European Space The Agency (ESA) has confirmed that this weekend, the asteroid (152637) 1997 NC1 will be closest to Earth in 400 years. There is no risk that it will reach Earth, but it will be visible through commercial telescopes and astronomical televisions from various parts of the world.
The closest approach will be on Saturday, June 27, when the sky will pass 2.56 million kilometers (1.59 million miles) from Earth—a distance equal to 6.6 times the distance between Earth and the moon. The object — with an estimated diameter of between 700 meters and 1.6 kilometers — will not approach again until 2133, according to the ESA.
When Will an Asteroid Be Visible?
The asteroid will be closest to Earth on Saturday, June 27 at 11:14 UTC. The best time to watch it will depend on your location, though. Here is a rough breakdown of the various states:
- In Europe: the night of June 26 to 27, especially in the early morning
- Mexico: the night of June 26 to 27
- US: the night of June 26 to 27, with the best viewing conditions before sunrise
- Argentina and the Southern Cone: on the night of June 27 to 28, when the asteroid has moved towards the southern sky.
An asteroid will not disappear immediately after its approach. It will remain visible for several days, although its brightness will gradually decrease and its position in the sky will change. If you can’t see it on the first night, you’ll still have chances in the following days, although conditions will be much better for those in the northern hemisphere.
What Will an Asteroid Look Like?
Despite being larger than a skyscraper, the asteroid cannot be seen with the naked eye. ESA estimates that it will reach a brightness close to magnitude 10, similar to that of Neptune.
With a telescope or astronomical binoculars, the asteroid will appear as a small point of light moving slowly between the stars. Its motion will be about 40 arc seconds per minute. It is a somewhat vague measure of the motion of the stars, but suffice it to say that it will be enough to notice a moving object if you observe it for a few minutes.
What Items Do You Need?
You will need more than meets the eye. Even under the clearest night sky, the sky is 40 times fainter than the smallest stars that the human eye can distinguish. The moon is also close to full, which will reduce contrast in the sky and make it difficult to see other objects in the night sky.
At its closest, it will be near the constellations Ophiuchus and Serpens Cauda, which are south of the bright star Vega. Astronomy apps like Stellarium, Sky Tonight, or SkySafari, can help you find where it is in the heavens at any time by searching for “1997 NC1.”
For more than just observing applications, astronomers recommend using a commercial telescope with an aperture of at least 100 millimeters (4 inches), although models from 150 to 200 millimeters will provide a comfortable viewing experience. It will also be possible to see it with 15 x 70 or 20 x 80 astronomical telescopes, preferably placed on a tripod and away from light pollution.
If it’s cloudy or you don’t have a telescope handy (or you prefer to watch celestial events from your couch), the Virtual Telescope Project is hosting live broadcasts on June 26 and June 27 that will track the asteroid.
This story appeared first WIRED in Español and translated from Spanish.
