Lunar return calendar
Find when the Moon returns to its natal geocentric tropical longitude within a bounded interval. The result is an astronomical time used in a symbolic tradition.
Your inputs
Start with the example values, then replace them with your own. For tables, keep the vertical bar separators and use a dot for decimals.
Select a city to fill coordinates and the IANA time zone, or enter them manually. Verify historical local records; browser time-zone data can differ for old dates.
Astrology is for cultural exploration and entertainment. Do not base health, financial, relationship or major life decisions on these outputs. It has no scientifically established predictive validity.
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Result and workspace
Use the start button to open your result or activity.
How it works
Compute the natal Moon longitude from the known birth instant. Search forward in six-hour steps, bracket continuous longitude crossings, then bisect to one-second resolution. This is numerical resolution, not a claim of one-second observational accuracy. Results are UTC; a return does not predict events.
Worked example
These sample results use the original example inputs in the form. They do not change when you edit your inputs; your own result appears in the workspace.
For the worked example, the birth time is treated as known. Use only a verified birth time for your own calculation.
- Events: 13
| UTC instant | Longitude | Angular separation |
|---|---|---|
| 2026-01-12T11:44:42.751Z | 222.3216 | 0 |
| 2026-02-08T19:43:56.828Z | 222.3216 | 0 |
| 2026-03-08T04:15:09.777Z | 222.3216 | 0 |
| 2026-04-04T12:19:54.763Z | 222.3216 | 0 |
Read the result carefully
Results depend on the values and assumptions shown above. Change one input at a time to see its effect. A blank or unavailable result means the data does not support a calculation; it is not zero.
Astrology is a cultural and entertainment framework, not a scientifically validated way to predict personality, health, relationships or future events. Astronomical positions do not validate astrological interpretations.
Data and calculation sources
Astronomy Engine 2.1.19 (MIT) · GeoNames (CC BY 4.0) · IANA
Geocentric tropical positions use Astronomy Engine. House options are equal and whole-sign only. City coordinates are approximate city centers from GeoNames, downloaded on 6 October 2026. Choose precise coordinates when available. Supported birth years: 1900–2100.