Measuring parallax angle, same local time or the same time I was thinking about measure the distance to the moon using parallax angle. But I have a confusion. I have read couple of articles about that, but one thing is unclear. Should we take pictures of moon at the same (literally the same, for example, taking both pictures at UTC 16) moment or should we take pictures the same local time (for example, if the timezone difference is 2h then the time difference between two taken pictures should be 2h).
So which one is the correct method for it? I think it is the former one, but I cannot tell why it is not the latter.
The simplest way: take pictures at the same (ie 16UTC). The position of the moon in the sky will be very different for different observers, due to the cuvature of the Earth.  But this is not what you are measuring. You need to see the difference in position relative to the stars.
For more accuracy, instead of measuring the difference is position directly, you can time when the moon occludes a star. The absolute time when the moon will occlude a star will differ for different observers, and this can be converted into a difference of position of the moon, and parallax can be calculated from that.  It is easier to be accurate in timing than it is to measure position directly. With some clever maths you can just measure the length of the occulution rather than the absolute time, and this means you don't even need a accurate clock, you only need an accurate stopwatch (not so much of an issue now, but significant when these measurements were first being done)