By John Rudolph
One does not have to journey to Newgrange, Ireland or Carnac, Brittany to do Megalithic Astronomy in the ancient chambers dating to 3000 BC. Our Megalithic instrument is right here on Bainbridge Island in the reinforced concrete building housing the Ritchie Observatory
There being a full moon close to the Winter Solstice, and the night of December 19 being clouded by only a thin layer of cirrus, it seemed like a good opportunity to measure and mark the angle of the Moon when it crossed the meridian close to midnight. One of our members, Cara Cruikshank, accompanied me to Battle Point Park where we found the gates closed and locked and the key that I had did not fit the new lock. So, undaunted, we parked the car and walked to the observatory. The Moon was at least an hour from being due south so we cranked up the Ritchie 27.5" telescope and looked at the Moon. This was a new experience for our neighbor, and with the Moon one day past full, we could observe the craters on the upper edge with startling clarity. Midnight passed and the Moon was still not yet to the meridian, but we shut down the telescope and began to watch for a shaft of moonlight coming through the aperture on the circle of plywood high on the south wall of the building. Alas, some 2 x 4s interrupted the path of the light. A crowbar found in the shop made short work of removing this obstacle. Now we were ready for the moonlight.
The thin clouds and the very high declination of the Moon prevented a real visible beam of moonlight to impinge on the step of the back stairs where in a previous year, a felt pen circle marked the spot made by the summer solstice Sun. No matter, we stretched a spool of nylon fishing line from the supply shelves of the shop from the aperture to the step and aligned the barely discernable glimmer of the Moon by squinting along the string. By marking the spot with a felt pen and measuring the altitude (over and up) we were able to lay this out on the drafting board and measure the sun and Moon angles with reasonable accuracy.
It is one thing to read about how the Moon is offset 5.15 degrees from the path of the ecliptic, and quite another to see the Moon's image moving farther and farther away from the image of the Sun in the dim recesses of our concrete cave. It was my intention to work up the mathematics of just what was happening and why, but the rush of last minute Christmas doings cut off the work of your otherwise diligent researcher. Paul Middents' class will address these mysteries, and I hope to get a front row seat. Until then, the readers will have to do their own math. When you can show me what happens graphically, please call me. We wish all an interesting and blissfull NEW YEAR!!