Durban - Local astronomers are gearing up for a big solar event this week as Mercury - the innermost planet of our solar system - will transit the sun on Monday November 11. 

Claire Odhav of the Astronomical Society of Southern Africa, Durban chapter, said "Mercury will pass directly in front of the sun and be visible through telescopes with solar filter as a small black dot crossing the sun's face.

"The transit or passage of a planet across the face of the Sun is a relatively rare occurrence to view. While planets transit the Sun regularly, the orbits of the planets are slightly tilted, relative to each other, so things line up just right only occasionally," she said.

The transit begins with Contact 1, which is the instant when the planet's disk is externally tangent to the Sun. In Durban, the first contact is at 14:35:27 and will last till after sunset. "So we will have a good view of it until about 6pm," said Odhav. "And this is not a regular event, so don't miss out."

The viewing afternoon will take place at the Pavilion room at St Henry's Marist College in Glenwood. "The balcony faces west, so we should have a good view from there, weather permitting, so please join us," said Odhav. "If you have a solar scope or filter, do bring it along. Members and visitors are welcome."

The last transit was in 2016, while next transit of Mercury is only in 2032.

Odhav advised people never to look at the sun directly or through a telescope without the correct filters. 

The Independent on Saturday