Date: 9 May 2016
Equipment: Starlight Xpress SXV-H9, Vixen ED 114mm aperture f5.3 refractor, through an Astronomix H-alpha filter and Baader solar film
Subframes: 12 x 0.005s, stacked and sharpened in Registax 2.1.14
Images were taken in between clouds at approximately 15 minute intervals until they finally rolled in completely.
The break in the sequence of Mercury images was down to cloud cover. Two sunspot clusters are visible above the tiny dots of the planet's trail. As the images were aligned on the Sun's disc, the Sun's rotation has spread out their appearances.
Below is a single image, taken at 12.15 at "second contact" (where Mercury's trailing edge comes on to the Sun's disc). It shows the active areas 2542 and 2543 in sharper focus, unaffected by the Sun's rotation.
The next transit of Mercury visible from the UK will be on 11 November 2019, with first contact at 12.35. They occur either in May or November every few years, at well-defined intervals.
They are much commoner than transits of our other "inferior" planet, Venus, an event which will not be seen in its entirety from the UK until 11 June 2247. I was fortunate enough to be able to capture the last UK-visible Venus transit event back in June 2004 (images here).
