The archives also contain several illustrations created by astronomers at the Lick Observatory, namely James Keeler, James Schaeberle, and Holden himself. Astronomers particularly used illustration to observe and record the visible features of the planetary surfaces as they rotate.
This collection of documents leads us to wonder what impact artists like Trouvelot had on the way astronomers at the Lick perceived the cosmos, and how artistic representations might have ultimately shaped the photographic images they produced. Although Holden himself found photographic imaging to be superior to illustration in their capacity to record detail, his scrapbook contains several of his own drawings of astronomical objects, and he collected illustrations in his personal files. He notes that his illustrations have "little artistic merit," but as demonstrated on the next path, it seems that Holden may have perceived the cosmos through the eyes of an artist after all.