The Photon Cannon is a weapon that appears in He-Man and the Masters of the Universe.
The Photon Cannon was used by Man-At-Arms and Teela to defend Avion when King Von and his Torgs, attacked it to capture Stratos and the Staff of Avion.
Although Man-At-Arms was familiar with the controls of the device, Teela was not. Luckily, she was a self proclaimed 'fast learner'.
Later, when the inhabitants of the Royal Palace were suffering from nightmares induced by Darkdream, the Photo Cannon weapons were visible in the background as Prince Adam and Teela run through the Palace to their Sky-Sleds.