1,311. Adjusting the Moon's Average Based on the Sun's Location

Hilchos Kiddush HaChodesh 14:4

Continuing the average of the moon’s path, the remainder of its progress in a regular year is 305 degrees, zero minutes, 13 seconds (305, 13). The position of the moon’s average for the Rambam’s chosen starting point (Wednesday night, 3 Nisan, 4938) was 1 degree, 14 minutes, 43 seconds (1, 14, 43) in Taurus. The average of its path at this time was 84 degrees, 28 minutes, 42 seconds (84, 28, 42). Now that we know the average rate of progress for the moon’s average and its position at the time of our starting point, we can calculate the position of the moon’s average on any date desired, just as with that of the sun. After calculating the moon’s average at the start of the desired, we turn our attention to in which constellation the sun will be located at the same time.

Hilchos Kiddush HaChodesh 14:5

If the sun is located between the middle of Pisces and the middle of Aries, the moon’s average is left alone. If the sun is between the middle of Aries and the start of Gemini, 15 minutes are added to the moon’s average. If the sun is between the start of Gemini and that of Leo, 30 minutes are added to the moon’s average. If the sun is between the start of Leo and the middle of Virgo, 15 minutes are added to the moon’s average. If the sun is between the middle of Virgo and that of Libra, the moon’s average is left alone. If the sun is between the middle of Aries and the start of Sagittarius, 15 minutes are subtracted from the moon’s average. If the sun is between the start of Sagittarius and that of Aquarius, 30 minutes are subtracted from the moon’s average. If the sun is between the start of Aquarius and the middle of Pisces, 15 minutes are subtracted from the moon’s average.