The standard coordinates are then corrected for the effects of radial field distortion:
These effects should be negligible for the JKT f/15, INT f/15 and WHT f/11 foci, but corrections are required for WHT and INT Prime and JKT f/8. In particular, WHT Prime requires precise location of guide stars, since the autoguider field is small. The formula: is appropriate, with coefficients as given in Table 1.
Configuration | ||||
WHT Prime | 1.2797 | 27.458 | 24320.0 | 0.0 |
INT Prime | ||||
JKT f/8 | 0.0 | 13.32 | 0.0 | 0.0 |