The discovery images were taken on May 15 , 2005 and May 18 , 2005 ; the moons were independently found by Max J. Mutchler on June 15 , 2005 and Andrew J. Steffl on August 15 , 2005 . The discovery images were taken on May 15 , 2005 , and May 18 , 2005 ; the moons were independently discovered by Max J. Mutchler on June 15 , 2005 , and Andrew J. Steffl on August 15 , 2005 .