Moon Age Days From Elongation

Uniform synodic phase-clock age from ORIENTED 0..360 elongation and independent period; sky separation 0..180 alone cannot distinguish waxing/waning. Model only, not an ephemeris, measured stellar identity or observational guarantee.

Description

Elongation can be turned into an age within a uniform synodic-cycle model.

Elongation can be turned into an age within a uniform synodic-cycle model.^[1]

That phase approximation is distinct from the actual time since a specific new moon. Use Moon Age Days From Elongation to evaluate the supplied inputs under the model explained below.

When to use Moon Age Days From Elongation

Use Moon Age Days From Elongation to evaluate the supplied inputs under the model explained below. Establish the units, measurement scope and model assumptions before entering values.

How to use Moon Age Days From Elongation and understand its results

Establish the units, measurement scope and model assumptions before entering values.
Enter Oriented synodic elongation degrees, Caller synodic period days using the field table and validation rules below, then run the tool.
Read Uniform phase age days; interpret the units, signs, ordering and unknown-value placeholders described below.
Correct reported input errors and rerun. Apply successful results according to their specific meanings and check the assumptions before using them in a decision.

Input field	Meaning	Value type	Requirement
orientedSynodicElongationDegrees	Oriented synodic elongation degrees	number	Required; constraints below
callerSynodicPeriodDays	Caller synodic period days	number	Required; constraints below

Enter finite oriented synodic elongation in degrees and a positive caller period in days. Wrap elongation to [0,360), divide by 360 and multiply by the period. A full-turn input returns zero. No actual new-moon epoch or variable orbital speed is used.

uniformPhaseAgeDays=wrap360(elongation)/360×callerPeriodDays

Use the field order, units and branch conditions described above.

Output field	Meaning	Value type
uniformPhaseAgeDays	Uniform phase age days	number

json

{
  "input": {
    "orientedSynodicElongationDegrees": 180,
    "callerSynodicPeriodDays": 29.530588853
  },
  "output": {
    "uniformPhaseAgeDays": 14.7652944265
  }
}

Limitations and assumptions

That phase approximation is distinct from the actual time since a specific new moon. Apply the exact scope and assumptions explained above.

All listed fields require explicit values. Unexpected fields, incorrect types, nonfinite numbers and sparse arrays fail validation. Domain-specific bounds, alignments and supported tokens are explained above; extremely large inputs or outputs can also be rejected. Input errors differ from successful false results, empty match lists and unknown-evidence placeholders.

Alternative or Complementary methods

Use Saros Cycle Eclipse Repeat Years for a related task: A repeat cycle can be represented by a number of matched synodic months.

Use Lunar Phase Illumination Percent for a related task: Lunar elongation and illuminated fraction are connected under distant-Sun geometry.

References

Moon Age Days From Elongation — tool.io

Similar or alternative tools

Saros Cycle Eclipse Repeat Years
A repeat cycle can be represented by a number of matched synodic months.
Lunar Phase Illumination Percent
Lunar elongation and illuminated fraction are connected under distant-Sun geometry.