Thursday, September 20, 2012

Tri-band solar imaging - part 3

In the previous blog posting I posted a question: how will spicules and prominences appear at the solar limb? I am using a color scheme that arranges the most detuned image as red, medium detuned as green and not-detuned as blue. When seen in silhouette against the photosphere spicules and filaments are revealed by their absorption of H-α light. They look dark in H-α images and since this is blue in my color scheme they will appear reddish. When seen against the blackness of space these same features are revealed by their emission of H-α light - and appear bright in the blue (H-α) channel. Check it out for yourself below!
Active region 1193 on April 22 -2011, with many internal color variations. The chromospheric limb appears bright blue since here we see H-alpha emission which I choose to map into the blue color channel. When seen against the photosphere the same features are revealed by their H-alpha absorption and thus appear reddish. Click image for full size view.
Now, take a shot and guess how a flare will appear in a tri-band image! I will show a picture of one later.

I had a hard day at work and blogged too late into the night yesterday, so you'll have to wait until tomorrow for the next posting where I will discuss acquisition aspects of tri-band imaging.

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