One Blue Week (July 28, 2006)
Hi-res TIF image
For one full week (July 20 -- 26, 2006), SOHO observed the Sun in this extreme ultraviolet light (171 Angstroms) at a high frame rate, something it has only done a few times over its 10-year run of solar observing. The ensuing movie consists of images taken every 12 minutes and run together at 24 frames per second, so the motion is speeded up considerably. At this wavelength, one is actually seeing ionized particles of iron heated to about 1.5 million degrees in the lower corona of the Sun. The blue is just a false color added to the original black and white image to make it clear which instrument took this series. The whiter areas are active regions, which would correspond to dark sunspots if one were observing the Sun with a telescope and a solar filter. The most interesting event of the week was the eruption of a prominence associated with a coronal mass ejection on July 20 around 15:00, which is followed by a series of post coronal loops that look like a slinky in the lower left quadrant. For the most part, the Sun was generally quiet as befits a Sun nearing the most quiet period in its 11-year solar cycle.
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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