Venus Sign Calculator

A Venus sign is the zodiac sign holding Venus at birth, measured as ecliptic longitude on a 360 degree circle divided into twelve 30 degree segments starting at the vernal equinox point. Venus completes one orbit in 224.701 days, but its apparent motion seen from Earth is governed by the 583.92 day synodic cycle, during which it swings from morning star to evening star and turns retrograde for about 41 days. Because Venus never appears more than roughly 47 degrees from the Sun, a Venus sign is always the same as the Sun sign or within two signs of it, so only five of the twelve signs are ever possible for a given birthday. Time spent in a sign varies from about 23 days when Venus moves fast to more than four months when a retrograde loop keeps it in place. The formula used here, mean longitude equal to 181.98 plus 58517.82 times T where T counts Julian centuries from the J2000 epoch, is a linear mean element of the kind published in low-precision ephemeris tables. Two caveats follow. It yields a mean heliocentric longitude rather than the geocentric apparent longitude an astrologer reads from an ephemeris, and it ignores the equation of center, worth up to about 0.8 degrees given Venus's orbital eccentricity of 0.0068. For a birth within a day or two of a sign boundary, the result should be checked against a real ephemeris using birth time and time zone. The dignity labels reported, domicile in Taurus and Libra, exaltation in Pisces, detriment in Aries and Scorpio, fall in Virgo, are conventions of the tradition and carry no astronomical meaning.

Venus is the best documented planet in the ancient record. The Venus Tablet of Ammisaduqa, preserved in a seventh century BCE Assyrian copy but recording observations from roughly the seventeenth century BCE, lists heliacal risings and settings of Venus across 21 years and is the oldest surviving planetary record of its kind. Babylonian scribes worked out that five synodic cycles of Venus fill almost exactly eight years, 2,920 days against 2,922, the relation that produces the five-pointed pattern Venus traces against the zodiac over that span. Assigning Venus to love, beauty, and the terms of attraction is Hellenistic. In the Greek astrology compiled at Alexandria and codified by Ptolemy in the second century CE, Venus is the lesser benefic, ruler of Taurus and Libra and exalted in Pisces, signifying marriage, ornament, and pleasure. That scheme passed through Arabic and Latin transmission into Renaissance and modern Western practice largely intact. What changed in the twentieth century was access: inexpensive printed ephemerides, and then computers, let ordinary readers look up a Venus placement that had previously required a professional or laborious hand calculation. The one-line numerical shortcut used here descends from the low-precision planetary formulas published for amateur astronomy and small computers late in that century, where a fraction of a degree of error was an acceptable trade for arithmetic that fits on a single line.