@Background Pony #D07A 
Yeah, I was thinking of that when I wrote that last paragraph.
 
Zenith, Right Ascension and Declination, the Meridian, all that stuff. It’s been awhile since I’ve taken the introductory astronomy course, and I don’t really use astronomical tools much where I’m going as a theorist.

@Cirrus Light 
Er, are you not familiar with celestial coordinate system (horizontal)?.. Because that’s what she’s depicting, not “flat world”.

When I first saw that, I saw the equation with the reduced Planck’s constant and I got mad at her for using that and dividing it by 2 pi, when I suddenly realized that it’s 2M, not 2pi.
 
…And I think I’ve got the relationship in-between the Planck constant and reduced Planck’s constant backwards :p
 
@IceKitsune  
I hope not - it looks like a flat world model, but we clearly see murals depicting a regular solar system in Celestia’s throne room:
 

 
Or from Celestial Advice:
 

 
The proof that Equestria is heliocentric is literally in the intro to every single episode.
 
I definitely prefer that headcanon. The thought that their universe is smaller than that or otherwise weird is just… it freaks me out. It’s clausterphobic to imagine a world like that. Though I guess that depends on a lot of things.
 
But then again, the illustration she has works pretty well even on a round world, if you’re just looking at one patch of ground that’s approximately flat. Just as long as she’s not talking about their entire world…

Interesting, I wonder who she is explaining how the Sun and Moon work too? That looks like what she is doing anyway. Logically it would have to be either someone who is not from their world or a young child.

stop doing a rain dance spike