The Data

This compact disc contains over 5,000 solar magnetograms obtained on every clear day which the KPVT magnetograph was operational since 1974--slightly more than a complete 22-year magnetic cycle.

The data are formatted as black and white PNG images with each pixel indicating the line-of-sight magnetic field strength in the corresponding area on the surface of the sun. Gray areas are neutral (no field) while shades of black or white indicate strength of field pointing away or towards the observer, respectively. The pixel values range from 0 (white) to 255 (black).

The images are always oriented with solar (heliographic) north at the top, and west to the right, as is conventional in astronomical images (but opposite geographic maps). The PNG images contain 447 X 447 pixels, although the original spectromagnetograph images are 1788 X 1788 (a factor of four better spatial resolution).