Age Harmonics are based on taking the locations of the planets/points at birth and multiplying them by the factor of your age.  As these factors change rapidly with minor adjustments of the birthtime, a very precise birthtime is needed to get reliable information from this technique. This technique is mainly employed in one of two ways. For a specific time-period, the exact age at that time is used as the harmonic factor.  (to be multiplied by the natal positions) For looking at years, we use the exact harmonic for that year and treat that chart as the “year’s chart.” Here, the allowable orb needs to be about 1° or so.  (though I tend to stretch it to 1° 21’ of arc, my normal transit orb) It is to be noted that the age harmonic chart produces a valid chart for events, both in and of itself (in terms of normal understanding of factors), as well as in aspect to natal factors.  Note that (for instance) a 0° 15’ error in the Midheaven (1 minute error of time), will result in a 7° 30’ error by the time one is 30 years old!  Since we are only considering around 1° aspects, one can see that obviously the system breaks, unless that birthtime is very tightly-defined.  (meaning seconds, not minutes)