The Meteor and the Star Cluster

Explanation: Sometimes even the sky surprises you. To see more stars and faint nebulosity in the Pleiades star cluster ( M45 ), long exposures are made. Many times, less interesting items appear on the exposures that were not intended -- but later edited out. These include stuck pixel s, cosmic ray hits, frames with bright clouds or Earth's Moon , airplane trails , lens flares , faint satellite trails , and even insect trail s. Sometimes, though, something really interesting is caught by chance. That was just the case a few weeks ago in al-Ula , Saudi Arabia when a bright meteor streaked across during an hour-long exposure of the Pleiades . Along with the famous bright blue stars , less famous and less bright blue stars, and blue-reflecting dust surrounding the star cluster, the fast rock fragment created a distinctive green glow, likely due to vaporized metals.

Jigsaw Universe: Astronomy Puzzle of the Day