Radiant point for Leonid meteor shower
Discuss Print Me Email to FriendTonight is Monday, Nov 16 2009
Don’t get too excited by looking at today’s chart. Yes, the famous Leonid meteor shower will peak tonight – actually, before dawn tomorrow according to U.S. clocks. But the waning gibbous moon will also be illuminating the sky at that time, drowning all but the brightest Leonids in its glare.
Our chart at left shows the radiant point in this annual shower – in the head of the constellation Leo. Meteors in annual showers stem from comets, and the radiant point is the point in the sky where we cross the comet’s orbit. It’s kind of like the point in the distance where train tracks converge.
The radiant for the Leonids is near the star Algieba. This is not Leo’s brightest star – that distinction goes to the star Regulus. 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.” In years when the moon is out of the way, the paths of Leonid meteors can be traced backwards to this Sickle pattern.
Leo rises in the wee hours after midnight in November, which explains why this meteor shower – like most annual meteor showers – is typically best after midnight. Can you see that you’ll observe more meteors when the radiant point is well above the horizon? Otherwise, some meteors are blocked by the body of Earth itself.
In good years for the Leonids, you don’t need to know how to recognize Leo to see the meteors. But we thought you’d enjoy knowing where the radiant is tonight, so you can imagine the meteors pouring from this point in the sky, drowned in the moon’s glare.
