Many birth charts have internal rectifying metrics.
They occur when slower moving planets make aspects to faster moving natal planets (or house cusps)culminating simultaneously with major life events that fit the energies of the planets and the geometry of the aspect. They can be used to correct an inaccurate Ascendant or simply to mark important windows of opportunity for personal planning.
The most important and active progressed aspects are the ones closest to culmination.
The importance of culmination of progressed aspects must first be understood before metrics will make sense. This is not generally taught in schools of casual cookbook pop astrology where the arbitrary 1° orb for progressed aspects is used. Noel Tyl does refer to culmination of progressed aspects within a linear time reference in his book Prediction in Astrology.
Minor aspects are important in progression.
Such “minor” progressed aspects when at or near culmination are not minor in effect, but are astrological energies that have moved into prominence in that person’s life. Not all of these are displayed in the aspectarian of the program you are using. You have to examine and compare the planet positions very closely to find some of them.
By minor we mean any 15° aspect (15, 30, 45, 75, 105, 135, 150, 165°), the quintile series (36, 72, 144°), as well as minor aspects in declination (15, 22°30′, 30, 45°). Other harmonics could be included as well.
Astrologers have conventionally overlooked culminated minor progressed aspects in reference to life opportunities and major events under the assumption that those important milestones or unique occurrences must be accompanied by the so-called major astrological progressed aspects (conjunctions, sextiles, squares, trines, oppositions). Not necessarily.
Slower moving outer planets when at or near culmination of any aspect to a faster moving natal planet (or point) can do this — so long as the energies of the planets involved actually fit the event(s) in question. Otherwise, the natal chart is off, or there is another more relevant progressed factor being overlooked.
An example of chart metrics: Sir Patrick Moore