Re: When does Orions belt reach the top of its precessional cycle at meridian?

Precession is the motion caused by the pull of gravity from the Sun and Moon on the equatorial buldge of the Earth as it rotates. It's the same kind of motion you see when you see a spinning top wobble. It takes about 26,000 years for the axis of rotation to move all the way around the circle described. If the stars of Orion's belt were at a low point crossing the meridian when the pyramids at Giza were built, it would be about 13,000 years later when they would be at their highest crossing of the meridian. (I'll have to assume your statement that they were at a low is correct.)

It seems to me the pyramids went up around 3000 BC, that would put the north celestial pole somewhere around Thuban in Draco. 10,000 years from now the pole will be somewhere along the edge of the group of stars called the Summer Triangle, between Cygnus and Lyra.