Chapter 3 - Astronomical Phenomena

The rising and setting of the Moon, Sun, planets, and stars and the phases of the Moon arise from the relative motions of these bodies with respect to the Earth. The Earth rotates about its axis once a day producing an apparent motion of the celestial sphere. In the Northern hemisphere, the north celestial pole is above the horizon. The celestial objects rise in the east and set in the west and reach their highest altitude above the horizon when they cross the local meridian.

The time of Sunrise, Sunset, and twilight, Moonrise and Moonset, the phases of the Moon, and the rising and setting times for planets and stars are calculated in the following sections of this chapter. The methods employed to provide these times are accurate to one or two minutes, usually all that is required in planning observations. The user should be aware of the limitations of the algorithms used for predicting times far into the past or the future. Orbital elements of the Sun and Moon have been expressed as power series in the time. Extrapolating beyond a few centuries from the present time may produce unacceptable errors.

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