KATHMANDU: Skygazers in Nepal would be able to witness what scientists call 'a rare celestial event' as a hyperbolic comet, Comet C/ 2015 V2, would be approaching the Earth tonight.

Speaking to THT Online over the phone, Founder and Chairperson of Nepal Astronomical Society Suresh Bhattarai said, "The comet will be seen for once and all, posing a huge challenge for the scientists and astronomers all around the world to study its details and periphery."

"It is a golden opportunity to test scientific theories and analyse the comet, also known as Comet Johnson," according to Bhattarai. "The comet, which has risen at 3:04 pm as per the local time,  would be transiting at 9:43 pm and setting at 4:22 am tomorrow morning."

The comet will be at a distance of 121,339,786 km from Earth (0.811 astronomical units). The distance between Earth and Sun is considered one astronomical unit.

For this comet to be seen, Boötes constellation has to rise as it is currently at this constellation. The Comet Johnson is in the mid-latitude northern-hemisphere, on the side of eight stars currently at around apparent magnitude of 9, stated Bhattarai.

The apparent magnitude of a celestial object is a number that measures its brightness as seen by an observer on Earth.

"The comet can be observed with the help of a telescope or a pair of binoculars. We have been following it since May. When discovered, it was of 17+ magnitude", he added.

Except for the weather, the moonlight might also play a spoilsport causing the comet to appear dim, he claimed.

Meanwhile, the Nepal Astronomical Society is organising a special free event for the skygazers to observe the rare celestial event at Gaushala-based Ankur Vidhyashram from 6:30 pm to 9:00 pm tonight.

The visitors would also get a chance to observe the Moon, and Jupiter and its four moons in the programme this evening.