A public calculation contract for Regu tools: what each calculator receives, what it computes, which choices can change the result, and where interpretation begins.
Implementation contract reviewed:
Calculation and interpretation are separate layers
Calculation turns dates, local times, coordinates, time-zone offsets and explicit technique settings into positions, houses, aspects or timing periods.
Interpretation explains symbolic patterns in those outputs. It does not change the calculated positions and is never presented as a guarantee, diagnosis or professional advice.
When birth time is unknown, Regu either blocks a time-dependent technique or clearly treats angles, houses and other time-sensitive outputs as estimates.
Shared input and calculation pipeline
The exact technique changes by tool, but the website follows the same evidence order.
1. Preserve the user’s local record
Date, clock time and selected city stay distinct from UTC. Coordinates identify the place attached to that record.
2. Resolve the historical offset
The website requests the UTC and daylight-saving offset for the coordinates and timestamp. If that lookup cannot be reached, the interface uses its explicit local fallback rather than silently inventing a city.
3. Apply the selected technique
The tool sends normalized inputs and the supported house-system choice to its calculation contract, or runs the published timing rules locally where stated below.
4. Keep raw results distinct from reading copy
Positions, dates, houses and aspects are calculation output. Explanatory text is a separate editorial layer with stated limits.
Five calculation contracts currently documented in depth
These are the exact high-interest tools covered by this review. Other calculators will be added to this page only after their active request and result contracts are traced in the same way.
Annual Profections
Exact calculation
The target birthday year advances the natal Ascendant one whole-sign house per completed year of life. Regu reports the activated house, its traditional ruler as time lord, and the monthly profection sequence beginning on that birthday.
Required inputs and precision
Birth date, local birth time, birth place and target year. The place and historical UTC offset are used to resolve the natal chart; the Ascendant makes birth-time precision important.
Non-personal example
At age 24 the sequence returns to the 1st house; at age 25 it advances to the 2nd. The ruler of the activated sign is shown as the time lord.
What the result contains
Age and cycle, activated whole-sign house and sign, time lord, natal ruler position, activated natal planets and twelve monthly periods.
What it does not claim
This is a timing framework, not an event prediction. An estimated birth time can change the Ascendant and therefore the complete house sequence.
Regu calculates the selected Hermetic Lot from a timed tropical natal chart, then releases from its sign using the traditional sign-period values. L1–L4 are the standard display; L5 is an optional micro-timing layer. Durations use 360-day years and 30-day months.
Required inputs and precision
Exact birth date, local time and place, plus the selected Lot. Time and place determine the Ascendant, sect and Lots, so unknown-time calculation is not offered.
Non-personal example
A Capricorn L1 period carries the traditional value of 27 years. Its L2 sequence begins from Capricorn and distributes the same sign values at the next scale.
What the result contains
Active L1–L4 path, period dates and rulers, peak periods, angular build-up/follow-through, loosing-of-the-bond markers and optional L5 dates.
What it does not claim
Period labels organize symbolic timing; they do not guarantee concrete events. Small date differences can also result when another implementation uses different year-length or Lot conventions.
Regu finds the moment in the selected month when the transiting Moon returns to its natal zodiac longitude, then casts a chart for that moment at the chosen return location. Houses use the selected Placidus or Whole Sign system.
Required inputs and precision
Birth date, local birth time and place, target month, return location and house system. Birth time refines the natal Moon; return location changes angles and houses.
Non-personal example
If the natal Moon is at 12°34′ Taurus, the return is the instant the transiting Moon again reaches that longitude. Moving the return city does not change the return instant, but can change the Ascendant and houses.
What the result contains
Exact return moment, wheel, planets, houses, aspects inside the return chart and contacts back to the natal chart.
What it does not claim
The chart describes a short symbolic cycle, not a guaranteed monthly outcome. With uncertain birth time, the return moment, angles and house emphasis should be treated as provisional.
Regu uses the midpoint composite method: each corresponding pair of natal points is converted to its zodiac midpoint and assembled into a separate relationship chart. Houses use the selected Placidus or Whole Sign system.
Required inputs and precision
Two birth dates and places, both local birth times when available, and a house system. Unknown times can be entered, but time-sensitive points are then estimates.
Non-personal example
If one Sun is at 10° Aries and the other at 10° Gemini, their short-arc midpoint is 10° Taurus. The same midpoint rule is applied to corresponding chart points.
What the result contains
Composite planets, angles, houses, aspects, house emphasis and a relationship-chart wheel.
What it does not claim
A composite chart is a symbolic midpoint construction. It is not a chart for a physical event and cannot prove compatibility, reciprocity, health or permanence.
Regu takes the midpoint between the two UTC birth moments, rounds it to the nearest minute, averages latitude and uses the short-arc midpoint of longitude. It then calculates a real chart for that derived moment and place with Placidus or Whole Sign houses.
Required inputs and precision
Two exact birth dates, local times and places, plus a house system. The tool does not accept unknown birth times because both the midpoint moment and midpoint place depend on precise records.
Non-personal example
Birth moments at 10:00 UTC and 14:00 UTC produce a 12:00 UTC midpoint moment. The result page shows the derived UTC time and midpoint coordinates before the chart.
What the result contains
Derived relationship moment and location, chart wheel, planets, angles, houses, aspects and element balance.
What it does not claim
The midpoint moment is mathematically derived; it is not an observed relationship event. The chart cannot verify relationship quality, consent, compatibility or future outcomes.
Regu does not currently claim that these five contracts have been independently reviewed by a named external astrologer or software auditor.
The implementation contract was traced against the active website request, result and local calculation code on August 26, 2026. This page makes the method reproducible so an outside reviewer can compare like with like; a future review will be named and linked only after it actually occurs.
Public reviewer checklist
Record the exact local date, time, coordinates, target date and house system used in both tools.
Confirm the same zodiac, Lot formula, year length, node choice and unknown-time policy before comparing numbers.
Compare numeric output first: return moment, longitude, house cusp, midpoint or period boundary. Review interpretation separately.
Report the tested URL, inputs, expected value, observed value, difference and comparison source so the issue can be reproduced.
Time-zone reference boundary
Regu’s current website lookup requests location- and timestamp-specific UTC and daylight-saving offsets from Google Maps Platform. IANA is linked as the general public reference for the civil-time history that software ecosystems maintain. Neither source supplies astrological interpretation.
A method description should change when the active calculation changes, not when marketing copy changes. Send a reproducible discrepancy through the contact page; Regu will separate calculation errors, display errors and interpretation disagreements in the review.
