Hi, some UCD1+ seems incomplete, even compared to UCD1. it concerns phys.polarization and pos.bodyrc as mentionned on Unified Content Descriptor Controlled Vocabulary RFC page (http://www.ivoa.net/twiki/bin/viewauth/IVOA/UCDwordsRFC) bur perhaps also, pos.precess, pos.eop, pos.eop.nutation. -- Pierre