July Heat

Dripping Sweat

July and August bring heat and humidity to Williamsburg. Tropical conditions were discouraging on July 21st. Nevertheless, a clear morning sky tempted me to image some sunspots. After a dawn bike ride I hurried to set up the solar telescope as temperature rose into the lower 80's. By the time I started capturing images my shirt was drenched and sweat dripped from my head. Humid air was completely still. I needed a towel to keep from soaking my laptop and note papers.

As I've mentioned before, the Sun has been nearly featureless lately. When a couple of rare significant sunspots were present on July 21st I was motivated to observe them before they rotated out of view. The first image below is a 26-panel mosaic of the Sun's western side showing sunspot 2565 closest to the western limb with sunspot 2567 following further from the rim. A few small prominences sit on the limb. Unfortunately, subtle vertical bands are visible. For some reason flat fielding failed to remove the bands this time. Seeing was good, so features are sharp. (Click on the images for a larger view.) 

The next image is a close detailed view of the sunspot pair.

Most of the Sun was blank, as you can see from the first mosaic image above. On the eastern limb one dark filament floated near a prominence shown in the final image below.

Clear sky lasted just 33 minutes! As temperature rose toward 90 degrees clouds suddenly filled the sky. I struggled to capture a flat field frame between cloud gaps while suffering in the exhausting heat. Once all my equipment was moved inside I collapsed into a chair for a late breakfast. Later that afternoon we cooled off a bit on water slides at Water Country.

Sunspot Drought

Filaments

When unexpected clear skies appeared early in the morning on June 30th I hurried to set up my solar telescope. It had been six weeks since I last imaged the Sun. With no wind, and temperature near 80 degrees, conditions were relatively pleasant. Good observing conditions are fleeting, however. By the time I was ready to record the first image thin clouds were spreading across the sky. During the next hour clouds thickened and I struggled to capture images through cloud gaps.

The Sun continues its slow journey toward sunspot minimum. On June 30th seven days had passed without any sunspots. The only visible features were a collection of filaments and a few modest prominences. Seeing was good, so the pictures below show nice detail even though many were recorded through thin clouds. The first image is a 28-panel mosaic (reduced to one third of its original size!) showing filaments on an otherwise bland surface. (Click on the images for larger views.) 

Next is a closer view of the filament group processed to increase contrast between bright and dark features.

The last image shows a prominence visible on the southeastern limb.

This observing session illustrated, once again, how hard it is to achieve excellent observing conditions. A perfect day would have good seeing, a variety of dramatic features on the Sun, and cloudless skies. June 30th had good seeing, but only relatively bland solar features seen through increasing clouds.