June 9, 2018 8:55 pm
What is the difference between the illustration on the left and that on the right? They both show the Big Dipper revolving around the North Pole as seen from Stone J at the Kanayama Megaliths.
The answer is: the left illustrates the revolution of the Big Dipper in modern times; the right is how it looked to the Jomonese 5,000 years ago when the Kanayama Megaliths were young. The Big Dipper is now further away from the North Pole than it was during Jomon times.
This is part of the post, http://blog.livedoor.jp/kanayama_tour-kanayamamegaliths . This summer, from around 8 pm, we can see the North Pole star from J-stone at Kanayama Megaliths.
The current North Star is the Polaris star which is the alpha star in Ursa Minor. Stars around it rotate around this star. The photo above shows the stars visible to the naked eye. It is rather faint to see due in part to noise suppression in the digital camera. This was taken from our research center tonight. Big Dipper is in the upper left. The two stars in the bowl point to the North Star. Near the bottom right is the North Star. In the northern sky, the stars rotate around this North Star. The Big Dipper also rotates a lot in the sky.
Above is the same image with constellation lines drawn in to help your visualization. The arc is part of the circle of the precessional path. Note how close the Big Dipper is to Thuban, the Pole Star of the Jomon.
Upper left: Big Dipper in Ursa Major. Center red arrow: Thuban in Draco. Purple: Polaris in Ursa Minor
The Pole Star now is Polaris, one of the stars of Ursa Minor. During the Jomon period, the Pole Star was Thuban, Alpha Draconis. The reason for the change: precession. In the image below, Kochab has been added in yellow. Kochab is the brightest star in bowl of Little Dipper, slighter fainter than Polaris.
Compare the rotation of the Big Dipper centered on the current Polaris star, and the rotation centered on pole star Thuban around 2500 BCE. Thuban, the pole star of the past, was much closer to the Big Dipper compared to the present, and the range of rotation is narrow.