The Moon's rotational speed

[ReloadPsi]

How is that relevant to the purpose of this thread?

In other words,

From the Dollet scene (the Moon on the water) -> The Timber Train scene (the Moon in the background). Now, do they look exactly the same?

That whole timetline sounds like a lot less than 28 days to me - a few days at most.

Yup.

Disc 1 takes place over the course of two days.

Day 1: Go to Fire Cavern, head back, go to Dollet, go to party, go to training centre, go to new dorm, sleep.

Day 2: Go to Timber (take a short nap along the way), do the train thing, head to the TV station, head to Galbadia Garden by train (again with a short nap along the way), get your assassination orders, attempt to kill the sorceress. Black out.

At no point does it indicate that more than a single day passes during "day 2" and staying at an inn doesn't actually pass time in RPGs.

Disc 2

Day 3: After a Laguna dream, which could well happen overnight, escape from prison, missile base, make the Garden levitate.

Day 4? Rinoa comes in and asks for a tour.

Day 5? Rinoa asks for a walk. If you didn't bring Rinoa, Quistis asks if you want to go and get a cup of tea and have a talk.

After this it gets a bit ambiguous, but given that Mayor Dobe doesn't yet know of Deling's death, it could very easily be a very short time after day 2 that you arrive at Horizon. From here on, due to the fact that Garden is mobile and travel by sea would take days, there's no way of knowing how many days pass, but it could very easily be less than 28 given how much these guys can do in a single day!