Bland Sun

Farewell February!

More than two months passed since my December solar observing session. During this time the Sun presented a mostly bland countenance. Lack of dramatic features continued on February 28th, but observing conditions were so nice I decided to capture some images anyway. It was 64 degrees with mild wind gusts from time to time. Seeing was mediocre. I got a late start at 2:47 pm. Only one modest sunspot, a pair of small filaments, and two nice prominences were visible.

The first image below shows the Sun's eastern side with one significant prominence near the top and a small emerging sunspot near the upper right edge. The image is a cropped 15-panel mosaic made with a 5X Barlow lens.

Notice the bright area in the lower right corner of the previous image. This was caused by my own carelessness in obtaining a flat field. A flat field image is supposed to record camera response to a uniform light source. My flat field image was taken too close to the solar limb. Limb darkening caused a brightness gradient across the flat field image. This brightness gradient was then incorporated into every image subsequently processed with the faulty flat field. I can't believe I did this when I know better! Next time I'll be sure to get my flat field close to the center of the Sun.

Some of the unfortunate brightness gradient can be seen in the following 3-panel mosaic showing modest sunspot 2506 with two filaments beneath it. The detail in this image is fairly good in spite of the mediocre seeing.

There were two nice prominences. This one was on the eastern limb.

Another prominence was on the western limb.

Finally, there was a small emerging sunspot with magnetic arches. This was visible near the upper right edge in the first image above.

I hope the Sun perks up in the next few months. Otherwise, 2016 will be a dull year for solar action.