Escaping the light

THERE'S no doubt, the farther you are from the city lights, the better your stargazing will be. Light pollution robs us of the subtle beauties to be found in the night sky, whether it's the ribbon of stars and glowing gases of the Milky Way or the faint constellations of spring.

For instance, if you're in the city, you'd be hard-pressed to pick out groups like Virgo, low in the east, or Hydra's sprawling ladder of stars that now stretches from the southeast to the high southwest.

There are plenty of places in my province, Nova Scotia, where you can find dark skies. In fact, some of them rank among the best in Canada. More on that later. But there's good news for urban observers: light pollution doesn't affect planet observation. The sun does a great job of lighting up these objects for our enjoyment and even small details in planets' atmospheres and surfaces make it through the glare.

Of course, sometimes nearby lights that shine directly into your eyes can make even planet watching difficult. In that case, you have to do some creative positioning to use trees or structures to block these offending photons.

I usually drape an old blanket over deck rails or a high deck chair and sit on a lower chair in my attempts to shut out neighbours' porch lights or street illumination.

The most interesting planets to observe in a telescope, I think most observers would agree, would be Saturn and Jupiter.

While you need a telescope to enjoy Saturn's rings and surface features, a good pair of binoculars are enough to keep you coming back to Jupiter night after night. That's because its four brightest moons - Ganymede, Io, Callisto and Europa - are easily visible with just 10x power, although as tiny specks. You can detect changes in their positions over a matter of hours as they orbit around Jupiter.

This moon dance is obvious when you take another look on the following night - the lineup will likely be quite different.

If you're more ambitious and have your eye on objects a lot farther down the cosmic road than our solar system, such as galaxies, you must flee the light and seek out a nice dark spot in the country.

In Nova Scotia, it doesn't take too much of a drive to escape light blight,  even if you live in Halifax or Sydney. But you should get at least an hour's drive away from the city, since it doesn't take much sky glow to wash away detail in deep-sky objects.

Some of the province's dark sky areas are described on cleardarksky.com, a website that mainly focuses on weather and sky conditions for amateur astronomers. I say some because the website gets its light pollution information from the World Atlas of Artificial Night Sky Brightness, which oddly enough doesn't include Cape Breton and other parts of the province.

However, cleardarksky does indicate that areas such as Kejimkujik Natinoal Park in Queens County and the Argyle area near Yarmouth are little affected by light pollution. The Milky Way, the central region of our galaxy best visible in the summer, is so bright in these areas that it can cast shadows.

If you look at the entire light pollution map of North America, it's clear that this kind of observing is to be treasured.

While the Liscombe Game Sanctuary area on the Eastern Shore is one of those areas left out of the light pollution grading, it's well known among local amateur astronomers as an excellent dark-sky site.

As for Cape Breton, the skies over the East Bay and Bras d'Or area first tweaked my interest in stargazing, way back when. I can remember being more interested in the satellites and airplanes zooming across the sky, but I was also captivated by the glittering blanket of stars over the island hills. 

If you do find yourself a dark, safe place, and you have even a small telescope, you can observe many galaxies in April and May. Hundreds of galaxies are visible with a larger telescope in the Leo-Virgo region.

Two of the brightest in April, M65 and M66, can be found in the isosceles group that makes up the Lion's hindquarters. Find the star at the right bottom corner of the triangle, and look slightly below and to the left for M65 and M66. These two are so close together that they both fit into the viewing field of a small telescope.

It's worth escaping the city lights to marvel at these star cities so many light-years away.

Starry, starry night

Starry, starry night, 

Flaming flowers that brightly blaze,

Swirling clouds in violet haze,

Reflect in Vincent's eyes of china blue.

Vincent (Starry, Starry Night) - Don McLean

 

 

THE SUBJECT of the painting that inspired this pretty song can be seen in the east in our October skies.

But you may have to look hard for tiny Aries, the constellation that is seen with the crescent moon and Venus in Vincent van Gogh's painting Starry Night.

The Ram's three brightest stars are not that bright - they are arranged in a "broken stick" pattern that would easily escape the eye if the group weren't located in a barren patch of sky.

Van Gogh painted Starry Night in June 1889 at the Saint-Remy asylum, where he had himself committed after the famous breakdown that saw him cut off part of his left ear.

There's a fascinating side-by-side comparison of the painting and the constellation at http://www.vggallery.com/forum/forum_18a.htm.

 

It's not known why van Gogh chose this obscure constellation for his subject, although the online van Gogh gallery notes that Aries was the painter's astrological sign.

Turn a pair of binoculars or a telescope on Aries and the constellation becomes much more interesting. It's small enough that the three brightest stars will fit into the field of a 7 x 35 pair.

There are pleasing sprinklings of fainter stars surrounding the trio, particularly near the easternmost star, which forms a neat little triangle with two fainter stars in binoculars. If you like doubles, aim your telescope just below the westernmost star, the dimmest of the three, and you'll be rewarded with a tight pair of very similar stars.

If city lights make it difficult to find Aries, you'll likely have to seek darker skies to find the other inconspicuous trio in this region, Triangulum. Like Aries, this group will fit into view through wide-field binoculars.

When you try to pick out fainter constellations like these, you're putting a lot of things to the test, such as figuring out the faintest stars you can see in your area (the fancy term being limiting magnitude) and also how 'good' the atmosphere is that night (astronomers call this seeing). It also demonstrates how our eyes adapt to the dark.

For instance, on a September night way back when during a break at work, I was  three storeys above the street lights of downtown Halifax. It was a steady, clear night with low humidity - great conditions for stargazing. At first, I could see only the brightest star in Aries, nothing of Triangulum. But 10 minutes later, I could easily see the two brighter stars in Aries, with more difficulty its dimmest star, and all of Triangulum.

