The transit of Mercury – May 9, 2016

Sometimes objects fly in front of the Sun: bees, birds, planes, the International Space Station…and sometimes planets also.

Today it was Mercury that transited the Sun.

Not the best conditions for this imaging session, but I did manage to observe the event with my wife, Eli, from the Comana Woods, south of Bucharest.

For now, only a few shots are posted, since the 200Gb of data will take some time to analyze.

The image below, was acquired using the 115mm F/7 APO Refractor and 3x Barlow lens, full aperture Baader solar filter, ASI 174MM camera and a Baader Red filter. Seeing was 4/10, with a lot of clouds passing rapidly.

Eli did a time-lapse transit evolution with Mercury in different positions. Note the unequal distances between the positions since she captured the shots between the clouds:

And a short animation showing the great differences between white-light and H-alpha  in solar imaging:

Thanks to Adrian Sonka, I could use a Coronado PST (40mm) which “sees” only the light emitted by the Hydrogen atoms. It offered the best views while observing the event at the eyepiece.

A wide view with moderate resolution (for 13:42 U.T.):

A comparison of a Venus transit with a Mercury transit: the main image with sunspots is that of the Venus transit from 2012, onto which I’ve added my wife’s Mercury transit image from 2016, since only she acquired the full disc shots. Notice how small Mercury is compared to Venus while in transit…

Interestingly, there will actually be such a double transit in the future, in the year 60000 or so…in July 🙂