| CD1_1 | float | Value at (1,1) of pixel coordinate translation matrix | |
| CD1_2 | float | Value at (1,2) of pixel coordinate translation matrix | |
| CD2_1 | float | Value at (2,1) of pixel coordinate translation matrix | |
| CD2_2 | float | Value at (2,2) of pixel coordinate translation matrix | |
| CRPIX1 | float | Reference pixel in X | pixel |
| CRPIX2 | float | Reference pixel in Y | pixel |
| CRVAL1 | float | Physical value of the reference pixel X | deg |
| CRVAL2 | float | Physical value of the reference pixel Y | deg |
| CTYPE1 | str | Pixel coordinate system and projection of first axis (X) | |
| CTYPE2 | str | Pixel coordinate system and projection of second axis (Y) | |
