According to the extreme perspective changes, there is a different view of the Moon when it is overhead, versus at a 45 degree angle.
No, this is simply according to the textbook definition of how the Moon orbits the Earth. It shows a different phase when at 90 degrees to the Earth-Sun axis than when it is at 45. But there's approx 3.5 days between each.
For the Full Moon:
IMG
The view at 45 degrees shows a Moon which is shifted in orientation, and tilted upwards or downwards from the overhead view, as the perspective changes demand.
That's NOT a "full Moon". There's also approximately 3.5 days between any single observer seeing the first phase, and then the other. The Moon cannot be in two places at once.
Here is a to-scale diagram of the Earth-Moon system. There are two observers, Red and Blue. When one viewer views the Moon overhead, the other is viewing it at 45 degrees:
IMG
NO. Each observer will see the first phase of the Moon at one time, THEN, 3.5 days or so later, they will see it in its second phase
Q1. If there is a difference in Moon phase when viewed at 90 degrees and 45 degrees for each observer due perspective changes, how can both observers, each with their own personal perspective, view the same Moon with the same phase at the same time?
There is no significant difference in the Moon phase as it moves across an observer's sky on any given day or night.
Q2. Further, if the observer moves from one position to the next, it would suggest that the phase would change, as the observer is observing the Moon at 90 or 45 degrees. A rotating earth would have observers moving from one position to the next.
NO. The phase changes only to the extent of the few degrees I showed above, which for the observer moving on the face of the Earth, viewing with the naked eye, on any one day or night, will be no visible change at all. Please refer to my earlier post
Even if we abandon the idea that there are two observers with their own personal perspective and say that the Earth as a whole is One Observer, and the Moon is shifting in perspective at it moves around the Earth, the Earth is still rotating faster than the Moon is moving, causing the Moon to be 90 degrees overhead or 45 degrees overhead over a span of hours.
If the Earth as a whole is "one observer", then it's rotational rate does not matter.
However, in actuality, the Moon has not moved to any significant extent in that time, so it still has essentially the same face illuminated by the sun. The same phase.
Once again, please show us a working system which can get these extreme perspective effects working in a coherent system.
Shown you that already. You were shown it in the previous thread wherein you raised the "moon tilt illusion". This isn't our first rodeo on this topic.
Once again - in the time that a single observer takes to move from E1 to E2, the Moon moves from the right-hand dotted line of sight to the left-hand one.
No significant change in phase. No 45 degree movement of the Moon. Just a few degrees in its orbit. Meanwhile, the observer on Earth has seen the Moon go from directly overhead to being on their horizon.