Final answer:
Jeremiah Dixon and Charles Mason were astronomers, recognized for their astronomical work and contributions to surveying, such as their work on the Mason-Dixon line.
Step-by-step explanation:
Jeremiah Dixon and Charles Mason were both astronomers. They are historically recognized for their work in the field of astronomy, not only for observing celestial bodies but also for their contribution in surveying the Mason-Dixon line, which is often mistakenly thought to relate to the practice of cartography. However, their primary profession, in line with their notable achievements and as referenced in the context of their work, was indeed astronomy. When considering their profession alongside historical figures like Henry Draper, James Lick, Tycho Brahe, and Johannes Kepler, all of whom made significant contributions to astronomy, it's clear that Mason and Dixon's surveying work was informed by their astronomical expertise.