Blue Arcs Toward Andromeda
Now, over 550 hours of combined exposure and a collaboration between amateur and professional astronomers has revealed strong evidence for their true nature: SDSO 1 is not intergalactic, but a new class of planetary nebula within our galaxy. Dubbed a Ghost Planetary Nebula (GPN), ...
APOD: https://apod.nasa.gov/apod/ap250804.html