Since you were interested enough to inquire, I have decided
to pass

along the following to you. This is in regards to the
easterly shift of

the Moon in the sky, along the ecliptic, from one day
to the next,

say if you were to observe the moon at the same clock
time over a

period of a week or so.

If you were to figure how much the moon shifts along the
ecliptic

relative to the background stars then:

shift = 360 degrees / 27.32 days per revolution (with
respect to the

stars) = 13.2 degrees/day, and so the Moon would lie
13.2 degrees

to the east relative to the stars (using the stars along
the ecliptic as

reference points).

On the other hand, if you were to figure out how much
the Moon

shifts relative to a direction along the horizon, that
is with respect to

a *moving *earth, then this is slightly different.
Let's say that at 10 pm

the moon lay on a line connecting your zenith with due
south along

your horizon from your location, and you checked again
at 10 pm

the next night, then that shift would be:

shift = 360 / 29.53 days per lunar month = 12.2 degrees
per day, and

so the moon would lie 12.2 degrees to the east of due
south.

The difference in these shifts is of course due to the
fact that the

Earth revolves around the Sun, about a degree per day,
so that the

stars shift westward by about 1 degree per day.

If you really want to split hairs, there are other complicating
factors

involved as well, but 12 or 13 degrees eastward per day
are good

round numbers and are all anybody need understand in
this class.

Professor Korista