Lunar Window

The calculator uses the tropical zodiac: twelve equal 30 degree sections of ecliptic longitude beginning at Aries.

Simple mode starts with the Sun sign you choose, then calculates the next time the Moon enters and leaves that sign.

Precise mode first calculates your tropical natal Sun longitude from a UTC birth instant. It derives the Sun sign and degree from that longitude, then calculates the Moon's next ingress, exact crossing of that degree, and egress.

The lunar transit itself is astronomical and calculable. The Sacred Secretion interpretation is different.

Claims that this period corresponds to a special secretion from the claustrum, or to a substance descending and ascending the spine, are part of an esoteric teaching. They are not established findings in neuroscience.

This tool is intended to calculate the astronomical window associated with that tradition, not to prove the biological claims.

I came across a teaching sometimes called Sacred Secretion or Sacred Oil. One part of the teaching associates a recurring personal period with the Moon passing through the zodiac sign occupied by the Sun at birth.

That made me wonder when the astronomical part actually happens, so I built a small calculator for it.

The tool calculates the Moon's geocentric ecliptic longitude and searches for the next times it crosses the selected sign boundaries. All calculations run in UTC and are formatted in the selected timezone using IANA timezone rules.

Geographic coordinates are not used for topocentric positional astronomy in this version. For the natal Sun calculation, the important input is the UTC birth instant, which is resolved from birth date, optional birth time, and timezone.