An adjustable optical apparatus adapter is disclosed to include a camera platform provided with a mounting screw and a wing nut for securing a camera to the camera platform, a telescope holder for holding a telescope, a holding down frame controlled by a lock screw to hold down a telescope in the telescope holder, and a camera platform lock mounted in the a horizontal sliding slot in camera platform and a vertical sliding slot in telescope holder for locking the camera platform to the telescope holder after position adjustment of the camera platform horizontally and vertically relative to the telescope holder to have the loaded telescope at the telescope holder in axial alignment with the loaded camera at the camera platform.