Читать книгу The dawn of astronomy. A study of the temple-worship and mythology of the ancient Egyptians онлайн

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Suppose that the sun is rising, let a rod throw a shadow; mark the position of the shadow; at sunset we again note where the shadow falls. If the sun rises exactly in the east and sets exactly in the west, those two shadows will be continuous, and we shall have made an observation at the absolute equinox. But suppose the sun not at the equinox, a line joining the ends of the shadows equally long before and after noon will be an east and west line.

It is true that there may be a slight error unless we are very careful about the time of the year at which we make the observations, because when the sun is exactly east or west at the time of rising or setting it changes its declination most quickly. So it is better to make the above observations of the sun nearer the solstices than the equinoxes, for the reason stated.[7]

We have now got so far. If the Egyptians worshipped the sun and built temples to it, they would be more likely to choose the times of the solstices and the equinoxes than any other after its annual movement had been made out.