About Astrodamus
Astrodamus is a birth chart app and a free astrology library in English and Russian, made by DIGICOM GLOBAL, UAB, a company registered in Lithuania. This page explains who we are, how the charts and calendars are calculated, how the texts are written and how to report a mistake.
Who we are
Astrodamus (astrodamus.net) is owned and run by DIGICOM GLOBAL, UAB, Vilnius, Lithuania (company code 307139863). Write to us at info@astrodamus.net; for questions about your data, privacy@astrodamus.net. Legal details are in the Terms of Use and the Privacy Policy.
What Astrodamus is
Astrodamus builds a natal chart in the browser on phones and computers and explains it in plain language: the wheel, planets, houses and aspects, a reading of the whole chart, a personal forecast, reports and professional techniques for working astrologers. The chart itself is free; paid plans add longer forecasts, reports and the Pro toolkit.
The site also has a free astrology library: aspects, planets in signs, houses, Mercury retrograde and eclipse dates, and calculators for compatibility, the rising sign and the solar return.
How we calculate
- Ephemeris. Positions of the Sun, Moon, planets, lunar nodes and other points come from the Swiss Ephemeris by Astrodienst, which is built on NASA JPL planetary ephemerides. Your chart is calculated on your own device, in the browser.
- Zodiac and houses. By default: tropical zodiac, Placidus houses, true lunar node and mean Lilith. Calculation settings offer 13 house systems (Placidus, Koch, Regiomontanus, Campanus, Porphyry, equal from the ASC or the MC, whole sign, Topocentric, Alcabitius, Morinus, Meridian and Krusinski) and a sidereal zodiac with eight ayanamsas. Above the polar circle, where Placidus and Koch can't be built, the chart falls back to equal houses from the MC and says so.
- Time zones. The birth time is converted to Universal Time with the IANA time zone database, including the daylight saving rules of the birth year. For births before 1993 in the former USSR and Eastern Europe, where IANA data is incomplete, the app checks its own table of regional historical zones, compiled from the decrees on standard and summer time and from regional references. When it corrects the offset it shows a warning marked "documented" or "probable". You can always set the offset by hand (time zones).
- Calendars on this site. English pages give times in US Eastern Time (New York) with UTC in brackets; Russian pages are calculated for Moscow in Moscow time (UTC+3). Lunar days are counted from the new moon and then from each moonrise. A retrograde period runs from the station retrograde to the station direct. The pages are rebuilt every night, so the "today" blocks stay current.
- Accuracy. Automated checks run on every change to the app: reference charts, and individual methods against published values from NASA, JPL Horizons and Astronomy Engine. The lunar calendar is cross-checked with Astronomy Engine: phases agree within 2 minutes and moonrises within 3 minutes. A chart is only as accurate as the birth data: on average, four minutes of birth time move the Ascendant by about one degree.
Sources and standards
- Major aspects: conjunction, sextile, square, trine and opposition. Default orbs depend on the planet pair.
- Classical dignities: domicile and exaltation, Dorothean triplicities, Egyptian terms and Chaldean faces as in William Lilly's Christian Astrology (1647), with Lilly's scores (dignities).
- Traditional techniques follow the classical sources named on their help pages, for example Ptolemy's Tetrabiblos for the hyleg.
- Best days for activities rate the Moon's sign, lunar day, phase, void-of-course Moon and lunar aspects by the rules of the traditional lunar calendar (how best days are chosen).
How the texts are written
The reference articles on this site and the interpretation texts in the app are original texts written for Astrodamus by the Astrodamus editorial team, in English and Russian. They are reviewed for consistency with classical rules: the nature of the planets, signs and houses, the meaning of each aspect and the dignities above. Astronomical facts and the dates in tables come from the calculation, not from the text.
Astrology here is a language for reflection, not a prediction of events. The texts describe tendencies and themes, and decisions stay yours. Nothing on Astrodamus is medical, legal, financial or psychological advice.
Editorial policy and corrections
Each page shows the date of its last significant change: a new or corrected text, new data or new links. Design changes don't move the date. Pages with calculated tables are rebuilt every night, and their date changes when the data on them changes.
Found a mistake in a calculation or a text? Write to info@astrodamus.net with a link to the page. We check calculations against the engine and an independent source, fix confirmed errors and update the page date.