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Reviewed Lunar Phase-Longitude Record

Reconcile one source-owned apparent Moon/Sun ecliptic-longitude row without inventing a current ephemeris, next phase time, illuminated percentage, tide or activity recommendation.

Use this result well

Inputs that matter
One named reviewed lunar phase-longitude record and revision; exact coordinate source and responsible reviewer; one canonical ISO8601 UTC source instant; one explicit apparent ecliptic reference/equinox/ecliptic convention; same-row apparent Moon and Sun ecliptic longitudes; source phase designation as intermediate or one named primary event; a narrow reviewer-owned primary-event coordinate residual; optional same-instant/same-reference reported longitude excess with its independent source and absolute reconciliation tolerance; and explicit current/next-event, illumination, local rise/visibility/tide and photography/fishing/gardening/safety boundaries
Output to expect
Normalized Moon-minus-Sun apparent ecliptic-longitude excess; traditional crescent/gibbous or exact-coordinate sector; nearest 0°/90°/180°/270° primary-phase target and signed reproduced-minus-target offset; optional source-declared primary-event coordinate residual; optional reported-minus-reproduced longitude difference inside tolerance; complete source/time/frame evidence; deliberate page-session retention, copy/Markdown/print/share actions; and stable Project outputs that keep current/next ephemeris, illuminated fraction, local rise/set/visibility/weather/tide and activity/safety approval false
How it works
Normalize each accepted 0° through360° source longitude to 0° through<360°, compute D = normalize(apparent Moon longitude − apparent Sun longitude), classify only the traditional phase sector, circularly compare D with the nearest and any source-declared USNO primary target, and optionally circularly compare one same-basis independent report inside reviewer-owned tolerances without moving or generating an event time
  • The exact UTC instant, source response, apparent ecliptic reference, equinox/ecliptic convention, precision and both longitudes must travel together. Another instant, geocentric/topocentric or apparent/geometric reference, source revision or report basis needs another record; average lunar age is never substituted for an ephemeris.
  • Coordinate agreement is not ephemeris certification or a current/next event service. Keep source-published event time, illuminated fraction, orientation, moonrise/transit/moonset, crescent visibility, local horizon/weather/moonlight, station tide/current, photography/exposure/target, fishing/catch, gardening/agronomy, travel, regulation and safety decisions with their responsible current evidence.

Choose your path

Built around the job you need to finish

Reconcile one exact source-owned apparent Moon/Sun ecliptic-longitude row into a normalized lunar phase-longitude record without generating a current ephemeris, next event, illuminated percentage, local condition or activity recommendation.

Beginner transcribing one retained phase row

Understand the traditional phase sector without being given a fabricated live moon calendar or unexplained illumination estimate.

Load one source-owned Moon140°/Sun0° row, confirm its exact UTC instant, source response and apparent ecliptic reference, then explicitly reconcile.

Gets140° Moon-minus-Sun excess, a waxing-gibbous sector and−40° reproduced-minus-Full-Moon-target offset while current/next phase time and illuminated percentage remain explicitly ungenerated.

Astronomy-club reviewer checking a Full Moon event row

Catch transcription or frame mismatches without using a coordinate tolerance as an event-time or ephemeris-accuracy certificate.

Load the source-declared Full Moon row that reproduces180°, retain an independent same-instant/same-reference180.05° report and use separate0.1° event-residual and report tolerances.

Gets a zero declared-event residual and signed+0.05° reported-minus-reproduced difference inside tolerance; a mismatched event or report fails at its own field and never moves the event time.

Planner testing downstream consequence boundaries

Prevent one coordinate row from claiming a current/next event, illumination, local sky/tide or photography/fishing/gardening/safety outcome.

Reconcile the supported row, then exercise each unsupported select before restoring the supported external-review boundary.

Every unsupported request removes the current result/actions, focuses the exact owning select with a complete refusal and requires explicit reconciliation before arithmetic returns.

Authoritative checks for this tool

Outputs and checklists are planning aids. Review the linked current authorities and the records, terms, instructions, and requirements that apply to your exact situation before a consequential decision.

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Reference & details

How it works

Freeze One Source Row

Retain one exact UTC instant, source response/revision, responsible reviewer and apparent ecliptic reference. Moon and Sun longitudes must share the same equinox/ecliptic convention and precision; another instant or frame needs another record.

same source + same UTC instant + same apparent ecliptic reference

Reproduce Phase Longitude

Normalize apparent Moon longitude minus apparent Sun longitude to 0° through less than 360°. USNO defines the four primary phases at excess longitudes 0°, 90°, 180° and 270°; values between them are traditional crescent or gibbous sectors.

D = normalize(λMoon − λSun, 0° ≤ D < 360°)

Reconcile, Do Not Generate

A source-declared primary event is checked only against its entered coordinate target and reviewer-owned residual. An optional independent longitude-excess report must use the same instant and reference. Neither tolerance generates or moves an event time, proves ephemeris accuracy or approves downstream use.

signed difference = circular(reported − reproduced); |difference| ≤ entered tolerance

Updated: August 2026

Example Scenarios

Load the retained Moon 140° / Sun 0° row, confirm its exact UTC/source/frame evidence and reconcile. The result is a 140° waxing-gibbous sector with a −40° offset from the 180° Full Moon target—not a live sky or event forecast.

A same-source event row reproduces 180°. An independent same-instant report says 180.05° and the reviewer enters a 0.1° absolute tolerance. The signed +0.05° difference passes while the authoritative event time stays with the source.

Selecting current/next phase generation, illuminated-percentage derivation, local visibility/tide or photography/fishing/gardening advice removes the current result, focuses the owning field and explains the responsible external evidence required.

Common Mistakes to Avoid

Using days since an assumed New Moon as an exact current ephemeris

Retain the exact same-instant apparent Moon/Sun longitude row from a responsible source. An average lunation shortcut cannot establish the current or next event.

Mixing Moon and Sun longitudes from different instants or reference conventions

Keep both values with one UTC instant, apparent ecliptic reference, equinox/ecliptic convention, source response and precision.

Treating a coordinate tolerance as an event-time, visibility, tide or activity approval

The tolerance checks only same-basis arithmetic. Keep event publication, illuminated fraction, local sky, station tide, equipment, habitat, agronomy and safety decisions with their responsible sources.

FAQ

Only the normalized apparent Moon-minus-Sun ecliptic-longitude excess from one entered same-source row, its traditional sector, nearest primary target, source-declared event residual and optional same-basis report difference.

No. It confirms coordinate arithmetic for the entered source instant. An exact primary-phase event time remains the source's responsibility; this Tool does not search, interpolate or advance time.

USNO treats illuminated fraction as a separate quantitative source record with its own exact time and observer reference. Use the Lunar Illumination Record Check instead of substituting this phase-longitude arithmetic.

USNO states that practical phase and illuminated percentage are independent of observer location. Orientation, rise/set, horizon clearance and crescent visibility are different location-specific tasks and remain external.

No. Those decisions require their own current equipment, target, station, water, weather, habitat, agronomic, regulatory and safety evidence. A phase-longitude row does not approve them.

About Reviewed Lunar Phase-Longitude Record

This reviewed record reproduces the normalized excess of one source-owned apparent Moon ecliptic longitude over the same-row apparent Sun longitude. It names the traditional phase sector, identifies the nearest 0°/90°/180°/270° primary-phase target, checks a source-declared primary event inside a narrow coordinate residual, and optionally reconciles one same-basis report. It does not generate an ephemeris, event time, illuminated percentage, rise/set, visibility, tide or use decision.