Birth chart settings, explained

Start with one question

Are you creating your first chart, or trying to reproduce a chart from another calculator? For a first chart, use one consistent set of settings and inspect its calculation basis. For a comparison, copy the other calculator’s settings explicitly; a shared label such as ‘birth chart’ does not establish a shared method.

House systems divide the chart differently

Whole sign houses use the Ascendant’s entire zodiac sign as the first house. Equal houses begin at the Ascendant degree and proceed in 30° steps. Quadrant systems subdivide the chart using additional geometry. Sky Degrees supports Alcabitius, Placidus, Koch, Porphyry, Regiomontanus, Campanus, Whole sign and Equal house.

The Ascendant and Midheaven are astronomical angles. They remain separate from house cusps: in whole sign or equal houses, the Midheaven need not be the tenth-house cusp. At extreme latitudes some systems cannot produce a supported result; the calculator reports an error instead of substituting another system.

Tropical, sidereal and ayanamsa

The tropical zodiac measures twelve equal signs from the equinox. A sidereal zodiac offsets those longitudes using an ayanamsa, an angular reference difference. Sky Degrees offers Lahiri and Fagan–Bradley for sidereal charts. Choose the same ayanamsa when comparing results.

These twelve equal zodiac signs are not the irregular astronomical constellation boundaries. A changed sign label may reflect the selected coordinate convention rather than a changed birth record. Neither zodiac setting adds evidence that a symbolic interpretation predicts events.

Aspect orbs determine which connections appear

The five available aspects are conjunction (0°), sextile (60°), square (90°), trine (120°) and opposition (180°). An orb is the allowed distance from the exact angle. Sky Degrees uses planetary moieties: the allowed orb for a pair is the average of the two configured planetary values.

For example, values of 8° and 6° allow a 7° orb for that pair. Reducing them removes wider connections; it does not make the astronomical positions more accurate. Keep the actual separation and orb alongside any interpretation.