Two Images of the Sun

These two pictures of the Sun were taken on April 19, 2012. The red-light image was taken at 12:55 pm, just before we opened the Observatory for public viewing, and the white-light image was taken at 3:16 pm, as we were closing for the day.

Both telescopes use safe solar filters that block 99.999% of the incoming sunlight. The lefthand image shows the photosphere, the surface of the Sun, which emits a continuous spectrum of light. When combined, its light is white with a yellow tinge. 

The most dramatic feature of the photosphere are sunspots.  The Sun is covered in sunspots today. Many of them are new, having grown from a blank part of the Sun in just the last few days.  A sunspot is an area of intense magnetic activity on the Sun, slightly cooler than the surrounding photosphere. Solar flares and coronal mass ejections often occur in sunspot regions. The larger of the spots on the Sun today are slightly larger than the Earth.

The sunspots are also visible in the righthand image, taken with a telescope equipped with a hydrogen-alpha filter. This filter blocks out all colors of the sun except for one narrow shade of red, emitted by excited hydrogen. This is a good way to isolate light from the atmosphere of the Sun (which is called the chromosphere because of its color).

While sunspots are features of the photosphere, not the chromosphere, dramatic ones can be seen in the red-light image. Bright regions can also be seen near the sunspots. These are plages, clouds of hot gas which float in the chromosphere above sunspots.  Finally, some prominences can be seen around the edge of the Sun. These are arches of hot gas following magnetic loops above the Sun's surface.

White light telescope: Televue 85mm with AstroSolar ND5 film solar filter.

Red light telescope: Lunt 100mm hydrogen-alpha telescope.

Camera: Lumenera SKYnyx 2-2M