When I'm in the country, no dark adaptation is needed on this kind of night. Even faint constellations pop into view away from the scourge of light pollution.

Another thing about spotting fainter constellations - wait until they become higher in the sky, away from horizon glow and the air currents of the lower atmosphere. Spare your neck and do your high-sky gazing in a lounge chair with a blanket and maybe a warmed-up Magic Bag on these cooler nights.

The other faint constellations this month, Andromeda and Pegasus, couldn't be more different than the diminutive Aries and Triangulum. From Andromeda in the northeast to the western-stretching wings of the horse Pegasus, they take up a huge part of the sky.

The big square that makes up the body of the Pegasus starts to push the Summer Triangle off centre stage at the zenith in October. As geometrical contests go, there's none between the blazing trio of the triangle and the shy foursome that make up the Great Square.

But there are treasures hiding in that unassuming eastern sky.

Look above the middle star of the three that stretch out from the Square to find the Andromeda Galaxy, or M31. (Astrophotographer extraordinaire Blair MacDonald of Halifax made this amazing shot).  I can make out M31 in darker suburban skies with the naked eye, and on very good nights, I can spot this patch of fuzzy light in binoculars from Halifax.

It's a wonder to behold in my telescope at home - although if somebody new to astronomy looked in the eyepiece they might wonder what the fuss is about. Well, the thing is, the light from this fuzzy glow first started its journey toward our eyes two million years ago. Andromeda, somewhat bigger but quite similar to our own spiral galaxy, the Milky Way, is the most distant object we can see with the naked eye.

Northern exposure

Season of mists and mellow fruitfulness; close bosom–friend of the maturing sun. – John Keats, Ode to Autumn

HERE IN THIS season of changes, the night sky comes upon us ever more quickly and the days of bare–headed stargazing are fading fast.

The transitory nature of things has come close to home this autumn.

An old friend – a burly, blue– and yellow–eyed guy named Phoenix – has departed for the great catnip patch in the sky. Whenever my heart needs some warming up, I'll think of him dozing in a comfy patch of light from his favourite star, head nestled between his big white paws.

And a recent move has changed my astronomical ways. On the bright side (or dark, as it happens), we're temporarily even deeper in the sticks than our previous abode. While our new digs are being built, I'll enjoy probably the least light–polluted skies I've ever had.

The back deck now faces north – not usually a direction coveted by stargazers.

The northern horizon is on the opposite side of the sky from the richer parts of the Milky Way. Besides that, not much changes in this region. Many of the constellations are circumpolar, a fancy way of saying they never completely set.

The six circumpolar constellations slowly wheel around the North Star, Polaris, in a counter–clockwise motion throughout the year.

For example, probably the most famous star group, the Big Dipper, is now very low in the 7 o'clock position, and by next month will be striking about 6 o'clock.

The Big Dipper is part of Ursa Major, the Great Bear. The outside stars of the Big Dipper's bowl point up to Polaris, at the end of the Little Dipper's handle in Ursa Minor.

Keep tracing this imaginary line past Polaris and you'll come to the peak of the house–shaped constellation Cepheus (SEE–fee–us), the King.

If you've found Cepheus, your eye should certainly catch the brighter W–shape of Cassiopeia (kas–ee–oh–PEE–uh), right next door.

Probably the least known member of the circumpolar club is a real mouthful: Camelopardalis (kam–uh–low–PAR–da–lis), the Giraffe.

This is one tough beast to track down.

When I first got into this hobby, I thought I'd found the Giraffe with no problem. I looked up in the northeastern winter sky, saw a curving line of stars that seemed to form a long neck, with two stellar "legs" on either side. Hello, Camelopardalis.

No African savanna dweller here, though. I was actually looking at Perseus, the mythological hero equipped with sword and shield.

This glittering constellation is now low in the northeast just after dark.

You can use Perseus to find the real giraffe, which is so faint it's not on our star chart.

Camelopardalis is just to the left of Perseus, a much dimmer version of its wishbone shape.

Another elusive circumpolar beast, the faint and sprawling Draco (DRAY–ko) the Dragon, weaves its tail around the Little Dipper and arches up toward Cepheus. The Dragon's head lies farther west, perilously close to Hercules, the strongman demi–god who killed Draco.

 

Red planet redux


IT'S CAPTURED the imagination since the time of the Egyptians, who called the wandering "star" Har decher, the Red One. The Greeks and Romans, inspired by that distinctive bloody hue, named it after their gods of war.
As with most of the planets' names, the Romans had their way.

While Mars is perhaps the most intriguing planet, most thanks to  its prominence in fiction and movies, it's not usually an impressive object to the naked eye. While its rusty orange colour is eye-catching, it's a small planet and must be relatively close to the Earth to be bright enough to really stand out.

At about 6,800 kilometres in diameter, the rocky planet is only half the size of Earth. So even during close approaches, you need a good-sized telescope to make out specific features.Unlike Venus or the gas giants Jupiter and Saturn,  Mars doesn't have clouds in its atmosphere to reflect light back to observers on Earth.

But when it does get close enough, such as in 2001 and 2003, it's a a beautifully eerie sight.
A red filter on the telescope helps to bring out more detail.  And, as with any planetary observation, you should wait until Mars is high in the sky. Air currents near the horizon blur the image of any astronomical object.

Mars put on a fairly average show in 2013 and having moved into the constellation Pisces, it's now lost in the glare of the sun. Next year, our rocky neighbour will return to our evening sky, this time in the constellation Virgo.