APOD
Astronomy Picture of the Day
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
International Space Station Crosses the Sun
Explanation: Typically, the International Space Station is visible only at night. Slowly drifting across the night sky as it orbits the Earth, the International Space Station (ISS) can be seen as a bright spot about once a month from many locations. The ISS is then visible only just after sunset or just before sunrise because it shines by reflected sunlight -- once the ISS enters the Earth's shadow , it will drop out of sight . The only occasion when the ISS is visible during the day is when it passes right in front of the Sun . Then, it passes so quickly that only cameras taking short exposures can visually freeze the ISS's silhouette onto the background Sun . The featured picture did exactly that -- it is actually a series of images taken a month ago from Sant Feliu de Buixalleu , Spain with perfect timing. This image series was later combined with a separate image highlighting the texture of the active Sun which included several Sun's prominences around the edge.
Celestial Surprise: What picture did APOD feature on your birthday? (post 1995)
| Date | May 21, 2025 |
|---|---|
| Credit | Image Credit & Copyright: Pau Montplet Sanz |
| Authors & editors: | Robert Nemiroff (MTU) & Jerry Bonnell (UMCP) |
| A service of: |
ASD at NASA / GSFC, NASA Science Activation & Michigan Tech. U. |



