Transit of Mercury

There is no need to book for this event and there will be a reduced admission of just £6 per person.

The above image was taken by the NASA/ESA SOHO spacecraft which captured this image of Mercury transiting the Sun on Nov. 8, 2006. (Image: © ESA/NASA/SOHO)

While the transit does not start until 12.35pm The Centre opens as usual at 10am and closes at 5pm by which time the Sun will have set and it will be dark.

A rare transit of Mercury visible from the UK will occur on 11 November 2019. We will be joined by local astronomy societies and will be looking at the transit safely through specialist solar viewing equipment. There will also be a talk by Professor David Rees about why transits occur (see below).

What is a transit of Mercury?

Mercury is the closest planet to the Sun in our solar system.  Thirteen times each century the inner planet appears, from Earth, to cross the disc of the Sun. This is because it is passing directly between the Sun and Earth. This is known as a TRANSIT. It last happened on 9 May 2016 and will not happen again until 2032.

Mercury is very much smaller than the Sun and therefore only blocks out a very tiny part of the light coming from the Sun. Even if you were able to look at the Sun (which you must NEVER do) you would not be able to see the tiny black disc of the planet as it appears to move across the Sun, without the aid of a SOLAR Telescope. It’s extremely dangerous to look at the Sun, and even more dangerous to do so through an unprotected telescope

The tiny black disc of Mercury, just 10 arc seconds across, will take about five and a half hours to pass across the Sun. It will cross from east to west.

Mercury transits are rare because the innermost planet's orbit is inclined by about 7 degrees compared to that of Earth, so Mercury, the sun and our home planet just don't line up all that often.

Mercury completes one orbit of the Sun every 88 days, so the little planet crosses the plane of Earth's orbit every 44 days — once while moving "up" and again while coming back "down." These points of intersection are called nodes.

These nodes line up with the Sun from Earth's point of view just twice per year, once in May and once in November. If Mercury happens to be at the node at either of these times, Earth observers see a transit. (All Mercury transits occur within a few days of May 8 and Nov. 10.)

Transits of Mercury with respect to Earth are much more frequent than transits of Venus.

How to see the Mercury transit from the UK

Although it’s not a prime viewing spot, the transit of Mercury will be viewable from the UK. It will start at 12.35pm and will end at 6.04pm. However, the Sun will be setting at 4.15pm on the 11th November so we will not see all of it. The Sun will also be low in the sky so not ideal.

UK Mercury transit times:

12:35 – Mercury touches the Sun’s edge

15:19 – Mercury is nearest the Sun’s centre

16:15 – Sun sets with transit ongoing

Here at the Science Centre we will be observing the Sun safely through specialist equipment including a 90mm solar telescope. Come and join us and local amateur astronomers and enjoy this fabulous rare experience. Keep your fingers crossed for good weather though as we won’t see anything if the Sun is not out!

11.15am Talk by Professor David Rees: 'The Transit of Mercury'

Mercury will start to move across the face of the Sun around 12:30 pm and will continue to move across the Sun throughout the afternoon, eventually leaving the disc after sunset, as seen from the UK.

These planetary transit events only occur for Mercury and Venus. The events are very rare and the talk will explain why.

As ever, including solar eclipses, NEVER look directly at the Sun with any form of
binoculars or telescope to avoid very serious eye injury! However, weather permitting, the transit can be observed safely with a small telescope. This can be done by one of two methods:

1. Using a special solar filter mounted safely to a telescope to greatly reduce the Sun’s apparent brightness.
2. Using a small telescope to safely project an image of the sun onto a white screen.

The “Transit Method” is one of seven techniques used to discover exo-planets – those circling stars far beyond our solar system. These methods, and some of the intriguing information about exo-planets will be described. The next transit of Mercury will not take place until 13th November 2032. Don’t miss this one!!