Constellations of the Two Hemispheres (1877) from the book by Guillemin, Amédée, (1826-1893), a celestial chart of the two… Free Image from public domain license 
Composite assembled from data acquired by the Suomi National Polar-orbiting Partnership satellite over nine days in April… Free Image from public domain license 
The NASA/ESA Hubble Space Telescope has spotted a UFO Galaxy, a NGC 2683, which is a spiral galaxy seen almost edge-on… Free Image from public domain license 
A matched trio of images of the central region of our Milky Way. Original from NASA. Digitally enhanced by rawpixel. Free Image from public domain license