The small and rocky planet Mercury is the closest planet to the Sun; it speeds around the Sun in a wildly elliptical orbit that takes it as close as 47 million km and as far as 70 million km from the Sun. Mercury completes a trip around the Sun every 88 days, speeding through space at nearly 50 km/s, faster than any other planet. Because it is so close to the Sun, temperatures on its surface can reach 467 degrees Celsius. Because the planet has hardly any atmosphere to keep it warm, nighttime temperatures can drop to -183 degrees Celsius. Because Mercury is so close to the Sun, it is hard to see from Earth except during twilight.

The Mercury transit of May 9th 2016

On May9th 2016 this celestial event took place and it was perfectly observable from the Netherlands. A Mercury transit is far less rare than a Venus transit. For my observation site the circumstances where perfect, starting at 56° altitude and ending at 4° altitude, I could see most of the transit from my backyard if weather permits. Apparent size of Mercury was only 12" in contradiction of the Sun's massive half degree apparent size.

Transit parameters for my home place (51°34'15" North, 5°28'15" East).

EventTimeAzimuth SunAltitude Sun
External ingress12:12 UT170.5°55.8°
Internal ingress12:15 UT171.8°55.9°
Maximum transit16:56 UT248.5°37.8°
Internal egress20:37 UT293.1°4.5°
External egress20:40 UT293.6°4.2°

At the start of the transit the first light cirrus clouds came in from the south-west and the seeing was bad.

All images made with an 300mm F/5 Newton with Thousand Oaks 90mm off-axis R-G Solar film, 0,73x ASA corrector and Canon 600D

Ingress in 6 steps

First 6 minutes of the transit in 20 seconds @ 450fps (9000 frames recorded @ 25fps)

Just after one hour of imaging more clouds rolled in and I had to use the few clear spots in the clouds for imaging. Just before maximum eclipse the clouds thicken and imaging was no longer possible

Transit at 13:30 local time (11:30 UT)

Transit at 13:57 local time (11:57 UT)

Transit at 16:12 local time (14:12 UT)
© Copyright Rob Kantelberg
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