Observing the Mercury Transit - never mind the clouds

Observations of the Mercury transit by SWAP.

Predicted timings and configuration of the Mercury transit as seen by SWAP.

Subfield observations made by SWAP.

Here we show images of the Mercury transit as seen in EUV by the SWAP telescope onboard ESA's PROBA2 satellite. Observing at 1 million degrees, SWAP does not see the solar surface but the hot outer solar atmosphere called the corona. It is difficult to spot Mercury in these images because this small planet will only cover just about 4 pixels in our 1024 x 1024 pixels field-of-view. Mercury can most easily be found when it travels over bright patches in the solar atmosphere.

The simulation on the right shows you what the SWAP movie will look like. Mercury is a tiny circle that follows a wobbly path due to the orbit of the observing spacecraft around the Earth.

SWAP images will be added here as soon as they are available. Due to PROBA2's orbit, images are stored onboard and downloaded approximately every 4 hours when the spacecraft passes over one of our two ground stations (one situated in the Arctic and the other in Belgium). The most recent images can be downloaded from the PROBA2 Science Centre website. Note that before the Mercury transit a placeholder movie of the 2012 Venus transit is shown.

PROBA2 carries another instrument: LYRA, a radiometer measuring the solar irradiance. Due to the fact that Mercury will only cover a very small part of the solar surface, it will not block much of the solar radiation. We therefore do not expect the to see any variation above the noise level in the signal detected by LYRA, except maybe at the times when Mercury crosses the solar limb.

Mercury in FOV of SWAP on 9 May 2016 Mercury transiting the Sun, SWAP FOV
08:14:49UT till 21:47:41UT 11:13:56UT till 18:42:10UT
More information about PROBA2 transit coverage is available HERE . Please credit PROBA2 images and movies as ESA/ROB.

Remark : Belgian Local Time (LT) = Universal Time (UT) + 2 hours