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Transit of Mercury Viewing Event – CONFIRMED ON

May 9, 2016 @ 12:00 pm - 6:00 pm

Transit of Mercury

THIS EVENT IS CONFIRMED ON. There is likely to be extensive cloud about, which may prevent us from seeing the transit, but we have decided to go ahead in the hope that the skies clear at some point.

On Monday 9th May, 2016, we will be running a special solar viewing session at the Royal Observatory Greenwich to view the transit of Mercury. The transit will be visible in its entirety from the UK (weather permitting!).

This session is open to all and is free of charge. There is no need to book, just turn up. We will be setting up at our usual location by the Altazimuth Building at the Royal Observatory. There will be at least 5 solar telescopes available for people to use. The session will start just after midday, when the transit begins.

A map of the location can be found here.

These are the timings of the transit from Greenwich:

  • Exterior ingress: 12:12:23 BST
  • Interior ingress: 12:15:35 BST
  • Maximum: 15:56:17 BST
  • Interior egress: 19:37:21 BST
  • Exterior egress: 19:40:33 BST

The duration of the transit is therefore nearly 7½ hours.

The Sun’s altitude at the start of the transit is nearly 55 degrees. At maximum, it is 41 degrees high, and at the end of the transit 7 degrees. Azimuth ranges from 161 degrees in the south to 289 degrees in the west.

Mercury will be just 12 arc-seconds across, meaning that the transit of Mercury won’t be visible without a telescope or other visual aid. Through a telescope it will be about the size of a medium-sized sunspot – gradually moving across the disc of the Sun.

From the Royal Observatory Greenwich, the sight lines mean that we may miss the last couple of hours of the transit. Therefore, we may de-camp to our usual location on Blackheath from about 5pm onwards, to view the end of the transit. This is obviously dependent on the weather and availability of our volunteers.


May 9, 2016
12:00 pm - 6:00 pm
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Royal Observatory Greenwich
Blackheath Avenue
London, SE10 8XJ United Kingdom
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