METHOD
How we calculate
Every chart on AstroScroll is calculated astronomically, never estimated. This page describes exactly how, so you can check it.
Free to quote, please link this page. · Last calculated: October 5, 2026
Inputs
Date of birth, time of birth and place of birth. You choose the place from a list provided by Google Maps; we store its name and coordinates.
Time zone of the birth place
The time zone is determined from the coordinates of the birth place (tz-lookup). Your local birth time is converted to Universal Time with that zone's historical rules, including daylight saving time (luxon, IANA time zone database). If a local time occurred twice because the clocks went back, we use the first occurrence; if it did not exist because the clocks went forward, we use the offset before the change.
Calculation library
Positions are calculated with astronomy-engine (version 2.1.19): geocentric, apparent positions (light travel time and aberration included), on the ecliptic of date. They are tested against reference data from Swiss Ephemeris, which is widely used in astrology software.
Zodiac, points and houses
We use the tropical zodiac, the one Western astrology is based on.
Calculated points: Sun, Moon, Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto, the North Node (mean node), and with a birth time the Ascendant and the Midheaven (MC).
House system: Placidus. Where Placidus is not defined (very high latitudes), Porphyry is used and the chart notes it.
A planet counts as retrograde when its longitude one hour later is smaller than one hour earlier.
Aspects and orbs
Conjunction 0° (orb 8°), opposition 180° (orb 8°), square 90° (orb 6°), trine 120° (orb 6°), sextile 60° (orb 4°).
Without a birth time
Positions are calculated for 12:00 noon local time. The Ascendant, the Midheaven and the houses are left out, and so are aspects to them. If the Moon changes sign on that day, the chart says so.
How degrees are shown
Degrees show the completed whole degree in the sign; minutes are rounded (60 minutes carry over to the next degree). On the data pages the degree is the completed whole degree as well. All times on the data pages are in Universal Time (UT) and can fall on a different calendar day where you live.
How the eclipses were checked
Eclipse dates and types come from astronomy-engine (time of greatest eclipse). Every eclipse from 2026 to 2030 was compared with the NASA Five Millennium Canon of Solar and Lunar Eclipses; date and type match for all 24.
What a reading is and what it is not
AstroScroll was developed with professional astrologers. Your chart is calculated astronomically, and your reading is written for it with the help of modern technology, following the method astrologers use to read a chart.
Every reading is reviewed by our astrologers and supplemented, corrected and proofread by hand before it is sent.
Astrology is a tool for self-reflection, not a science, and it does not replace medical, psychological, legal or financial advice.
For self-reflection and entertainment. Not medical, psychological, legal or financial advice.
The data in your PDF
At the end of every reading there is a technical appendix with all calculated positions (sign, degree and minute, house, retrograde), the house cusps and the aspects with their orbs.