How to watch the Eta Aquariid meteor shower

Credit: NASA

Monday, May 5, 2014, 7:44 PM - There's a saying that goes 'early rising is its own reward,' but for this week there's a bonus thrown in. The Eta Aquariid meteor shower is reaching its peak over the next few days, so anyone venturing out in the hours just before dawn may be treated to a dazzling display, courtesy of Halley's Comet.

Although Halley's Comet only swings through the inner solar system every 75 years or so, each year in between, we here on Earth get two reminders of its visits. Like all comets, when Halley gets close to the Sun, a mixture of gases, ice, dust and rock gets blasted off of its surface. This combination forms the wide 'coma' that surrounds the comet's nucleus, the comet's tails, and it also gets left behind in a trail that follows the same trajectory of the comet. When Earth passes through one of these trails of debris, the bits of dust and rock hit our atmosphere travelling at anywhere from 40,000 to over 260,000 kilometres per hour. This compresses the air in front of the debris, causing the air to glow brightly. The pressure and heat sometimes vapourize part of or all of the bit of debris, and this can add elements to the mix that produce some interesting colours.

Every meteor shower we experience in a year comes from a comet (two even come from rock comets!), but Halley is one of the few that actually produce two of these showers, because it comes close enough to Earth's orbital on its way towards the sun and again on its way back out towards the outer solar system. In October and November of every year we encounter the part of the trail left behind as Halley approaches the Sun, so the 'bits' are flying at the night-side of the planet from the constellation Orion (these are the Orionids). In every April and May we pass through the trail the comet left as it was heading away from the Sun, so most of the bits come at the daylight side of the planet, but it's usually visible before dawn. 

The meteor shower has actually been going on for roughly two weeks now, but it's this week, for a few days before and after May 7, that the shower reaches its peak. Anyone under dark-sky conditions will likely see around 45 meteors per hour radiating from out from the constellation Aquarius as it rises in the east. The shower will then slowly taper off until the end of May, when Earth exits the debris field. 

The best way to view the shower is to head to somewhere without a lot of light pollution. In places like southwestern Ontario, southern Quebec and southern Alberta, that's not going to be an easy task (check out the typical light pollution experienced at this site). Anyone living around any large urban centre isn't going to see much either. There are several 'dark sky reserves' set up across the country, where people can go for the best skyviewing results (the Royal Astronomical Society of Canada keeps track of these).

If you can't get to one of these dark sky areas, at least getting away from large urban areas will give you a better chance to see at least some meteors. 

Check your local weather before venturing out and take a look at your local clear sky chart as well, since overcast skies will spoil the show. Pick an area that's relatively flat, without a lot of trees around, so you can see as much of the horizon as possible. Dress appropriately for the weather, since you're not likely to see much sitting in your car, and maybe bring some folding chairs so that you don't have to sit on the ground. Also, bring along some friends or loved ones, because these are always good events to share with others. The meteors will be radiating out from the east, but you'll likely see the most by facing east and then looking straight up. 

Southern Ontario Fireball

Although it's just speculation at this point, we may have actually had something special from this particular meteor shower. A fireball that streaked through the afternoon sky on Monday, east of Toronto, may have been something from the Halley's Comet debris stream hitting our atmosphere.