SACRAMENTO — Last week, the northern lights people across Northern California looked up at the night sky. Now another rare celestial event is on the horizon.

Look closely. Can you see it? That bright spot with a green glow in the night sky is a comet hurtling past Earth – but don’t worry, it’s still over 45 million miles away.

Raj Dixit of the Sacramento Valley Astronomical Society said Comet Tsuchinshan-ATLAS was first discovered last year. Astronomers say it came from the far reaches of our solar system.

“How often do you get to see something that’s three light years away, 20 trillion miles away, and that’s older than planet Earth itself?” said Dixit.

It’s been visible in the Southern Hemisphere for weeks, and now people are seeing it across Northern California.

“It’s getting higher every day this week and will get higher in the sky every day until the end of October,” Dixit said. “The problem is that it’s getting weaker and weaker as it moves further away.”

It is best visible through a telescope, binoculars or telephoto lens, but it can also be seen with the naked eye. To see it, look southwest after sunset near the plant Venus.

“It sets in the evening, so you don’t get that window until after sunset,” Dixit said. “So thinking ‘after midnight it gets really dark’, no, that’s not going to work. It will be gone by then.”

The comet’s tail is formed by light reflecting off ice and rocks shed as it flies past the sun.

“This comet actually had two tails at certain points – a leading tail and a trailing tail,” Dixit said.

NASA says the best chance to see it is now through October 24, and if you don’t see it this year, you’ll have to wait a while because it won’t be visible for another 80,000 years.