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Transit of Mercury

Photo - Transit of Mercury: Monday, May 9, 2016

This photo taken from Davis by Ted Swift, one of our Davis Astronomy Club members, at 11:32:52 during the Transit of Mercury on Monday May 9, 2016. 

The photo was taken at 11:32:52 PDT (UTC - 7) while Mercury was still well "inside" the sun.



  • The blurriness was a combination of the video camera's finite resolution, and heat ripples from atmospheric "seeing".
  • The numbers along the bottom of the frame are the exact GPS-synchronized Universal Time (UT, Greenwich Mean Time) of the video frame. 431 and 414 are the number of milliseconds corresponding to the end and middle times of the video frame. I.e., the middle of the video frame occurred at 18:32:52.414.
  • The number 29755 is simply the number of frames since the time inserter was last reset.


  • The Sun is approximately half a degree in diameter. According to the attached, Mercury's disk was about 12.1 arc-seconds (1/300 of a degree) across.
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