Approximately speaking, how many days are in between each phase of the moon?

Question

Meaning, how many days are between the new moon, to the waxing crescent moon. Then to the waxing crescent moon, to the first quarter moon. Then from the first quarter moon, to the waxing gibbous moon, etc. So only between two phases, not all of them. Are the days all relatively the same, or do they differ at all?

Answer 1

Well, technically, the moon is always in "some" phase.  Our definitions of crescent and gibbous are just what well call it when it is not precisely New, First Quarter, Full, or Third Quarter.  The instant a "new moon" has rotated enough to establish a visible crescent, no matter how thin it is, it is in "waxing crescent" until it reaches first quarter.  Then it is in "waxing gibbous" until it is full.  Then reverse the process for "waning gibbous" to "third quarter" and "waning crescent" to new moon.

The time between New-1st, 1st to Full, Full to 3rd, and 3rd to New are all approximately one week (slightly more than that, to account for the 29.5 days vs. a four week span being only 28 days).  But it is ALWAYS in some phase.  Crescent and Gibbous are just defined by the moon not appearing to us as "unlit," "half-lit," or "fully lit."

Answer 2

Each lunar cycle lasts 29.53 days.

To be more exact. The moon makes a complete orbit of the earth in  27.3 days. This is called the sidereal period.

However since the earth is moving in its orbit around the sun, it looks like it takes the moon a little longer to complete its orbit. That will be 29.5 days and it is called the synodic period.

Since the orbit is circular, each 'subperiod' (there are 8 ranging from new moon to waning crescent moon) will last 1/8 of the total cycle.

Answer 3

"The time between two full moons (and between successive occurrences of the same phase) is about 29.53 days (29 days, 12 hours, 44 minutes) on average." [http://en.wikipedia.org/wiki/Lunar_phase...  It's that "on average" that's the kicker.  Apparently they're not all the same (I thought they were, till I looked it up myself):

The actual moon phases this upcoming month actually happen at:

New: 30 Aug 2008, 7:59pm Greenwich Mean Time (GMT)

First Quarter: 7 Sept 2008, 2:05pm GMT (7 days, 18 hours, 6 minutes, or 7.754 days since the last phase)

Full: 15 Sept 2008, 9:14am GMT (7 days, 19 hours, 9 minutes, or 7.798 days)

Third Quarter: 22 Sept 2008, 5:05am GMT (6 days, 19 hours, 51 minutes, or 6.827 days)

New Moon; 29 Sept 2008, 8:13am GMT (7 days, 3 hours, 8 minutes, or 7.131 days)

But if you're looking for an approximate, you could likely just use 7.38 (that's the average 29.53 days from above, divided by 4).

But the waxing and waning crescent and gibbous moons do not happen at one moment in time.  See the chart here: http://en.wikipedia.org/wiki/Lunar_phase... .  Those are just what we call the moon in between the new moon, the first quarter, the full moon, and the third quarter.  So there's no amount of time between the new moon and the waxing crescent moon, for example; the change is instantaneous -- once the moon is not new, it is a waxing crescent.  

Answer 4

I was brought up in my system (in India) as per which each day's phase has a name, Starting from new moon thorugh fullmoon till the next new moon there are 30 phases. Transition between successive phases is not jerky but imperciptibly smooth.