Frequency Atlas

Moon Apsides Rotation (Cosmic Octave)

246.04 Hz

Nearest note: B3, 6 cents below standard tuning

A tone calculated from a measured cycle, by doubling its frequency 36 times. It is calculated, not recorded.

How well is this supported?

DerivedOctave of an astronomical cycle

Calculated from a measured value by a stated method. You can check the arithmetic. What the result means is a matter of interpretation.

The cycle is measured. The tone is calculated from it by doubling, so that it can be heard. Nothing in space makes this sound.

What the four labels meanChecked against sources September 27, 2026

The button plays a plain tone. Start with the volume low. Phone and laptop speakers play low notes quietly; headphones or a speaker help.

Where this number comes from

The nearest and farthest points of the Moon from the Earth drift around its orbit once in about 8.85 years. 1 ÷ 279,304,020 seconds, doubled 36 times, is 246.04 Hz. That is a B, about 6 cents below standard tuning.

  1. Step 1. Start with the length of the cycle

    Apogee and perigee moving through the ecliptic: 3,232 days, 16 hours, 27 minutes.

  2. Step 2. Turn it into a frequency

    One divided by that many seconds is 3.58 × 10⁻⁹ Hz. That is far too slow to hear.

  3. Step 3. Double it 36 times

    Doubling a frequency raises it by one octave: the same note, higher. After 36 doublings it is 246.04 Hz.

  4. Step 4. Name the note

    246.04 Hz is a B, 6 cents below standard tuning. A cent is one hundredth of the step between two neighboring piano keys. To play in tune with this tone, an instrument sets its A to 438.39 Hz instead of 440.

  5. Step 5. Keep doubling and the number lands in the range of light

    41 more doublings give the frequency of light with a wavelength of 554 nm, which is yellow-green. This is arithmetic. It pairs a tone with a color; it does not show that the two are connected.

The method is Hans Cousto’s. Planet gongs explained walks through it and says what it does and does not show.

Facts

Frequency
246.04 Hz
One cycle takes
8.85 years
Wavelength in air (20 °C)
1.39 m
Nearest note
B3, 6 cents below standard tuning
Kind of statement
Octave of an astronomical cycle
Filed under
Earth, Moon & Sun

Tuning Data

The row for this tone in Hans Cousto’s tables, with the tempo and pendulum length that follow from it.

Cycle
Apogee and perigee moving through the ecliptic
Length of the cycle
3,232 days, 16 hours, 27 minutes
Octaves up
36
Concert pitch (A)
438.39 Hz
Difference from A = 440 Hz
-6.34 cents
Tempo
115.33 beats per minute
Pendulum length
6.7 cm / 2.65 in
Color by octave
Yellow-Green (554 nm)
Tempo and pendulum length, octave by octave
OctaveFrequencyOne cycleTempoPendulum
29tempo1.92 Hz520.24 ms115.33 BPM6.7 cm
303.84 Hz260.12 ms230.66 BPM1.7 cm
317.69 Hz130.06 msToo fast to countToo short to build
3215.38 Hz65.03 msToo fast to countToo short to build
3330.76 Hz32.52 msToo fast to countToo short to build
3461.51 Hz16.26 msToo fast to countToo short to build
35123.02 Hz8.13 msToo fast to countToo short to build
36tone246.04 Hz4.06 msToo fast to countToo short to build
Intervals built on this tone
RatioIntervalFrequencyNoteConcert ACents from 440
1/1Perfect unison246.04 HzB3438.39 Hz-6.33
81/80Syntonic comma249.12 HzB3443.87 Hz+15.17
531441/524288Pythagorean comma249.40 HzB3444.37 Hz+17.13
128/125Diesis251.94 HzB3448.91 Hz+34.73
648/625Greater diesis255.09 HzC4429.02 Hz-43.77
25/24Chroma256.29 HzC4431.03 Hz-35.66
16/15Diatonic semitone262.44 HzC4441.37 Hz+5.40
10/9Minor whole tone273.38 HzC#4433.96 Hz-23.93
9/8Major whole tone276.80 HzC#4439.38 Hz-2.42
8/7Septimal whole tone281.19 HzC#4446.36 Hz+24.84
6/5Minor third295.25 HzD4442.37 Hz+9.31
5/4Major third307.55 HzD#4434.94 Hz-20.02
4/3Perfect fourth328.05 HzE4437.90 Hz-8.29
3/2Perfect fifth369.06 HzF#4438.89 Hz-4.38
8/5Minor sixth393.66 HzG4441.87 Hz+7.35
5/3Major sixth410.07 HzG#4434.45 Hz-21.97
7/4Natural seventh430.57 HzA4430.57 Hz-37.51
16/9Pythagorean minor seventh437.40 HzA4437.40 Hz-10.24
9/5Just minor seventh442.87 HzA4442.87 Hz+11.26
15/8Major seventh461.33 HzA#4435.43 Hz-18.06
2/1Octave492.08 HzB4438.39 Hz-6.33

Source notes

The apsidal cycle tracks the rotation of the Moon’s nearest and furthest orbital points relative to the Earth.

Source: Hans Cousto — Tuning Data / Sun Earth Moon Planets. View the source PDF.

License: CC BY-NC-ND 4.0, as stated in Stimmdaten.pdf (German edition), page 2.

Values are reproduced from Cousto’s tables. Tempo, pendulum length and interval tables are calculated by this site from those values.

See every tone in the tables: Open the tuning data reference.

Sources

More about the pitch

The same note in every octave

Each step doubles or halves the frequency. Tap one to hear it.

Entries close in pitch

Within 35 cents of this tone, in any octave. A cent is one hundredth of the step between two neighboring piano keys. Being close in pitch does not mean two things are connected.

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