The 2015 Leonid meteor shower is expected to be at its best on the night of November 17-18. The predawn hours on November 18 are the optimum time, no matter where you live on the globe. Will you see what’s shown on the image at the top of this post? Thousands of meteors per hour? No. That image is from 1998, when the Leonids parent comet – Comet Temple-Tuttle – was nearby. The Leonids are famous for producing meteor storms when the comet is in our neighborhood, but no meteor storm is expected this year, only a modest 10 to 15 Leonid meteors per hour. There’s good news about this year’s shower, though. The moon will set at late evening, leaving dark skies from late night till dawn.
Here’s another tip regarding the radiant point. As darkness falls in mid-November, the radiant point of the shower sits below your horizon, as seen from all parts of Earth. As the Earth turns, the constellation Leo the Lion – carrying the meteor shower radiant point – will rise over your eastern horizon around midnight (or around 1:00 a.m. at temperate latitudes in the Southern Hemisphere). The Leonid meteors are few and far between around midnight, when the radiant point is at or near the horizon. Even so, this is the best time to try to catch a rare earthgrazer – a slow-moving and long-lasting meteor that travels horizontally across the sky. As Leo climbs much higher up in the dark hours before dawn, the meteors will fall more downward than sideways.
Just remember, you don’t have to locate a meteor shower radiant to watch the meteor shower.
But if the radiant isn’t in the sky, you won’t see many – if any – meteors. That means you should watch the Leonid shower tonight, from late evening (November 17) until dawn (November 18).
As a general rule, the higher the meteor shower radiant climbs into your sky, the more meteors that you’re likely to see. The radiant for the Leonids climbs highest up for the night during the dark hour before dawn, offering, perhaps, 10-15 meteors per hour. You should see at least a sprinkling meteors, if you watch for an hour or so.
What else can you see on the night of the 2015 Leonids peak? The radiant for the Leonids is near the star Algieba in Leo. This is not Leo the Lion’s brightest star. That distinction goes to Leo’s star Regulus. Watch for both of these stars. During the predawn/dawn hours, look for the line-up of planets in the eastern sky: Venus, Mars and Venus.
Both Algieba and Regulus belong to a noticeable pattern on the sky’s dome, in the shape of a backwards question mark. This pattern is called “the Sickle.” The paths of Leonid meteors can be traced backwards to the Sickle pattern, which is a famous asterism – or noticeable star pattern – within the constellation Leo.
By the way, the Leonids are a fast-moving meteor stream. The meteors impact the Earth at some 45 miles per second (72 km/second)! The Leonid meteor shower is known for having bright meteors or fireballs, which can punch into the atmosphere with the kinetic energy of a car hitting at 60 miles per second (nearly 100 km/second).
Bottom line: In 2015, the Leonid meteor shower is expected to be at its best on the night of November 17-18. Usually the most meteors fall in the dark hours before dawn.