Smith Astronomy Solar Images

The sun in white light (click for full size image). North is up, east is left. Notice the large sunspot on the right of the image. This is Sunspot 875, and it's larger than the earth. White light comes from the sun's photosphere, which has a temperature of approximately 5800 K (almost 10,000 F!). Sunspots are regions where the sun's magnetic field lines twist up on themselves; temperatures there are a mere 4600 K (7800 F).

April 27, 2006, UT 16:42

Telescope: Celestron Celestar-8

Aperture: 8 inches (203 mm)

Filter: Thousand Oaks Type 2 Plus

Camera: Nikon Coolpix 4300 at f/2.8, afocal projection with Sirius Plossl 40mm eyepiece

Exposure time: 1/1000 sec.

The sun at H-alpha (656 nm). This view shows the chromosphere, a layer of the solar atmosphere above the photosphere. Here we see Sunspot 875 surrounded by bright light. This is a solar flare emanating from the sunspot. You can also see a nice solar prominence at about 1 o'clock on the sun's limb (edge), as well as dark filaments, which are what prominences look like when viewed on the sun's disk. The mottled look of the sun at H-alpha is called "granulation": the bright specks are the tops of convection cells transporting hot gas from the sun's interior to its surface.

April 27, 2006, UT 17:07

Telescope: Coronado Solar Max 90

Aperture: 3.5 inches (90 mm)

Camera: Nikon Coolpix 4300 at f/4.8, afocal projection with Sirius Plossl 40mm eyepiece

Exposure time: 1/60 sec.

The sun at CaK (393 nm). The CaK line comes from a layer of the chromosphere that's slightly lower (and thus cooler) than where the H-alpha is emitted. This image was taken with a shorter focal length telescope than the other two, so it was not possible to zoom in to the same resolution. Nevertheless, Sunspot 875 is visible as a bright arc.

April 27, 2006, UT 17:27

Telescope: Coronado PST CaK

Aperture: 1.6 inches (40 mm)

Camera: Nikon Coolpix 4300 at f/4.9, afocal projection with Sirius Plossl 40mm eyepiece

Exposure time: 1/4 sec.