IN PICTURES: Transit of Mercury
As Lancashire basked in May sunshine, the cloudless skies gave astronomer Len Adam the rare opportunity to photograph the planet Mercury as it made its way across the sun for the first time in a decade.
It was a little black dot with great significance.
A Lancashire astronomer captured the rare Transit of Mercury as the planet made its way across the face of the sun for the first time since 2006.
Len Adam, from Leyland, took advantage of the rare cloudless skies on Monday to take a series of images as Mercury appeared in an event which only happens around 14 times a century.
The planet, which is almost 5,000km (3,032 miles) in diameter, appeared as a tiny black dot and was impossible to see with the human eye.
Even though it looked as though the planet crawled across the surface, Mercury actually moves at a speed of 50km (31 miles) per second.
Mr Adam photographed the planetary transit from back gardens in Walton-le-Dale and Leyland using a 90mm diameter telescope and a commercial solar filter using Mylar film, together with his Canon 40D digital SLR camera.
The assembly was mounted on a Skywatcher Star Adventurer mount set to track the sun across the sky with the camera set to 1/125 of a second exposure.
His images show the small dot making its way from the left to the right of the sun.
The other visible dot on the image is a cluster of sunspots, not visible to the naked eye.
He said the transit started shortly after 12 noon and he first saw Mercury through his DSLR camera viewfinder attached to a his smaller telescope.
He said: “The transit was to take all day and fortunately it remained clear in Lancashire unlike Cornwall, where a fellow astronomer reported to me that it was completely overcast.
“Image T2 was taken at 12:17 and Mercury had now moved clear of the edge of the s un to appear as a small dot.
“By 12.30 the dot was a little clearer and illustrated just how small the planet Mercury is when compared to the Sun.
“By 19:36 Mercury was almost invisible in my little telescope.”
The event was also been live-streamed online by the European Space Agency which pointed its Great Equatorial Telescope, the largest lensed in the UK at 28 inches, towards the sun for the first time since 1927 and used a special solar filter for the viewing during an eight-hour window from midday.
Public Astronomer Dr Marek Kukula said it was an “exciting” occurrence.
He said: “The last one was in 2006. These events don’t happen every day, so it’s a lovely chance to see it.
“Events like this are important for two reasons - historically they have helped astronomers work out how big the universe was, and now they are used to detect solar systems outside our own and help us understand the scope of the universe.”