The Sun approaching Solar Maximum
This unusual and very interesting postcard came as a birthday gift from Ruth Smith :) It is named "The Secrets of the Sun" and shows three EIT images. From the back of the card: A comparison of three Extreme Ultraviolet Imaging Telescope images nearly 3 years apart illustrates how the level of solar activity has increased. The progression toward more active regions and the number and size of magnetic loops are unmistakable.
Thanks a lot for this gift card, Ruth :)