Sunspot Regions

SOHO MDI Magnetogram Tutorial

Getting to the Data

The easiest way to view this image is by opening the Space Weather Media Viewer. In the "IMAGES" section select "The Sun" from the small drop-down menu. Select the image called, "MDI Magnetogram- SOHO Mission". Don't forget to zoom in and pan to the top center of the image in order to see the exact date and time of the image.

About the Data

The MDI instrument aboard the SOHO spacecraft 'can' detect the strength and locations of magnetic fields on the Sun and represent that information in specialized images called magnetograms. These images demonstrate the intensity of magnetic twisting in the solar photosphere.

The magnetogram image shows the magnetic field in the solar photosphere, with black and white indicating opposite magnetic poles. You are probably familiar with a bar magnet. One end of the bar has a north magnetic pole and the other end has a south magnetic pole. The white areas are regions of north magnetic poles and the black shows regions of south magnetic poles. The gray color shows an absence of magnetic fields. The colors, back, white and gray, are artificial.

The magnetogram can help to predict solar storms. When the black and white areas next to each other are clearly separated, there is less chance of a solar eruption. When black and white areas are mixed together, there is a better chance for a solar eruption from that location.

Navigation Tips

With any image in the Space Weather Media Viewer you can zoom and pan. This feature allows you to see sunspots on the Sun in great detail along with the relative size of Earth. Some small sunspots may not be visible until you zoom.

The box marked "Details" found in the lower right hand side of the Space Weather Media Viewer screen will provide additional information and a link to the Solar and Heliospheric Observatory website.