← Reference · 06 of 07

Moving one chart forward in time

The natal chart is fixed at birth. Two older techniques move it forward — one by a strange arithmetic, the other by a real astronomical return — and they are not the same kind of claim.

A secondary progression is "a day for a year": the sky on the Nth day after birth is read as the sky of the Nth year of life. There is no physical mechanism connecting the two — the technique is a symbolic correspondence, old enough that nobody now claims otherwise — and the only thing this site asserts about it is the arithmetic, which is exact rather than rounded to whole days. Age is measured in tropical years (365.24219 days, the Sun's return to the equinox, not the calendar's 365.25) and added to the natal Julian Day as a fraction, so a progressed position moves smoothly through a year rather than jumping from one whole-day sample to the next.

The consequence of a day standing for a year is that the fast bodies do almost all the visible moving. The progressed Moon covers roughly a sign every two and a half years — the traditional 'progressed lunar cycle' driving a person's twenties through fifties — while the progressed outer planets barely move at all across a lifetime; Pluto's fastest year-per-day rate still amounts to a fraction of a degree. Progressed aspects are read on a tight orb here (2° at most) for exactly that reason: a progressed contact can sit within a degree for a year or more, so a wide orb would leave everything permanently 'in effect' and say nothing about timing.

A solar return is a different kind of thing entirely: an actual moment when the Sun crosses the exact ecliptic longitude, minute and second it held at birth, found the same way this site finds a sign ingress — by solving the crossing directly rather than approximating it. That instant lands within roughly a day of the birthday but almost never on it, and drifts from year to year because the tropical year is not a whole number of days; the site computes the anniversary from that tropical year rather than from the calendar, which is what lets a 29 February birth get a solar return every single year instead of once every four.

The return is cast for wherever a person actually is when it happens, not for the birthplace — location is a required parameter, not a default — because the Ascendant of a return chart is the part that moves most with the observer's coordinates, and it is traditionally the part most read. Two return charts cast for the same instant but different cities can show markedly different Ascendants, which is a real geometric fact and the entire reason the technique treats travel as meaningful.

The distinction worth keeping straight: a progression is a symbolic rule applied to real ephemeris data, with no pretence that day 11,000 after birth is astronomically anything. A solar return is real ephemeris data at a real moment — the Sun truly is back at that degree, wherever the person is standing. Both are drawn on this site with the same computed precision as the natal chart itself; only the natal chart's own reading is a plain record of the sky at birth. These are constructions on top of it, and are named as such everywhere they appear.