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The Solar Disk Is Not Blank Any More Even Through a Small Telescope

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

On 2011 November 10, for example, 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. We set the telescope on the Sun. At 
least eight sunspot groups were visible with dozens of individual 
spots readily seen even through a three-inch refractor telescope from 
Gainesville, Florida.  (See the left image in the attached jpg.)

Compare this view with the SOHO/NASA spacecraft image taken 
approximately four hours earlier in visible light at a wavelength of 
about 680 nm (right image). This is similar to the transmission of 
the solar filter used on the three-inch telescope.

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.

So, small scopes are not just for kids.

Photo Details: Unguided photo taken through a full aperture Thousand 
Oaks Type 2+ Glass Solar Filter (transmission 1/1,000 of 1%) using a 
Tele Vue 76 mm aperture, f/6.3 APO refractor telescope with a 480 mm 
focal length and equipped with a Tele Vue 4x Powermate Amplifier for 
an effective focal length of 1,920 mm. Camera Used: Canon EOS 5D Mark 
II; Exposure 1/250 at ISO 800; effective f-stop f/25; White Balance 
Auto. This is a single image photograph taken 2011 Nov. 10 at 18:26 
UT with some minor processing using Canon ZoomBrowser EX.

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