Sunspot

Some predictions indicate future sunspot cycles may show declining activity. However, the current cycle seems to be gearing up with more sunspots, flares and coronal mass ejections than have been observed in several years. Even a good, small telescope (equipped with a safe solar filter) easily shows the sunspot increase.

Sunspot



On November 10, I was helping my grandson earn his Cub Scout Belt Loop, one requirement is to set up and demonstrate how to focus a simple telescope and we decided to aim my three-inch refractor at the Sun. At least eight sunspot groups were visible with dozens of individual spots readily seen from here in Gainesville, Florida (top left image).

Compare this view with the SOHO/NASA spacecraft image taken approximately four hours earlier the same day in visible light at a wavelength of about 680 nm (top right image). This is similar to the transmission of the solar filter used on my three-inch scope. Notice the small telescope image shows not only sunspots, which are cooler than their surroundings, but also the Sun’s limb (edge) darkening. In addition, several white light faculae are visible near the left and right edges of the Sun. These are brighter and hotter areas of the Sun’s visible disk (photosphere) and best seen near the solar limb against the darker background of the limb darkening. Small scopes aren’t just for kids.

The lower photo shows sunspot regions AR 1302 and 1305, observed in October 2011, in comparison to the size of the Earth.

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