Hi Karen,
I am not a big expert on this topic, so maybe someone else would have something to say. My guess would be that the Chinese would have been documenting this sort of thing the longest. That is consistant with the information on this web page which discusses ancient solar eclipse observations:
http://eclipse99.nasa.gov...tions_Calendars.html
The Chinese were recording information about eclipses and other astronomical phenomena over four thousand years ago.
cheers,
Terry