Passage: Astronomers such as David Morrison argue that the galactic equator is an entirely arbitrary line and can never be precisely drawn, because it is impossible to determine the Milky Way's exact boundaries, which vary depending on clarity of view. Jenkins claimed he drew his conclusions about the location of the galactic equator from observations taken at above 11,000 feet (3,400 m), an altitude that gives a clearer image of the Milky Way than the Maya had access to. Furthermore, since the Sun is half a degree wide, its solstice position takes 36 years to precess its full width. Jenkins himself noted that even given his determined location for the line of the galactic equator, its most precise convergence with the center of the Sun already occurred in 1998, and so asserts that, rather than 2012, the galactic alignment instead focuses on a multi-year period centered in 1998.There is no clear evidence that the classic Maya were aware of precession. Some Maya scholars, such as Barbara MacLeod, Michael Grofe, Eva Hunt, Gordon Brotherston, and Anthony Aveni, have suggested that some Mayan holy dates were timed to precessional cycles, but scholarly opinion on the subject remains divided. There is also little evidence, archaeological or historical, that the Maya placed any importance on solstices or equinoxes. It is possible that only the earliest among Mesoamericans observed solstices, but this is also a disputed issue among Mayanists. There is also no evidence that the classic Maya attached any importance to the Milky Way; there is no glyph in their writing system to represent it, and no astronomical or chronological table tied to it.

Question: What profession is David Morrison?
Astronomers