Mercury photographed in evening sky

Mercury in the night sky at Horndean, Picture: Steve Bosley
Mercury in the night sky at Horndean, Picture: Steve Bosley
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It might appear as little more than a pin prick in the evening gloom, but this is the planet Mercury clearly visible in the skies above Portsmouth.

The image is one of a series taken on January 18 by Steve Bosley of the Hampshire Astronomical Group based at the Clanfield Observatory.

Steve, who captured the shot near his home in Horndean, said: ‘Sunset was at 16:31 and so I watched out from around 16:45, first with binoculars, but then naked eye.

‘In truth Mercury was a very hard spot but I was guided by Venus which appeared first down in the south west, and which, at apparent magnitude -3.4, was around 23 times brighter than magnitude 0.06 Mercury.

‘I eventually found Mercury about 3 degrees west of Venus (about 6.5 Moon diameters) when they were both about 10 degrees above the horizon.

‘My photos were taken with a Canon EOS70D camera with a 28-135mm lens set at 100mm with aperture f/7.1 and ISO 800 and manually focussed.;

The exposure for the image displayed here was 0.3 seconds.

Stagazers in the Portsmouth area have a rare chance to see Mercury in the night sky during January.

Mercury revolves around the Sun in an elliptical orbit with a period of just 88 days and at an average distance from the Sun of approximately 58 million kilometres.

Because this is much less than the average distance of Earth from the Sun, Mercury never strays far from the Sun in the sky.

It is always difficult to find in the morning or evening twilight, even when at its greatest angular distance from the Sun.

This year, however, Mercury occupies the same patch of sky, in nearly exactly the same direction, as its much brighter neighbour Venus.

The brighter planet, which is easily visible to the unaided eye given clear skies, is a celestial signpost to help find the elusive and much fainter Mercury.

Such close alignments of these two inner planets on the sky are quite rare, occurring on average just once every five years or so.