Tangent Plane Test
1. Convert RA/Dec to 3d coordinates
2. 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