Our calendar is based on patterns in the heavens – the earth’s rotation, the phases of the moon, the orbit of the earth about the sun. Our calendar has its origins thousands of years ago, from Egypt. By keeping close watch on the sun’s progress through the sky, ancient Egyptians were able to accurately measure the length of the year, and knew it was about 365 and a quarter days long. Their calendar had 12 months of 30 days each, which worked out to 360 days total. Then they had five extra days or “empty” days, known as heiru renpet, which they used as a holiday at the end of the year. The new year began with the predawn rising of a star they named Sothis, which appeared in the east just before sunrise. This happened in July, around the time each year when the Nile River flooded. Sothis is still shining up there; we call it Sirius, the dog star, the brightest star in the night, which appears below and to the left of the constellation Orion, in the southern sky these early winter evenings.