Question

Ancient physicists tried to determine the orbits of the planets. Every night they carefully tracked the location of the planets and stars they observed. What kind of investigation were these physicists conducting?

Answer 1

My guess would be descriptive . It would not be experimental, because these astronomers can not in any way manipulate the stars . They are merely observing. 

Answer 2

observational investigation/study

Step-by-step explanation:

Observational investigation is the kind/type of investigation whereby the person carrying out the investigation will draw conclusion/results about their investigation based on the facts they observed without having a direct influence on the facts.

Ancient physicists in the bid of trying to determine the orbits of the planets they had to observe the location of the planets and stars every night in order to draw a conclusion on how the Orbits of the planets is. this is strictly observatory because the location of the planets and stars every night cannot be changed by the physicists.