... But the skilled and careful astronomer also went on to discover star clusters, comets, asteroids, and clusters of galaxies. ... IC 4628: The Prawn Nebula . ... Nearby hot, massive stars, millions of years young, radiate the nebula with invisible ultraviolet light, stripping electrons from atoms. ... At the time the comet (center) was in the close foreground, a mere 9 light-minutes from planet Earth, with the galaxy a more substantial 60 million light-years distant. NGC 7635: The Bubble . ...