Day and night charts

Meaning

Every chart is either a day chart or a night chart. If the Sun was above the horizon at the moment the chart is cast, it is a day chart, also called diurnal. If the Sun was below the horizon, it is a night chart, nocturnal.

In a drawn chart the horizon is the line from the Ascendant (on the left) to the Descendant (on the right). The upper half, houses 7 to 12, is above the horizon; the lower half, houses 1 to 6, is below it. So the quickest test is: is the Sun in the top half of the wheel? If yes, it is a day chart.

This is not the same as asking whether it was light outside. At dawn the sky is bright before the Sun rises, and at dusk it stays bright after sunset. Astrologers use the Sun's actual position relative to the horizon, not the brightness of the sky.

Origin and history

The distinction is as old as the doctrine of sect itself. In Greek the planets' two parties are the hairesis of day and of night, and a nativity was described as belonging to one or the other. Ptolemy grounds the division in the nature of day and night: day warmer and more active, night moister and more passive [1].

Dorotheus shows how much depended on it. For each element he names a day lord and a night lord of the triplicity, and which one leads depends on the time of birth [2]. Many Hellenistic techniques ask the same question first: is the chart diurnal or nocturnal? The answer decides which luminary leads the chart, which benefic and malefic are most important, and how certain lots are calculated [3].

The Arabic authors kept the division and added finer conditions that depend on it, such as halb and hayz [4]. Lilly still distinguishes day and night: his example of reception by triplicity holds only if the question or nativity is by day [5]. Not every technique changed with sect, though: Lilly takes the Part of Fortune in the same way by day and by night [5], where many earlier authors reversed it for night charts [3].

How it is used

Once the sect of the chart is known, each planet can be judged in sect or out of sect, and then more finely for halb and hayz.

On this site the test uses the Ascendant itself, not house numbers. The chart is diurnal when the Sun's zodiacal degree lies in the half of the zodiac between the Descendant and the Ascendant that contains the Midheaven, and nocturnal otherwise. So the house system chosen makes no difference. If the Sun is exactly on the Ascendant or Descendant (within a ten-millionth of a degree), the engine treats the sect as undecidable and does not score dignities for that moment. The day/night status appears at the top of the sect section in each planet's detail.

Where authorities differ.

• Twilight. The sources cited here define day and night by the Sun's position above or below the horizon. Births close to sunrise or sunset are sometimes discussed as borderline cases, but no agreed margin is found in these sources. This site uses the horizon exactly.
• Geometry or appearance? The Sun crossing the Ascendant is the geometric sunrise of its centre. Because of atmospheric refraction and the size of the Sun's disc, the Sun is seen on the horizon a few minutes before that. For almost all charts this makes no difference, but it can matter within a degree or so of sunrise or sunset.
• House systems. Sect depends on the horizon, not on house numbers. In quadrant house systems houses 7–12 are exactly the half above the horizon. In whole-sign houses they are not: a Sun in the rising sign may be a few degrees above the Ascendant (day) or below it (night), so check the Sun against the Ascendant degree itself. This site does that automatically.

Examples

• Noon birth. The Sun is near the Midheaven, the top of the chart. Day chart: Jupiter is the benefic of sect, Mars the most difficult malefic.
• Midnight birth. The Sun is near the bottom of the chart. Night chart: Venus is the benefic of sect, Saturn the most difficult malefic.
• Birth twenty minutes before sunrise. The sky is getting light, but the Sun is still just below the Ascendant, in the first house. Strictly, it is a night chart.
• Birth just after sunset. The Sun has just crossed the Descendant into the sixth house. Night chart, even though it is still light outside.

See also

What the two teams are, and why each malefic is placed where it is, is explained in sect.