Version of 2011-09-09, Martin Elsaesser
There is one reliable fact regarding crescent orientation: the crescent is ALWAYS located on the side of the lunar disk that is nearest to the sun (as the crescent is the very edge of the illuminated part of the lunar sphere visible). I call this "the crescent points toward the sun". The horns of the crescent arc point somewhere else of course, almost in the opposite direction for a wide crescent.
If you always turn your head or a captured image in such a way, that the north-pole of the lunar disk points up and the south-pole points down, then some more can be said:
A waxing crescent will always appear on the western=right side of the lunar disk, while a waning crescent will appear on the eastern=left side.
Be aware that this standard-orientation can be very different from the usual horizontal view of a human observer. For example, from high southern latitudes on earth, the north-pole of the moon always points down.
So the crescent always points towards the sun. How this appears to an observer (right, left, up, down from the sun) depends on the orientation of the observer. As the observers are located somewhere on earth (which is a sphere), they can have ANY orientation (as their head will always point away from the center of the earth, assuming they stand upright), so the lunar disk can appear in any direction from the sun (the disk itself can thus be oriented in any way) and so the crescent can point in ANY direction in the sky. But this direction will ALWAYS point towards the sun, and a waxing crescent will always appear on the western part of the lunar disk.
The following images show a comparison of the situation on 29. August, as seen from Munich, Germany and Johannesburg, South Africa.
Situation on 29. August: orientation of sun and moon as seen from Munich, Germany, looking south-east.
Be aware that the lunar disk itself appears somewhat rotated, with the north-pole on the upper left side.
Situation on 29. August: orientation of sun and moon as seen from Johannesburg, South Africa.
The orientation is very different now, as we have moved 75° south on the earth and are looking in a different direction in the sky, towards the north-east.
The north-pole of the moon is pointing DOWN and to the LEFT.
An additional issue is camera orientation. You can attach the camera to your optics in all possible rotations, which would result in all possible orientations of the image of the lunar disk. (You can easily make an image with clouds on the bottom and the houses on the upper edge, by turning your camera upside-down.)
So it makes good sense, to use a well known orientation of the camera, usually parallel to the horizon or in line with the celestial coordinate system.
With my images from 29. August 2011 the camera was aligned with the horizon, just as a visual observer would look at the sky: the upper-edge of the image is up in the sky, the right-edge of the image is right in the sky. The view in the sky is demonstrated by the first image on the page: it shows that from Munich, at that time of the day, the lunar disk was below and slightly to the right of the sun. So, at that time of day in Munich, the crescent pointed up and slightly to the left and that is what the image shows.
The north-pole of the lunar-disk is on the upper left of the invisible lunar disk.
The moon had clearly moved past the sun along the ecliptic and with the distance widening again this was clearly a waxing crescent.
So, in order to determine if an image of the crescent was taken before or after conjunction, you would need to look very closely at the image, trying to identify lunar structures such as craters or mountains. This is very difficult with very thin crescents, which hardly show any lunar details, so you usually have to go from the time and date.
If that time/date is after conjunction, then it would be regarded as a waxing crescent of the new lunar cycle, which i assume to start at conjunction.
Whether such an early observation is used for religious calendars is a different issue. Calendar use should not affect the use of the well established terms "waning" or "waxing".
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