ISS Transit of the Moon


ISS Transit of the Moon 04 May 2014.

It was a very low, less than 24 degrees transit and just about 3 degrees above the roof of the house. But it was my first chance in years to try my luck in imaging the ISS Lunar transit from my home observatory.


The seeing conditions weren’t quite perfect to say the least. Atmospheric turbulence effect is clearly evident in the animation:

The transit duration was just under 2 seconds, but the visible part duration was approximately 0.2 of a second. What is interesting about the result, is that I’ve done it, using two OTA’s and two cameras. EOS-550D was used to record the video through the 80mm f/6.25 Celestron refractor, mounted together with TAL-200K f/10 telescope, which was used for still frames with EOS-350D. The EOS-350D was not the best camera to use – some time ago I’ve removed the IR cut-off filter from it but it was the only option. The chances of having the ISS caught in one frame with the camera’s 3 frames per second and the visible pass duration of 0.2 of a second were quite good, but it was very dificult to find the ISS in one of the frames and, to my surprise, right in the middle of the visible part of the transit.

2014_05_04_iss_moon_transit-350DTime of the event: 17h55m41.9 s
Total transit duration: 1.97 s
Visible part transit duration: < 0.2 s
Distance to the ISS: 920.2 km
ISS angular diameter: 30″
Altitude: 23.7°

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