- The Chicago Astronomer -
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Last Saturday Adler volunteer Ron Rotunno and I had a tremendous afternoon of solar observations. The sights were simply astounding. Although the white light filter on the 8" dob showed no sunspot activity, the H-alpha scope showed solar prominences everywhere -- at least eight distinct regions at around 2:30 p.m. High loops, wide loops, tall fountains, some of them extremely bright, others with countless fine filaments. Adler Master Educator Michelle Nichols stopped by and said it was the best she has seen in 11 years! We joked that this was the Sun's "one-ups-manship" on Buckingham Fountain which mayor Daley had just turned on for the season earlier that same morning. I consider myself very fortunate to have had a day like that. Ron was kicking himself for not bringing along his imaging equipment.
P.S. -- How do I distinguish a solar flare from a solar prominence?
Post by Chicago Astronomer Joe on Apr 27, 2006 13:58:39 GMT -6
I haven't had a good solar session in quite awhile. Considering how dead the Sun has been recently and I am pleased you experienced great one. I'll be there for Astronomy Day doing solar observing, and hope to have a good a day as you two had.
The difference betweeen a prominence and a flare is not clear cut and can be easily confused and mixed up.
I'm no solar expert, but here are the basics of observable solar features:
An isolated eruption on the surface of the sun is a flare, usually energy stored in a magnetic field and violently released. (The dot in the image is the size of the Earth in relation.)
A prominence is a magnetic field loop that carries solar material with it in a arch or loop high above the disk and back down.
Filaments are the same as prominences, but only look like dark lanes against the surface of the Sun because they are simply cooler.
Now to confuse things more, here is an image of both flares and prominences in close quarters.
Granulation (Which can be seen with the Adler's H-Alpha), are convection cells on the surface...much like a boiling pot of water. The lighter areas are hotter and rising, and the surrounding darker lanes are cooler...returning into the interior.
A tremendous flare explosion or a massive prominence that over comes the magnetic field is known as a Coronal Mass Ejection. The event causes communication troubles here on Earth and the cause of great Northern Light displays.
Joe, I very much appreciate your brief , colorful and insightful tutorial. I will put the learning to good use as, hopefully, others will also.
I recall reading that both flares as well as prominences emerge from regions of concentrated magnetism, i.e. sunspots. In the case of prominences, both the starting and ending locations tend to be sunspots. Therefore, if we see sunspots and filaments near the middle of the sun's disk on one weekend, then there is a good chance of seeing great flares and prominences the next weekend once that region has rotated over to the limb.
Sure would love to see one of those Coronal Mass Ejections sometimes, but I guess they are harder if not impossible to predict.