Scattered Sunspots

Good Seeing

Sometimes observing conditions are so good it's worth setting up my solar telescope even if solar features aren't particularly outstanding. September 26th began mild and cloudless with occasional gentle breezes. Temperature ranged from 68 to 73 degrees during the morning observing window. Most importantly, the atmosphere was very steady, so there was "good seeing". No big dramatic solar features were present, just a scattered bunch of relatively small sunspots as you can see in the following 7-panel mosaic. Sunspot 3110 is the dark umbra left of center. A group of small sunspots stretches diagonally upward across the lower right. From left to right they are sunspots 3107, 3105, and 3108. The mosaic image can be enlarged to full size without blurring detail because seeing was so excellent. Next is a single close image of sunspot 3110.  The string of small sunspots 3107 and 3105 are portrayed in the next image which also looks good at full enlargement. Previous images were all made with a solar filter tuned to the exact wavelength of red hydrogen-alpha light at 656.28 nanometers. Tuning the filter away from this wavelength produces an image that fails to show surface spicules and filaments, but still shows sunspot umbras and penumbras. The next image shows many small scattered umbras in the 3107 to 3105 sunspot groups. Unfortunately, this picture has annoying vertical fringes not removed by a flat field frame.  Only one significant prominence was present on the northwestern limb. Notice spiky spicules on the top limb. The excellent observing window only lasted one hour before clouds began appearing on the southeastern horizon. Seeing conditions also deteriorated, so it was time to quit.
 

Active Solar Limb

Prominences All Around

After two months of cloudy, hot, humid weather a mild, cloud free morning good for solar observing arrived on September 15th. The sky was milky white from high thin haze. Temperature ranged from 72 to 75 degrees during my brief 50-minute observing window. Despite a promising 9:40 am start, clouds began appearing at 10:40 am and atmospheric turbulence increased. I always have to hurry to capture images before conditions worsen.

On this day only a few relatively small sunspots were present, but a nice array of prominences were scattered around the Sun's limb. These prominences were spectacularly bright and clear when viewed through the eyepiece of my solar telescope! Image quality below really doesn't match the eyepiece view this time! I wished I could have shared the view with others, but no one was available or interested, so I enjoyed them alone.

The next image is a 6-panel mosaic of the southern solar hemisphere processed to show prominences around the edge. Although the disc is, consequently, overexposed, you can still see two sunspots. The large arching prominence on the lower left is really grand! Northern hemisphere prominences were also numerous as shown in the next 6-panel mosaic. Activity associated with departing sunspot 3098 in the upper right included some spiky eruptions. These show more clearly if you enlarge the image by clicking on it. Here's an enlargement of sunspot 3098 and its spiky emissions. Two sunspots in the southern hemisphere appear in more detail in the following imperfect 6-panel mosaic processed to show disc detail instead of prominences. Sunspot 3102 is on the left and sunspot 3100 is right of center. Next is a closer view of sunspot 3102. This long lasting sunspot previously disappeared around the Sun's western limb almost three weeks ago. As the Sun rotated it then traversed across the solar back side for almost two weeks before emerging around the eastern limb to appear as it does in the image below. The large arching prominence was near sunspot 3102. The suspended arch was considerably dimmer than its base near the limb. I always have trouble making prominences stand out from noisy background. Prominence detail is hardly improved in the following yellow colored image with blacked out disc. I  look forward to cooler weather and clearer sky as autumn begins.