I recently attended ConVersion here in Calgary and found a fellow selling old SF pulps in great condition.
The oldest, from 1939, is from an era before we had the photo quality we get now from probes and imaging systems. So the depiction of a Jupiter-like planet and the cast shadow across the rings really caught my eye. And the understated, modern typography gridded out makes this composition sing. Just a few months earlier, they had been using the more decorative type design that had been prevalent through the Teens and Twenties.