t winter solstice. This was equivalent to the assumption that the Earth was at perihelion at the winter solstice and so the <i>anomalistic year</i> was the same as the tropical year. This assumption was incorrect, but the observations in the ancient time were not accurate enough to detect the error of the assumption. So the non-uniform motion of the Sun didn't add another condition to the superior epoch. Thus, in the ideal situation, the superior epoch was the instant at which the following astronomical phe