Historians establish the facts of history, of what happened in the past. They do this with a variety of sources, some documentary, some physical, and whatever else they find is relevant. Key particulars are more significant than universals in establishing the facts of history. Historians may consider scientific theory in doing this, but they may also conclude that some things happened that don’t fit well with current scientific theory. Whether or not there was an earthquake in 1755 that destroyed Lisbon is a matter of history, not science.
Scientists are dependent on historians for the facts of history. Scientists do not get to establish the facts of history, nor the limits of what could have happened in the past. The latter restriction is difficult for scientists to observe. If historians establish facts that don’t fit well with current scientific theory, then scientists are likely to react defensively rather than revise their theories.
Biblical (or creation) scientists consider the Bible as the key to history, and limit science to that which is consistent with biblical chronicles. As with all scientists, they depend on historians for facts about the past but not all historians have a high view of the biblical record. Disagreements among historians lead to variations in science, since they are working with different facts about the past.
The different rôles of historians and scientists are often confused. Astronomy is a case in point. Astronomical historians may work with documents produced by those who could be considered scientists from the distant past. But the interpretation of ancient or medieval scientific documents is not part of science. Astronomical historians deal with the particulars of history, in which universals play only an indirect rôle.
Astronomical scientists deal with universals, as all scientists do, and make use of the facts of history along with recent observations. Scientists may advise historians but science is dependent on history for facts about the past, not the other way around.