On 9 May 2016 there was a transit of the planet Mercury across the Sun. This happens approximately 13 times per century, and always around 8 May or 10 November. The last visible transit of Mercury visible from the Netherlands was on 7 May 2003. The next time that the entire transit will be visible from the Netherlands will be on 7 May 2049. The first part of the transit of 11 November 2019 will visible from the Netherlands as well. After the Venus transit of 8 June 2004 this was my second observation of a transit of a planet across the Sun.
Members of our local astronomy society gathered a field close to my
hometown Assen. They brought a variety of telescopes. I took my 'old'
Canon 30D and a zoom + extender effectively giving me a 280mm lens.
This was just sufficient to picture Mercury as a little dot on the Sun.
The transit started at 13:12 local time and lasted 7 1/2 hours.
The little dot on the left is planet Mercury. The picture on the left is made at 13:33 local time, the picture at the right as 14:51. It show how much Mercury moves in 1 hour and 18 minutes. In the middle of the picture a Sun spot is visible. The apparent diameter of Mercury is about 1/160 of the apparent diameter of the Sun.
Bob brought an Astrophysics 130mm Starfire refractor with solar filter. Through this telescope Mercury appeared as a nice sphere before the Sun.
At the end of the afternoon I went home, and observed the transit with my Coronado PST solar telescope. With this telescope you can see the chomosphere of the Sun. The colour red is the hydrogen-alpha line with a wave lenght of 6563 ångström (656.3 nanometer). The chomosphere is the layer on the Sun just above the photosphere that we usually see.
With a compact camera I took a picture through the eyepiece of the PST telescope.
The diagram above shows the path of Mercury across the Sun. Due to the actual orientations of telescopes and camera, many pictures of the transit show Mercury at 'other' positions.