No, this is not a TIE fighter gong over the sun, it is the International Space Station. And while getting a shot of the ISS over the sun is competently doable, getting that shot with Mercury in the frame is an epic effort. Engineer and photographer Thierry Legault took this composite of the ISS, Sun and Mercury at a carefully selected location and date in Philadelphia, USA. You see during the entire 21st century there are only 14 times that Mercury goes over the sun. Add to that the precision needed to capture the exact 0.6 seconds of ISS transit and you can start understating how hard it can be.
The video was taken with: Takahashi FSQ-106ED refractor at f/10, a Coronado SM90 H-alpha filter and an IDS UI-3370 4 MP video camera (yes 4mp). Definitely not your standard set of gear. And just to reaffirm, here is a closer look at the moving object, definitely the ISS and not a TIE fighter:
If you look at the second part of the video, you can see another double transit: a plane – a Pilatus PC12 aircraft – going over the sun, interestingly, it seems as the propeller is not really moving. interestingly, it seems as the propeller rotation speed is almost in full resonance with the camera frame rate. A closer look though reveals a slight phase between the two:
A note about (apparent) size:
It would seem that Mercury is the smallest of objects, followed by the ISS and that the Pilatus PC12 aircraft is the largest. This, of course has to do with the different distances of those objects from earth. The ISS is about 450 kilometers from Philadelphia; Mercury was about 84 million kilometers away; and the Pilatus PC12 was only about 1 kilometer away. This serves as a great illustration on how distance effects size. [Thierry Legault via APOD]
