Incompatibilities

On the other hand, CG02 section 6.1.4 stress that the AIPS convention cannot represent oblique celestial coordinate graticules such as the one shown in [their] Fig. 2. CRVALi for these projections [(AIT/Aitoff, GLS/radio, MER)] in AIPS does not correspond to the celestial coordinates $(\alpha_0,\delta_0)$ of the reference point, as understood in this formalism, unless they are both zero in which case no translation is required. In other words, these 3 projections do not fit into the CG02 general formalism (unless the reference point is on the Equator). See next subsections for details.