Solar arc chart
Solar arc is a direction technique that moves every point in the birth chart forward by the same amount. The amount of movement is the arc the Sun has traveled since birth in secondary progression. Since the Sun advances about one degree a day, the arc grows by about one degree a year: around 29° at age 30 and around 44° at age 45. Because the planets, Ascendant and MC move together, the aspects in the birth chart are preserved; what changes is the new position of these points relative to your birth chart.
In interpretation, solar arc looks at the years in which a planet forms an exact aspect to a planet or angle (Ascendant, MC) in your birth chart. The orb is kept tight, usually 1°; this means the effect spreads over roughly a year before and after the exact date. Solar arc Sun conjunct the MC can describe a visible step in your career, and solar arc Saturn square the Moon a period of emotional responsibility. The technique is used especially for timing turning points such as moving, marriage or a change of job, and it gives the soundest results when read alongside transits. Themes involving the Ascendant and MC require an accurate birth time.
