Twilight sky at Gusev crater

Pointing its cameras skyward, Spirit captured the Martian twilight sky at Gusev crater with the panoramic camera around 6:20 in the evening of the rover's 464th Martian day, April 23, 2005.

The beauty of the twilight is also scientifically useful, allowing the research team to determine how high into the atmosphere the Martian dust extends, and to look for dust or ice clouds.