Great Pyramid Stellar Orientation

Nature's 2000/11/16 cover article offered two ursal stars' verticality as providing north for the ancient pyramid builders, placing the Great Pyramid of Khufu in middle of the 25th century BC, an unorthodox date. The present authors propose more accurate methods using stars far nearer the North Celestial Pole c.2600 BC, which happens to be near the orthodox date for Khufu. The 4.6 magnitude star 10i Dra was ideally placed c.2610 BC and thereabouts for circling over the pole near the Winter Solstice when its inverted semi-circular path could be seen for a half-day and simply bisected to find north.