Abstract: A sighting device for use with a projectile launcher having a sighting element that is adjustable in height and an adjustment mechanism for adjusting the sighting element's height to match substantially the height of a target as apparent at the sighting device in the line of sight to the target. The sighting device further comprises a targeting mechanism that, in response to the height adjustment, automatically displaces the position of the sighting element in a generally vertical plane so that maintenance of alignment of the target in the sighting element requires the user to adjust the elevation of the launcher and, consequently, the launch angle. In one embodiment, the sighting device comprises a pair of opposed rotatable disks, the disks having respective predetermined irregular peripheries. The sighting element comprises an aperture formed between selectable portions of the peripheries along the line of sight.