classification: fire nation

Dear science side of Tumblr: 

Since total solar eclipses appear to be rare occurance in and round the Fire Nation capital, given this really old scroll:

And the ominous sounding “Day of Black Sun,” 

What can we assume about the nature of solar eclipses in the Avatar universe?

Would be safe to assume that because of this name given to it by the Fire Nation, that total solar eclipses usually occur either at sea, on the periphery of the Fire Nation, or in and around one of the other nations like the Earth Kingdom? 

Does moon/planet size have any effect on solar eclipses?