A–Z reference
The working vocabulary of astrology, defined.
Short reference entries on the technical terms that appear in Astrolium and across the tradition. Each one cross-links to the relevant calculator and the long-form guide.
A
Annual profections
Annual profections advance one house per year, activating a Time Lord planet. Astrolium calculates yours and names the time-lord in under a second.
Astrocartography
Astrocartography maps natal chart angles onto a world map, showing where each planet rises, sets, or culminates. Astrolium renders the 40-line map per chart.
C
E
F
H
Horary astrology
Horary astrology answers a question using a chart cast for the moment it is received. Astrolium applies Lilly's house rules and dignity scores to every chart.
House systems
House systems divide the sky into 12 sectors. Astrolium ships 23 systems including Placidus, whole sign, Koch, and Regiomontanus, all switchable per chart.
L
M
N
P
Part of Fortune
Astrolium explains the Part of Fortune: its Hellenistic origins, the sect-based day/night formula, and what house and sign placement tells a practitioner.
Placidus
Placidus houses divide the chart by the time each degree takes to rise. Astrolium ships Placidus alongside 22 other systems — switch in one click per chart.
Planetary hours
Astrolium explains planetary hours: how the Chaldean order assigns a planet to each unequal hour of the day, and how electional astrologers use them for timing.
Progressed chart
A progressed chart moves the natal chart one day per year of life. Astrolium shows secondary progressions and solar arc directions side by side for any date.
S
Saturn return
Saturn return happens at age 27-30, 57-60, and 86-89 when Saturn completes its orbit. Learn what it means and how Astrolium calculates your exact dates.
Sect
Astrolium explains sect in astrology: the diurnal/nocturnal division that determines which planets are 'in favor' in a chart and how it affects delineation.
Solar arc directions
Solar arc directions move every planet by the arc the Sun travels since birth, about 1 degree per year. Astrolium overlays them on the predictive timeline.
Solar return
A solar return chart maps the sky at the exact moment the Sun returns to its natal degree each year. Learn how to read one with Astrolium's birthday chart tool.
Synastry
Synastry overlays two birth charts to map 14+ cross-aspects between partners. Learn what synastry reveals and how to run a synastry reading with Astrolium.
W
Z
Run the technique, not just look up the term.
Astrolium computes profections, ZR, transits, returns, fixed-star contacts on the same chart in under 300 ms.