Labelled.
 The summer skies in Canada are pretty dull compared to the winter skies. Fewer of the really bright stars are visible in the summer, which means fewer landmarks help you identify stars... plus it doesn't get "dark" until really late. The winter sky is much more interesting (and it gets dark nice and early! Great for star gazing). Orion is a fairly obvious constellation, even if all you can make out are the three stars that make up his belt. (Orion's "Nebula" also known as "M42" is the bright fuzzy patch that appears to be hanging just below his belt. I challenge you not to giggle when you look at his "sword" the next time you go outside...)

As long as you can find Orion, it's fairly easy to identify other interesting objects in the winter sky. Located to the right of Orion is a very bright star (Aldebaran, part of Taurus). Aldebaran is located about half way between Orion and the Pleiades, a star cluster. To the naked eye, it looks a little bit like a small, squashed Big Dipper. In Greek mythology, the Pleiades (or Seven Sisters) were nymphs chased by Orion.

While it is still summer, when winter inevitably rolls around again try to get outside and expand your knowledge of the night sky. It might give you a greater respect for the astronomers of the past, and will definetly make the hot chocolate when you head back inside much more satisfying.

1 comment:

Julia said...

Sandi, this is amazing! The pictures you took with your camera of the night sky is something I've been trying to do with my camera for years.

Your posts are awesome girl. Keep it up!