1. What, when, where
The innermost planet, Mercury will pass in front of the Sun on Monday, 9th May, 2016. This solar transit will start at 12:12 BST and end at 19:42 BST.
If the skies are clear, the transit will be visible from most of Western Europe, South America and Eastern North America. The transit of Mercury is a rare event and this year it will be the first since November, 2006 and only the thirtieth since the foundation of the Royal Philosophical Society of Glasgow on 9th November, 1802. The latter event is commemorated in the Society logo.
The next transit will be on 11th November, 2019. After that there is a long wait until 2032
2. Viewing the Transit
The transits of Mercury are not visible to the unaided eye: the angular size of Mercury is about 12 seconds of arc corresponding to about 1/150 th of the diameter of the Sun.
A magnified image (30X to 100X) is required to see the black dot of Mercury against the disk of the Sun.
If you plan on watching the Transit of Mercury
IT IS VITAL TO TAKE SOME BASIC STEPS TO PROTECT YOUR SIGHT.
TO AVOID PERMANENT DAMAGE TO YOUR EYESIGHT DO NOT ATTEMPT TO LOOK AT THE SUN.
A RELATIVELY SAFE WAY is to project the Sun’s magnified image through a telescope on to a white card or screen. This is also useful for group viewing
Inexpensive reputable solar projectors are available suitable for group viewing and photography. An example is mentioned by the British Astronomical Society:
The Solar Projector (Klaus Hunig- Astromedia): a 275 g strong cardboard kit including a f=250 mm achromatic lens, and two convex mirrors with f= -10.2 mm, f= -14 mm. It is easily assembled. The result is a camera obscura sett up with a Dobsonian mount. It should show Mercury as a 0.5 mm dot on a 7.5 cm projected solar image. The Solar Projector costs about £20 and is available from
http://www.amazon.co.uk (astromedia – the solar projector) and
http://www.astromediashop.co.uk/Astronomy.html
3. What to expect
3.1 A YouTube video of a simulation of what happens.
3.2 A heavily filtered time-lapse photograph of the 2006 transit (ESA).
4. Live Streaming
The safest way to view the transit is via live streaming.
The European Space Agency has details here.
5. BepiColombo: the European Space Agency (ESA) mission to Mercury, July 2016
BepiColombo is Europe’s first mission to Mercury. It will launch in July 2016 on a journey to the smallest and least explored terrestrial planet in our Solar System.
Arriving at Mercury in January 2023, it will endure temperatures in excess of 350°C and gather data during a 1 year nominal mission. The mission comprises two spacecraft: the Mercury Planetary Orbiter and the Mercury Magnetospheric Orbiter.
6. References
1. 46th Lunar and Planetary Science Conference (2015) 1327
2. Transit of Mercury BAA report
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John Barker, March 2016
Many thanks to John Brown (Astronomer Royal for Scotland) and Jeffrey Jay for helpful details.
