It’s asteroid Nereus day: how to observe it from Earth

Asteroid 4660 Nereus will pass less than 4 million kilometers from Earth. Thanks to the National Institute of Astrophysics, we know how to observe it from Earth.

Today is the big day: asteroid 4660 Nereus will pass within 4 million kilometers of Earth. The celestial body is not a threat to our planet, and indeed is the focus of scientists' interests for several reasons.

Big as the Eiffel Tower

Nereus is the famous asteroid "as big as the Eiffel Tower" estimated to be worth billions of dollars as it is rich in rare metals, which is reported to be approaching the Earth for a few months now. It is in fact an asteroid that has been monitored for almost twenty years now: we know its orbit, its shape, its size and we know that it reflects much more light than other asteroids.

Nereus fascinates scientists especially because its delta-V with respect to Earth is very low, which means that any approach to the celestial body during a mission would require less effort, in maneuvering, than in other cases. Nereus was in fact one of the asteroids in contention for the NEAR (Near-Earth Asteroid Rendezvous) mission, which instead ended up on the asteroid Eros, and also for the Japanese mission Hayabusa, then diverted to Itokawa.

The flyby with the Earth is scheduled for today at 13.51: at that time Nereus will pass 3.9 million kilometers from our planet.

Come osservare Nereus dalla Terra

L’asteroide 4660 Nereus riflette molta luce solare, ma si troverà comunque ad una distanza che è circa 10 volte quella che separa la Terra e la Luna, nel momento di massima vicinanza con il nostro pianeta.
Non sarà visibile ad occhio nudo, come riportato dall’Istituto Nazionale di Astrofisica, ma chi volesse tentare di intercettare l’asteroide near-Earth potrà farlo seguendo alcuni accorgimenti.

Nereus “raggiungerà la magnitudine apparente di +12,7”: nella scala che indica la visibilità ad occhio nudo dalla Terra, solo i corpi celesti con magnitudine apparente inferiore a 7 sono visibili senza strumentazioni dalla Terra.

Per poter intercettare Nereus, continua l’Inaf, è sufficiente un telescopio di 15 centimetri di diametro. Weather permitting, then, you can try to photograph the asteroid with telephoto lenses "from 135-200 mm focal length with guided poses" of at least three minutes.

Nereus will be visible by pointing the instruments towards the constellation of Ursa Major: in the morning it will be about one degree from the star Dubhe, the second star of the constellation, which can be taken as an easy reference point, while during the evening it will move slowly towards the center of the Big Dipper.