Find middle point of quad (P1, P2, P3, P4) (marked as X) 3. Find tangent plane of the middle point 4. Project all the stars with the tangent plane (green dots) 5. Find star coordinates from photo 6. Find transformation matrix from photo to stars of tangent plane using P1, P2, P3 7. Apply transform to Pn of photo (red dots) P1 P2 P3 P4 P5 P6 P7 P8