Saturn and Cassini’s Annual Pass Behind the Sun

This Solar & Heliospheric Observatory (SOHO) image, taken Sept. 18, 2009, shows a view of Saturn as it passes behind the sun, Cassini spacecraft in tow. Saturn Superior Conjunction is underway this week. This is when Saturn and the Cassini spacecraft are on the opposite side of the sun from Earth. During this time, which began on Sept. 15, Cassini’s high-gain antenna is pointed to Earth, called “Earth point,” and will continue this attitude through Sept. 20. During this time we don’t receive data like the raw images. New raw images will be downlinked Monday night and should be on the Cassini website on Tuesday Sept. 22.

In this view, Saturn is visible to the upper right of the white circle (the solar disk), which is blocked by a disk on the coronagraph instrument taking the image. The field of view in the image is 32 solar diameters — about 45 million kilometers (30 million miles), or nearly out to the orbit of Mercury. The streak accompanying Saturn is not the rings but a distortion caused by Saturn’s brightness.

Cassini Classroom Activity

“Monitoring the Sun’s Corona” is an inquiry based activity featuring Cassini Science and Engineering. Students learn how spacecraft use the relative positions of the Sun, Earth, and a spacecraft to study the Sun’s outer region, called the corona. See http://saturn.jpl.nasa.gov/education/EDUCATION58Program/edu58kitchen/ for a link to this activity and many more. Credit: SOHO – http://sohowww.nascom.nasa.gov