Frequency Atlas

Moon Synodic Month (Cosmic Octave)

210.42 Hz

Nearest note: G♯3, 23 cents above standard tuning

A tone calculated from a measured cycle, by doubling its frequency 29 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 Moon takes 29.530588 days to go from one new moon to the next. 1 ÷ 2,551,443 seconds, doubled 29 times, is 210.42 Hz. That is a G♯, about 23 cents above standard tuning.

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

    Moon orbit from new moon to new moon: 29.530588 days.

  2. Step 2. Turn it into a frequency

    One divided by that many seconds is 3.92 × 10⁻⁷ Hz. That is far too slow to hear.

  3. Step 3. Double it 29 times

    Doubling a frequency raises it by one octave: the same note, higher. After 29 doublings it is 210.42 Hz.

  4. Step 4. Name the note

    210.42 Hz is a G♯, 23 cents above 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 445.86 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 648 nm, which is orange. 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.

What is said about it

What is said, not what was measured

In planetary gong practice this tone is associated with emotion, fluids and cycles.

Facts

Frequency
210.42 Hz
One cycle takes
29.53 days
Wavelength in air (20 °C)
1.63 m
Nearest note
G♯3, 23 cents above 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
Moon orbit from new moon to new moon
Length of the cycle
29.530588 days
Octaves up
29
Concert pitch (A)
445.86 Hz
Difference from A = 440 Hz
+22.91 cents
Tempo
98.63 beats per minute
Pendulum length
9.2 cm / 3.62 in
Color by octave
Orange (648 nm)
Tempo and pendulum length, octave by octave
OctaveFrequencyOne cycleTempoPendulum
22tempo1.64 Hz608.31 ms98.63 BPM9.2 cm
233.29 Hz304.15 ms197.27 BPM2.3 cm
246.58 Hz152.08 msToo fast to countToo short to build
2513.15 Hz76.04 msToo fast to countToo short to build
2626.30 Hz38.02 msToo fast to countToo short to build
2752.61 Hz19.01 msToo fast to countToo short to build
28105.21 Hz9.50 msToo fast to countToo short to build
29tone210.42 Hz4.75 msToo fast to countToo short to build
Intervals built on this tone
RatioIntervalFrequencyNoteConcert ACents from 440
1/1Perfect unison210.42 HzG#3445.86 Hz+22.92
81/80Syntonic comma213.05 HzG#3451.44 Hz+44.43
531441/524288Pythagorean comma213.29 HzG#3451.95 Hz+46.38
128/125Diesis215.47 HzA3430.94 Hz-36.02
648/625Greater diesis218.16 HzA3436.33 Hz-14.51
25/24Chroma219.19 HzA3438.38 Hz-6.41
16/15Diatonic semitone224.45 HzA3448.90 Hz+34.65
10/9Minor whole tone233.80 HzA#3441.36 Hz+5.33
9/8Major whole tone236.72 HzA#3446.87 Hz+26.83
8/7Septimal whole tone240.48 HzB3428.49 Hz-45.90
6/5Minor third252.50 HzB3449.91 Hz+38.56
5/4Major third263.03 HzC4442.35 Hz+9.24
4/3Perfect fourth280.56 HzC#4445.36 Hz+20.97
3/2Perfect fifth315.63 HzD#4446.37 Hz+24.88
8/5Minor sixth336.67 HzE4449.40 Hz+36.61
5/3Major sixth350.70 HzF4441.85 Hz+7.28
7/4Natural seventh368.23 HzF#4437.91 Hz-8.25
16/9Pythagorean minor seventh374.08 HzF#4444.86 Hz+19.01
9/5Just minor seventh378.76 HzF#4450.42 Hz+40.52
15/8Major seventh394.54 HzG4442.85 Hz+11.19
2/1Octave420.84 HzG#4445.86 Hz+22.92

Source notes

The synodic month measures the lunar cycle by the changing relationship between Moon and Sun.

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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