Stephan's Quintet (counterclockwise starting at the 5:00 position) consist of NGC 7320 (a foreground spiral), NGC 7319, NGC 7318-1 and NGC 7318-2. NGC 7319, NGC 7318-1 and NGC 7318-2 are interacting with the latter two merging to form an new system, NGC 7319 will eventually join the merger. NGC 7320 is not involved in the merger or interaction.