The large earth works the Hill of Tara are An Forradh (The Kings Seat) to the left in the photo and Teach Chormaic (Cormac's House) to the bottom right in the photo.
The Samhain Sunrise in early November illuminates the chamber of the Mound of the Hostages on the Hill of Tara. Samhain is the cross quarter of the astronomical year, half way between the autumn equinox and the winter solstice.