If there's one thing I've learned after decades of studying the first human voyages to another world, it's that there is always more to discover about Apollo. Case in point: The Apollo 8 Earthrise photo that became one of the iconic images of the 20th century.
I try to be measured in my praise for spacecraft images. Not every photo can be the greatest space image ever. But this enormous mosaic showing the flattened globe of Saturn floating within the complete disk of its rings must surely be counted among the great images of the Cassini mission.