An aiming device including a thermoelectric module, a light source and a sight element. The thermoelectric module generates electricity from a thermal gradient, produced from a user's body heat that is transferred to the module. The electricity powers the light source. The light source illuminates a sight element of a projectile shooting device to enhance visibility of the sight element in a variety of ambient lighting conditions, optionally in low light conditions. The aiming device can be mounted to a projectile shooting device. With the aiming device, a user can selectively illuminate a sight element of a projectile shooting device, with the user's own body heat, to assist aiming the projectile shooting device during a shooting activity. The projectile shooting device can be any type of archery bow and/or firearm. Related methods are also provided.