What is the fine-grained topic of the following text: The map, by the well-known celestial cartographer Wil Tirion, shows stars down to magnitude 4, plus several deep-sky objects, such as the Pleiades, the Large and Small Magellanic Clouds (LMC and SMC), and the Orion Nebula (M42). Only return the topic.
Celestial Map by Wil Tirion