Expanding solar clouds (July 24, 2009)
The HI-1 instrument on STEREO (Ahead) observed as barely visible streams and occasional clouds of solar particles head away from the Sun. The video clip suggests a generally quiet level of solar activity, with a steady streaming of solar particles and three faint clouds that are expanding as they cross the field of view (July 11-18, 2009). The sources of those clouds most likely are small solar storms. The HI-1 instruments on each of the two STEREO spacecraft are wide-angle visible-light imagers that can detect the passage of solar coronal mass ejections (CMEs) through the heliosphere. Each HI instrument has a 20¡ field of view and is off-pointed from the Sun direction by 14.0¡. These are one pair of NASA's space weather watchdogs.
SOHO began its Weekly Pick some time after sending a weekly image or video clip to the American Museum of Natural History (Rose Center) in New York City. There, the SOHO Weekly Pick is displayed with some annotations on a large plasma display.
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