Where is the Moon ?

If you are only interested in finding out where to point your antenna on a cloudy day or night, then skip down to the next section.
But if you want to understand the basics of how the moon moves in the sky, then read on!

The apparent motion of the stars in the sky arises primarily from the earth's rotation, to a lesser extent from the motion of the earth round the sun, and to a minute extent from the "proper" motions of each star in the universe.
The attempts of early astronomers and navigators to understand these motions led to a coordinate system for all heavenly bodies in which the effects of the earth's rotation were removed.
A star's direction is measured by two angles:
1. Its elevation angle above or below a plane through the earth's equator - Declination,
2. Its azimuthal direction relative to an arbitrary direction in space - Right Ascension (RA) and Siderial Hour Angle (SHA).

RA is the celestial equivalent of terrestrial longitude. Its zero point is called the First Point of Aries, which is the place in the sky where the Sun crosses the celestial equator at the March equinox.
RA is measured positive to the east, and may be expressed either in degrees up to 360, or more commonly in units of time (hours, minutes, seconds) up to 24 hours.
SHA is used in navigation and is essentially the same as RA, but is measured positive to the west! This difference arises from a need to make navigation calculations as simple as possible on a pitching boat before the days of GPS.

Declination is the celestial equivalent of latitude, and is measured in degrees (positive to the north).

The sun's declination is therefore zero on about March 21, +23.5 deg on June 21, zero on September 21, and -23.5 deg on December 21; an annual cycle.
The moon's declination varies on approximately a monthly cycle, from around -26 deg to +26 deg, though the range does vary slightly.

It is useful to understand what the variation in lunar declination means in practice:

When the moon is at a declination of +26 deg, it is directly above a terrestrial latitude of +26 deg at its zenith (highest point). That puts it 60 degrees north of Sydney (latitude -34 deg), so its maximum elevation viewed from Sydney will be 90-60=30 degrees. At this declination the moon is above the Sydney horizon for about 9.5 hours.
When the moon is at a declination of 0 deg, it is directly above the equator at its zenith. That puts it 34 degrees north of Sydney (latitude -34 deg), so its maximum elevation viewed from Sydney will be 90-34=56 degrees. At this declination the moon is above the Sydney horizon for about 12 hours.
When the moon is at a declination of -26 deg, it is directly above a terrestrial latitude of -26 deg at its zenith. That puts it only 8 degrees north of Sydney (latitude -34 deg), so its maximum elevation viewed from Sydney will be 90-8=82 degrees. At this declination the moon is above the Sydney horizon for about 15 hours.

Two important things follow from these figures:

1. If you want to have an antenna in Sydney which can point directly at the moon at any time the moon is visible, then you need to have an elevation capability of up to 82 degrees - almost vertical.
    Of course, when the moon is at an elevation of 82 degrees in Sydney, it will not be visible at all in Europe or the USA, but it will still be "up" in many other countries.

2. When the moon is at its maximum southern declination, the amount of "moon time" is longest for us in Australia, but shortest for stations in the northern hemisphere.
    Conversely, when the moon is at its maximum northern declination, the amount of "moon time" is least for us in Australia, but longest for stations in the northern hemisphere.

Because the large majority of EME stations are located in the northern hemisphere, EME contests are always arranged when the moon is in northern declination!
However this does reduce the elevation requirements for VK stations during EME contests.

Where is the Moon?

It is possible to calculate for yourself where the moon will be at any time, but scarcely worth the effort!

There are many computer programs to do this for you. Some of these programs may give you the moon's position only at the current time, some at fixed time intervals, and some at any time of your choosing.
For actual operation using JT65B on 144MHz, look no further than K1JT's WSJT suite, but do open the Astronomical window in the View menu.
For advance planning I now use W5UN's Skymoon, with its nice map showing where the moon is visible all over the world. Other obvious contenders include GM4JJJ's MoonSked and VK3UM's EME Planner.
If you want to automate your antenna control (mine is still manual, which is fine on 144MHz), then you want a program with this facility.
See the EME Software page (not yet written!) for further details on programs. Meanwhile just Google them.

Calibrating Antenna Azimuth and Elevation

Knowing where the moon is located in the sky is only half the story. You also need to know where your antenna is actually pointing! Forget about using a compass or your GPS to find direction.

First find an accurate location for your antenna using a GPS - make sure the datum is set to GDA or WGS. A precision of 1 second of arc is good enough but you might as well use the full precision available (0.1 second).
Make sure that this position for your station is correctly entered in WSJT and/or Skymoon.
On a sunny day, use Skymoon to predict the exact time when the sun will be due north, and at that time mark a point on the ground high up on the shadow of your antenna mast, due south of your antenna. You now have an accurate reference point for south (and therefore north too).
If you don't have any software to predict in advance the exact moment when the sun is due north, enlist a helper to call out from the shack, or just run out to the antenna very fast!
Now all you need to do is to make sure the antenna points north when the rotator controller indicates this.

If you have a tilt-over tower, it is a good idea to use the above methodology to determine the exact direction in which your tower tilts over.
Then you can set the rotator controller accordingly (before lowering the tower), and adjust the antennas on the tilted tower so that they point exactly vertically.

For elevation readout there are many possibilities, such as a potentiometer on the antenna with a weight hanging from the potentiometer shaft, or a digital level.
I took a simpler option. I just use the indication on my elevation actuator controller with a manual calibration table.
To make the calibration table I set the antenna at various elevations (roughly 5 degree intervals), measured with a simple protractor and spirit level from a nearby fence post, and noted the controller reading.
Then I plotted this up and interpolated for the controller readings at 1 degree intervals. There is plenty of time to adjust manually both elevation and azimuth during the transmit period of JT65B.

Note that while it feels good to know that your antenna is pointing at the moon with 1-degree accuracy, it is simply not necessary on 144MHz.
With a single yagi, your 3dB points will be around +/- 16 degrees, and half this with a 2x2 array. Realistically 5 degrees of pointing accuracy is good enough.
I have had many successful EME QSOs with my antennas at their present maximum elevation of 52 degrees, and the moon 10 to 15 degrees higher, though I don't recommend this!