Currently, the transits of Mercury take place in May (near its passage through the descending node) or in November (near its passage through the ascending node), the latter being more frequent because Mercury is closer to the Sun when it passes through the ascending node and this favours the geometry of perfect alignment.
Another characteristic of the November transits is that they last less, about 5 hours as opposed to almost 8 eight hours in May, due to the fact that as the planet is closer to its perihelion (closest point of its orbit) Mercury moves faster (remember Kepler's second law).
I had the opportunity to photograph the previous one of May 9, 2016, and this last one of November 2019, both very elusive due to the weather conditions, but which offered some moments of visibility in which the clouds, although present, were not so dense as not to allow the Mercury backlighting to be seen.
Some moments were photographed which allowed the projection of Mercury's trajectory and which, superimposed, give rise to the photo shown below.
The photographs were taken with an ASI1600mm Pro camera with a sun filter on the telescope (C8 on EQ6 mount) and an infrared filter (Astronomik ProPlanet 742 IR) on the camera. The exposure time varied between 0.01s and 0.1s depending on the density of the clouds. The color was added with Photoshop. The next visible transit from Majadahonda will be in May 2049. Here we will wait for it... if everything goes well.
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