New Delhi: Giving an almost once-in-a-lifetime opportunity to star gazers, Venus and the Sun are all set to present a rare celestial sight, scientifically called Venus transit, on June 8 when the planet will pass across the disc of the Sun.

"During the picturesque event, Venus would appear as a tiny black dot passing across the face of the Sun, in about six hours," Dr N Rathnasree, director of the Nehru Planetarium, said.

Venus would appear to travel from the Southeastern edge of the Sun to its Southwestern edge, she said.

However, it would be dangerous to look directly at the Sun. The safest method to view the transit would be to use simple field binoculars and project an image of the Sun, Rathnasree said. Besides, the planetarium is making arrangements for safe viewing of the event.

The event, to be visible from all over India, is like solar eclipse, but here Venus does not cover the face of the Sun and the sunlight is not blocked from reaching the Earth.

This is because the moon has nearly the same angular size as the Sun and thus covers the Sun entirely during a total solar eclipse but Venus disk appears as a tiny dot.

The Venus transit would also be visible from other Asian countries, Africa, and Europe. Eastern parts of US would be able to see the end of the transit, she said.

In India, the visible phase of the transit would begin at about 11 am and last till about 16:30 hours (IST).