How to enter a moon phase series into Excel??

  • Thread starter Thread starter Michael Levin
  • Start date Start date
M

Michael Levin

I'm a biologist working with some circadian rhythm data. I need to be able
to make a chart in excel where the X axis is dates, with correct phases of
the moon for each phase. What is the easiest way to get moon phase series
into an excel sheet?
 
Hi Michael,

For your purposes, you can approximate the phase of the moon using a formula
like:
=COS(RADIANS(360/29.530588*(ROW()-1+n)))
where a starting date at the full moon is on row 1 and 'n' is the expired
proportion of the day when the full moon occurred (eg 1am = 0.041667, 12
noon = 0.5). Then copy down for as many rows as needed. If you chart this
against the dates, you'll see a sine wave, where 1s are full moons -1s are
new moons and 0s are half-moons. If your starting time & date start on a row
other than row 1, change the '1' in the formula to match.

You will note that I said 'approximate'. That is because lunar cycles are
not exactly 29.530588 days each, but only average something close to that
value.

Cheers
 
Back
Top