Astronomy has great potential to attract children toward science and improve their scientific literacy. However, it has a relatively small presence within the school curricula worldwide. In Chile, home of the world's largest telescopes, astronomy is even more relevant in science education, but the presence of astronomical content within the national curriculum was not studied yet. In this context, this article characterizes the opportunities to learn astronomy within the Chilean science curriculum from grades 1 to 12. A mixed descriptive design with documental analysis is conducted to determine which science learning objectives (LOs) are directly or indirectly related to astronomy and classify them according to astronomical topics, cognitive processes, and Big Ideas in Astronomy. The proportion of LOs related to astronomy within the whole science curriculum and the categories of interest are calculated and compared over the school grades. The results show that the LOs directly related to astronomy are present only in a third of the grades and include a small variety of astronomical topics. Meanwhile, LOs indirectly related to astronomy appear in all grades and include more topics and higher cognitive processes. We discuss the implications of the outcomes and raise some possibilities to promote astronomy literacy through interdisciplinary work.