How to See the Giant Asteroid That Will Pass by Earth This Weekend

The European Space Agency (ESA) confirmed that this weekend, asteroid (152637) 1997 NC1 will make its closest approach to Earth in 400 years. There’s no risk it will hit Earth, but it will be visible through commercial telescopes and astronomical binoculars from various parts of the world.

The closest approach will occur on Saturday, June 27, when the asteroid will pass 2.56 million kilometers (1.59 million miles) from Earth—a distance equivalent to 6.6 times the distance between Earth and the moon. The object—with a diameter estimated to be between 700 meters and 1.6 kilometers—will not come this close again until 2133, according to the ESA.

When Will the Asteroid Be Visible?

The asteroid will be closest to the Earth on Saturday, June 27 at 11:14 UTC. The best time to view it will depend on your location, though. Here’s a rough breakdown for various regions:

• Europe: the night of June 26 to 27, especially in the early morning
• Mexico: the night of June 26 to 27
• The US: the night of June 26 to 27, with the best viewing conditions before sunrise
• Argentina and the Southern Cone: the night of June 27 to 28, once the asteroid has moved toward the southern sky

The asteroid will not disappear immediately after its closest approach. It will remain visible for several days, although its brightness will gradually decrease and its position in the sky will shift. If you’re unable to observe it on the first night, you’ll still have opportunities in the following days, although conditions will be less favorable for those in the northern hemisphere.

What Will the Asteroid Look Like?

Despite being bigger than a skyscraper, the asteroid will be impossible to see with the naked eye. The ESA estimates that it will reach a brightness close to magnitude 10, similar to that of Neptune.

Through a telescope or astronomical binoculars, the asteroid will appear as a small point of light moving slowly among the stars. Its movement will be approximately 40 arc seconds per minute. It’s a somewhat obscure astronomical measure of movement, but suffice to say that it will be enough to notice the object moving if you watch it for a few minutes.

What Equipment Do You Need?

You’re going to need more than your eyes. Even under the clearest night sky, the asteroid is 40 times fainter than the faintest stars the human eye can distinguish. The moon is also near full, which will reduce the contrast in the sky and make it harder to observe other objects in the night sky.

At the moment of closest approach, it will be near the constellations Ophiuchus and Serpens Cauda, south of the bright star Vega. Astronomy apps such as Stellarium, Sky Tonight, or SkySafari, can help you locate where it is in the heavens at any given time by searching for “1997 NC1.”

For more than an apps-eye view, astronomers recommend using a commercial telescope with an aperture of at least 100 millimeters (4 inches), although models ranging from 150 to 200 millimeters will provide a much more comfortable viewing experience. It will also be possible to spot it with 15 x 70 or 20 x 80 astronomical binoculars, preferably mounted on a tripod and from a location away from light pollution.

If it’s cloudy or you don’t have a telescope handy (or you just prefer watching celestial events from your couch), the Virtual Telescope Project is hosting livestreams on June 26 and June 27 that will track the asteroid.

This story originally appeared on WIRED en Español and has been translated from Spanish.