Complex sentence: She studies the movements of planets in the heavens and lost an eye one thousand years earlier observing the last Great Conjunction of the Three Suns, which not only burned out her eye, but also burned her body.
Split into simpler sentences: She studies the movements of planets in the heavens and lost an eye one thousand years earlier observing the last Great Conjunction of the Three Suns. This not only burned out her eye, but also burned her body.