Astronomy is a mature open science community with advanced ecosystems for data sharing, yet these systems face semantic interoperability gaps due to fragmented semantic artefacts —ontologies, vocabularies, thesauri, etc.— scattered across diverse sources, not always compliant with semantic Web standards (e.g., OWL or SKOS) and overlapping in scope. The FAIR-IMPACT and OPAL projects utilized OntoPortal technology to create a unified semantic artefact catalogue for astronomy, enhancing management, sharing, and exploitation of FAIR semantic artefacts and improving their discovery and reuse within the community.