Moving at eight kilometers (five miles) per second, the International Space Station (ISS) surrounds our planet every 90 minutes. In a 24-hour period, crew members on the ISS experience 16 sunrises and sunsets. Despite the frequency with which the station passes directly between Earth and the Sun, it is rare to capture an image of the ISS transiting our nearest star.
On June 24, 2020, POT Photographer Joel Kowsky captured this fact in Fredericksburg, Virginia. The image above is a composite, made of six squares, and shows the ISS in silhouette as it moved from right to left through the solar disk while orbiting 400 kilometers (250 miles) above Earth.
The image below shows the position of the ISS in its orbit when Kowsky took his photos at approximately 1:15 p.m. Eastern Time. The transit lasted approximately 0.54 seconds and was captured while his camera was shooting at 10 frames per second. Watch a video of the transit below.
Ten photos assembled in sequence show the International Space Station, with a crew of five on board, silhouetted as the Sun transits at approximately five miles per second, Wednesday, June 24, 2020, from Fredericksburg, Virginia. On board are NASA Expedition 63 astronauts Chris Cassidy, Douglas Hurley, Robert Behnken and Roscosmos cosmonauts Anatoly Ivanishin and Ivan Vagner. Photo credit: (NASA / Joel Kowsky) Note: The sequence repeats three times.
Kowsky says many websites help identify when the ISS will transit the Sun, but weather and weather are often the main problems with taking clear photos. “With a very limited visibility path along the ground, having a clear climate at the identified location is one of the most limiting factors in capturing traffic,” said Kowsky, who caused the weather to ruin a recent attempt. Proper safety equipment is also necessary when photographing the Sun, as looking directly at it can harm your eyes.
NASA has previously released images of the ISS crossing the Sun, including during the total solar eclipse in August 2017. Recent transit images (such as the one shown below) have also shown a lack of sunspots as the Sun enters a period of low solar activity known as the solar minimum.
Photograph by NASA / Joel Kowsky. Map of the Earth Observatory by Joshua Stevens.