The web portal for UNESCO’s Astronomy and World Heritage Initiative exists to raise awareness of the importance of astronomical heritage worldwide and to facilitate efforts to identify, protect and preserve such heritage for the benefit of humankind, both now and in the future.
Serving UNESCO’s Astronomy and World Heritage Initiative, the portal aims to open pathways for co-operation between, and the sharing of knowledge among, State Parties to the World Heritage Convention, the academic community, and other individuals and organizations with a strong interest in promoting and safeguarding the planet’s most precious astronomical heritage.
It has just released a detailed dossier of the Stonehenge area Astronomical Heritage.
Just follow the link for a wealth of detail. Of course my own pet theory of an alignment of the Great Trilithon across its width, and the other associated stones, including the Altar Stone, isn't mentioned. I flatter myself in thinking that it is too recent to have been considered during the write up but take comfort from this line: "it is possible—perhaps even likely—that other astronomical alignments and sites existed within the WHP and are waiting to be discovered."