Simulated Solar Rotation using Calcium K Spectroheliograms.
July 6 to 13, 1925

There are 70 images in this sequence with a total of 4.1 Mbytes. Depending on your browser, the rotation simulation will start after a substantial fraction of these have been downloaded. Seven different Ca K spectroheliograms make up the basis for the sequence. They are separated from one another by 24 hours. The amount of rotation during one day makes it difficult to track persistent features. In order to make this persistence more evident, each image was distorted by up to + and 1 0.5 days. The first and last days are represented by five images while all other days have ten. By focusing attention on individual features in the images, it is possible to see that even weaker features continue to be present for periods over 24 hours.

The simulation will loop until you press your back button.