Geocentric positions of bodies on the ecliptic, computed for a specific date, time and place.
Ecliptic
The apparent yearly path of the Sun across the sky; the reference plane along which ecliptic longitudes are measured.
Zodiac sign
Twelve 30° sections of the ecliptic (Aries–Pisces), measured from the vernal point.
Zodiac (tropical / sidereal)
Tropical measures longitude from the vernal point (equinox), sidereal relative to the fixed stars; they differ by precession (ayanamsha).
Planets
Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto. The Sun and Moon are astronomically luminaries, but astrology counts them among the “planets”.
Houses
Division of the local sky into 12 sectors based on Earth's rotation (depends on time and place). Systems: Placidus, Koch, Regiomontanus, Campanus, Topocentric, Equal House, Whole Sign.
Ascendant (ASC)
The intersection of the ecliptic and the local horizon in the east — the point of the ecliptic rising at the given time and place.
MC (Midheaven)
The intersection of the ecliptic with the local meridian — the highest point of its arc above the horizon.
Aspect
The angular distance between two bodies along the ecliptic (conjunction 0°, sextile 60°, square 90°, trine 120°, opposition 180°, and others).
Orb
The allowed deviation from the exact aspect angle; a smaller orb means a more exact aspect.
Lunar nodes
The intersections of the Moon's orbit with the ecliptic — the North (ascending) and South (descending) node. The true node is the instantaneous position, the mean node is smoothed.
Lilith (Black Moon)
The mean lunar apogee — the farthest point of the Moon's orbit from Earth (a computed point, not a physical body).
Chiron
A small body (centaur) orbiting mostly between Saturn and Uranus.
Fixed stars
Bright stars (e.g. Regulus, Spica) projected onto the ecliptic; their longitude shifts with precession.
Retrograde motion (℞)
The apparent backward motion of a body as seen from Earth, due to differing orbital speeds.
Transit
The current positions of bodies compared with the positions in the natal chart.
Synastry
Comparison of the positions and mutual angles of two charts.
Solar return
The moment the Sun returns exactly to its natal ecliptic longitude (around the birthday).
Ephemerides
Tables of precise body positions over time; here NASA/JPL DE440 (Chebyshev polynomials).
ΔT and UT
Local civil time is converted to Universal Time (UT); ΔT is the difference between Terrestrial (ephemeris) time and UT.