ISS Transit of the Moon

October 23, 2023

Sat-trans-20230901 (1)

Photographer: Anthony Ayiomamitis  
Summary Author: Anthony Ayiomamitis   

It’s quite difficult to have a chance transit of the International Space Station (ISS) against the Sun or Moon since these two celestial neighbors each cover an area of only 0.25 square degrees of the sky. So, one needs a fair amount of luck to catch the ISS transiting either one of them. Equally challenging is the impact of the weather – not only clear skies but good seeing conditions, with respect to the transparency of the sky, lack of winds etc., are a must to observe such a crossing.

A few weeks back, I was able to catch the ISS transiting the Moon when it was about one day past full. At the time the ISS was at a distance of 359 miles (577.1 km) and moving in a southwestern to northeastern direction (bottom right to upper left. The transit lasted a brief 0.71 seconds. Please note that the middle capture involves the ISS immediately over the Lunar Apennine Mountain region and the landing area of the Apollo 15 mission (July 26 - August 7, 1971).

Photo details: Due to a high angular velocity (40.9 ' / sec), an exposure of 1/4000th second exposure was required to "freeze" the moving ISS. My camera was in servo mode (ie continuous shooting mode at 4.7 fps).

Athens, Greece Coordinates: 37.9838, 23.7275

Related Links:

Transit of the Sun by the International Space Station and Cicadas

Further details in relation to this result are available on my website