Sunspots, Old and New

Unexpected Activity

Thin early morning clouds cleared on May 7th leaving nearly clear skies, a light breeze, and temperature in the mid-60's. In a welcome change from the recent sunspot drought two spots and some prominences were on display this morning. The following 17-panel mosaic shows the unexpected features on the Sun's eastern hemisphere. (Click on the image for a larger, more detailed view.)

Sunspot 2740, on the right, is actually the same as old sunspot 2738. Sunspot 2738 remained intact long enough to travel across the Earth-facing solar disc a couple weeks ago, disappear around the western limb, travel across the solar far side, reappear on the eastern limb with a new number, and travel about one third across the solar disc again when this image was made on May 7th. A few days later it disintegrated leaving behind only its newer companion, sunspot 2741, seen near the eastern limb.

A nice array of prominences were scattered along the eastern limb as shown in the next 5-panel mosaic. Longer exposure time was used to capture relatively dim prominences. The overexposed solar disc has been blacked out, dim light levels enhanced, and yellow color added. It takes some work to make the prominences stand out above the background. I used both dark and flat field frames for this mosaic.

Both sunspots and a few prominences are captured in the next two single frame views. The first image was processed to bring out limb details. Notice the extended dark filament rising from the right side of sunspot 2740 in the first image. This was a transient eruption, as you can see by comparing the first image with the second image below taken 40 minutes before the first image.

It's difficult to preserve light and dark features in a sunspot umbra without decreasing the contrast of dark spicules. The next two images show this for sunspot 2740. The first image was processed to preserve umbra details. The second image was processed to show greater spicule contrast. (Click on the images to better see the umbral details.).

Solar minimum grinds on. Who knows when the Sun will display this number of features again.