is composed of 30 degrees, each astrological age might be thought to last about 72 (years) × 30 (degrees) = about 2160 years. This means the Sun crosses the equator at the vernal equinox moving backwards against the fixed stars from one year to the next at the rate of one degree in seventy-two years, one constellation (on average) in about 2160 years, and the whole twelve signs in about 25,920 years, sometimes called a Platonic Year. However the length of the ages are decreasing with time as the rate of precession is increasing. Therefore, no two ages are of equal length. First point of Aries alignment - the fiducial point Approximately every 26,000 years the zodiacal constellations, the associated sidereal zodiac, and the tropical zodiac used by western astrologers basically align. Technically this is when the tropical and sidereal "first point in Aries" (Aries 0°) coincided. This alignment is often called the fiducial point and, if the fiducial point could be found, fairly exact timeframes of all the astrological ages could be accurately determined if the method used to determine the astrological ages is based on the equal-sized 30 degrees per age and do not correspond to the exact constellation configuration in the sky. However this fiducial point is difficult to determine because while there is no ambiguity about the tropical zodiac used by western astrologers, the same cannot be said of the sidereal zodiac used by Vedic astrologers. Vedic astrologers do not have unanimity on the exact location in space of their sidereal zodiac. This is because the sidereal zodiac is superimposed upon the irregular zodiacal constellation, and there are no unambiguous boundaries of the zodiacal constellations. Modern day astronomers have defined boundaries, but this is a recent development by astronomers who are divorced from astrology, and cannot be assumed to be correct from the astrological perspective. While most astronomers and some astrologers agree that the fiducial point occurred in or around the 3rd to 5th centuries AD, there is no consensus on any exact date or tight timeframe within these three centuries. A number of dates are proposed by various astronomers and even wider timeframes by astrologers. (For an alternative approach to calibrating precession, see Alternative approach to calibrating precession in New, alternative, and fringe theories section below). As an example of a mystic contemporary approach to precession, in Max Heindel's astrology writings, it is described, that