11 Best Celestial Events of 2011

Best Celestial Events of the Year

A Great Comet Coming?

We are due for a comet of the century. Is this it?

Last year brought a feast of celestial events that is difficult to beat. But the possibility of two naked-eye comets could elevate 2013 into a banner year for stargazing. Here are the highlights of what’s up in 2013.

By Alan Dyer

If we are very lucky, 2013 might end with a sight not seen in the sky for many decades: a comet bright enough to be easily observed in daylight. We have to look back to 1965, 1910, 1882, 1842, 1774 and 1680 to find the few comets that were as spectacular as Comet ISON has the potential to become.

But before reading further, please sign our legal disclaimer: Comet ISON could be stunning. Or it could be a dud. It might burst into brilliance as it rounds the Sun. Or it could fizzle and vaporize into nothing. Recent comets have done both, to the delight or disappointment of astronomy fans here on Earth. Remember, comets are agglomerations of ice and cosmic dust whose behaviour when heated can vary unpredictably.

Discovered on September 21, 2012, by astronomers with the International Scientific Optical Network (ISON), Comet C/2012 S1 is likely a first-time visitor from the distant Oort cloud. Its orbit will take it a searing 1.1 million kilometres—less than one solar diameter—from the Sun’s surface on November 28, 2013, its perihelion date. This makes it a member of the family of sungrazers that has produced some amazing comets in recorded history. Comet experts note that Comet ISON’s orbit is similar to the orbit of the Great Comet of 1680, which could be seen in daylight passing above the Sun. When it emerged into the evening sky, it shone at magnitude +2 (easily naked-eye, even in today’s urban light-polluted skies), with a tail 70 degrees long.

Whether Comet ISON performs as well remains to be seen. We won’t know until late 2013—not until after it rounds the Sun at the end of November—whether it lives up to the inevitable hype (and the idealized simulations shown here) or enters the history books as another celestial embarrassment for astronomers.

Some readers may remember a previous “comet of the century”: Comet Kohoutek was also to be a stunning sight around Christmas 1973. It fizzled, and very few people saw Kohoutek. It could happen again.

Click on photos to enlarge.

ALL IMAGES COURTESY STARRY NIGHT PRO PLUS™/SIMULATION CURRICULUM CORP.)

November 20

DAWN COMET

Comet ISON begins its apparition in the morning sky, brightening through October and November as it descends into the southeast on its approach to the Sun.

November 30

DAYLIGHT COMET? The comet rapidly whips around the Sun. Two days after its November 28 perihelion, it might be visible in daylight near the Sun in very clear skies.

Comet ISON reappearing in the December dusk

December 3

ENTERING THE EVENING SKY As Comet ISON pulls away from the Sun, it enters the evening sky and is well placed for northern observers. Will it be visible in bright twilight as shown here?

December 21

AT ITS BEST FOR CHRISTMAS? By solstice and the holiday season, Comet ISON has climbed high enough from the Sun and far enough away that it appears in a dark sky, perhaps as a fine naked-eye comet.

Comet ISON

ITS HAIRPIN TURN AROUND THE SUN
SHOOTING ROUND THE SUN This illustration shows the approximate path of Comet ISON relative to the Sun as seen from Canadian latitudes looking south each day at solar noon. The comet comes in from the west, shoots rapidly around the Sun in a hairpin turn, then climbs north away from the Sun. The comet may or may not survive its close passage near the Sun.

Comet ISON

ITS SUNGRAZING ORBIT
ELONGATED ORBIT Viewed from a point above Earth in space, we see how Comet ISON’s elongated orbit brings it into the inner solar system from below, then whips it up and around the Sun in a classic “sungrazing” orbit. If it survives and performs as some past sungrazers have, it could be at its most spectacular in the days—or weeks—following its November 28 perihelion. Or it could be vaporized into a dim cloud of dust.

Gravenhurst Muskoka Family Star Party 2013