Calcuttans willing to walk the extra mile can watch the spectacle of meteor showers on successive nights starting Friday, thanks to a stream of dusty debris left by Halley’s Comet.

One can expect to see 20 to 25 shooting stars per hour, but to observe them one has to go beyond city limits where light pollution is the least, said Debiprosad Duari, the director (research and academic) of MP Birla planetarium.

A waning moon may affect the viewing but if one watches between midnight and dawn one could see some meteors, said Duari.

The meteor shower appears to be originating from the constellation of Orion and hence it has been named the Orionid.

The “meteoroids” that are part of the shower are usually no bigger than grains of sand and much less dense. However, these debris particles make brilliant shooting stars when they strike the earth’s atmosphere, generally at a speed of 66km per second and burn up typically 100km above the earth’s surface.

The last time Halley’s Comet came closer to earth was in 1986. It will again come near earth in 2061. Each time it swings by the sun, solar heating evaporates about six metres of ice and rock from its nucleus.

Although the comet is now at a great distance in the outer periphery of our solar system, it left behind a stream of dust through which the earth passes twice a year in May and October. May brings the Eta Aquarid meteor shower and October the Orionid.