English: Airplanes, satellites, Muon's, Worm's/ Gamma rays.... Normally we remove all the traces of cosmic radiation and human Engineering visible in the Sky. Radio-active particle traces and Gamma rays have to be removed also. It is kind of busy in the Sky these days as shown here in this stack of 223x300 second exposures made without fancy statistical cosmetic outlier removal Nasa APOD: <a href="https://apod.nasa.gov/apod/ap191014.html" rel="noreferrer nofollow">apod.nasa.gov/apod/ap191014.html</a>