How to see Comet Leonard

Where did Comet Leonard come from?

As its name suggests, Comet Leonard was discovered in January of this year by Gregory Leonard, who spotted it in images taken from the Mt. Lemmon Observatory in Arizona. The discovery came about a year before the comet’s calculated perihelion — its closest approach to the Sun — which occurs next month on January 3. Right now, Comet Leonard is approaching Earth as it flies toward its rendezvous with the Sun, and it will make its closest pass to our planet December 12.

Leonard is a long-period comet, hailing from the outer regions of the solar system with an aphelion distance — its farthest point from the Sun — of some 3,700 astronomical units (AU), where 1 AU is the average Earth-Sun distance. Its orbital period is roughly 80,000 years. But that’s about to change: Calculations currently show the comet will be ejected from the solar system after it passes the Sun, destined to fly off through interstellar space, never to return. Perhaps it will even one day pass through another star system light-years away, just like the interstellar objects 1I/’Omuamua and 2I/Borisov recently passed through our own solar system. 

When and where to observe Comet Leonard

For the next few days, Comet Leonard is best seen in the early morning before sunrise. To find it, look east one to two hours before sunrise. It will climb highest in the sky right before dawn, but the sky will also be lightest at that time.

Below is a telescope finder chart that shows the path of fast-moving Comet Leonard in the morning sky until December 12. Note that it skims through several constellations in just a few days — if you take the time to watch the comet for an hour or so, you’re likely to notice it moving against the background stars in a single observing session. Before Leonard leaves the morning skies, it also poses nicely with several globular clusters: M12, M10, and M14.