I confess I’ve never been a real stamp collector. I tried for awhile, but coins were more my thing as a boy. My older brother was quite serious about it.
But a topic like astronomy gets my attention. So why the sun? NASA’s Solar Dynamics Observatory has been watching our star from earth orbit the last eleven years. The ten images represent the sun as filtered through different wavelengths, mostly invisible to the human eye, but give scientists information beyond the perception of our senses. Lower right seems to be visible light, with a sunspot. See?