Spotty

The Sun on Sunday 28th April 2013
with Sunspot group AR1726

The Sun was nicely spotty on Sunday and I managed to take this rather blurry photo of sunspot group AR1726 as it moved slowly across the Sun's disc.  Sunspots are cooler than the surrounding solar photosphere and so appear dark. They are however quite hot, being between 3000 and 4500 degrees K. The photosphere is however very very hot, approximately 5800 degrees K!  Strangely, further out from the Sun's photosphere, in the corona (the glowing solar plasma 'atmosphere' that becomes visible during a total solar eclipse), the temperature rises to over a million degrees K and that's very very very hot!

Please do not stare at the Sun as this will cause considerable damage to your retina.  On no account look at the Sun through binoculars or a telescope as such activities will cause permanent damage and most likely the complete loss of sight.  I use special equipment to view and take photographs of the Sun.

Sunspots are temporary phenomena associated with intense magnetic activity.  As we are now at 'Solar Maximum' in the Sun's eleven year activity cycle the number of sunspots visible has increased.

Active Region AR1726 is roughly 150,000 Kilometers long