Answer:
2. Combining old and new observations.
Explanation:
Through the passage, Nicholas Copernicus is introducing to the reader a new worlds, based on observations from the pass, and recent observations made by scientists. Basically, he's talking about a work where the reader is going to able to learn and be aware about the stars and planets movements in a way that no one could imagine before.
Copernicus specifically states that those observations are based on ancient and new data.
Therefore, the right answer is 2, because it's a combination of old and new observations.