For the Radio Ulster programme Your Place and Mine I visited the Knockmany Chambered Cairn just outside Augher. Professor Mark Bailey is the Director of the Armagh Observatory and Edith Logue works for the NI Environmental Agency.
You can read more about Knockmany here: http://star.arm.ac.uk/Knockmany/ on the Observatory website. After broadcast, Ill add audio recorded at the chamber. (less info)