Prominence Comparison (February 24, 2006)
Hi-res TIF image (685K)
SOHO observed this modest prominence in extreme ultraviolet light on February 15, 2006. Unbeknownst to us, Greg Piepol, amateur astronomer and solar observer, was capturing this same prominence in Rockville, Maryland sometime on that same day. When his image appeared the next day on the Spaceweather.com site, we realized that it was the same prominence that we had seen.
So, for one thing, it shows what can be done with a nice telescope with a Hydrogen-Alpha filter (which is admirably suited for spotting such prominences) and a digital camera. And for another it suggests that these two wavelengths are observing similar phenomena. The material in prominences is constantly being refreshed by heating in the otherwise cooler atmosphere below and that that "hotter" material flows through magnetic structures in the otherwise much hotter (but much less dense) corona. While individual (quiescent) prominences can last for weeks, the material at any point in the structure is constantly in motion. They can last from hours to weeks. This one was mostly gone two days later.
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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