I know you would use but to combine two opposite ideas, and use and to combine two similar ideas. And I understand that similar would imply that the relationship between the two should not be cause and effect or one that explains the other, so they are two separate thoughts.
The two sentences below are similar, but the second one explains or details the first, and so, I think, it does not lend itself to coordination using and.
Saturn has about twenty moons. Titan is the largest.
In other words, what do you think of combining the previous sentences with and?
Saturn has about twenty moons, and Titan is the largest.
The example was a run-on sentence from the book Elements of Language, and was fixed by splitting the two ideas. However, I would like to find out whether the approach was the only way or just a matter of preference.