Images of the transit of Mercury in front of the Sun. Click on the images for larger versions. Visible are Mercury (upper left region of the solar disc), a large sunspot (lower right in most images, at the centre of the solar disc in the image of the full solar disc), and a group of sunspots (on the right-hand limb in the full solar disc image).
The transit was viewed by students at the University of Exeter
Observatory by projecting the solar image on to a screen and taking photos
with a digital camera. This is a
safe method for observing solar phenomena, since viewing the Sun
directly using the naked eye, or an optical instrument such as
binoculars, may lead to permanent blindness.
Note the motion of Mercury relative to the large sunspot over the 1 hour, 40 minutes spanned by the photos. We did not obtain images of Mercury very near the edge of the solar disc due to cloudy weather.
Transits of the planet Mercury are a relatively rare occurence, with on average thirteen transits per century. Mercury appears as a small black disc that passed across the face of the Sun. The planet, which has a diameter of 5000 kilometres, is dwarfed by the Sun, which is a collosal 1.4 million kilometres across.