The following graphs show intonation measurements of guitar fretboards. For each fret, the deviation from the equal tempered scale is shown in cents. The first data set is for a Les Paul Special with a fixed adjustment tailpiece (original). The second set is for a different Les Paul Special with an adjustable tailpiece. The third data set is for a Stratocaster (notice the high E string could use some intonation adjustment).












These measurements were done using a Precision Strobe Tuner. The deviation for each note was measured by adjusting the calibration vernier knob until the display rotation was stopped. The deviation was read from the calibration setting display. Great care must be taken to stabilize the guitar while each string is measured. Things like a furnace turning on can change the string temperature enough to shift the pitch several cents. The neck must be well supported and the strings should be fretted carefully. Everything affects pitch measureably, furnaces, neck support and fretting technique included. You can change a strings pitch 20 cents by rotating the neck (64 Gibson SG, thin neck) from face up to face down! I expect moon phase has no affect.