Maybe the author had forgotten about them?

There’s a sentence about halfway through the article that specifies what they mean by “half-forgotten”:

He added the significance of Kepler’s solar drawings was overlooked, over the eras: “It has only been discussed in the context of the history of science and had not been used for quantitative analyses for the solar cycles.”

Imo it’s not-so-crappy journalist speak (for once).

Not forgotten at all but not talked about for a whole year.