Photographic investigations of faint nebulae

"Photographic Investigations of Faint Nebulae" by Edwin Hubble is a scientific work from the early 1900s that digs into the study of nebulae using photography. The story carefully looks at and catalogs dim nebulae located far past our solar system. Hubble dives into 512 nebulous objects not previously on record ordered into clusters. He makes clear how impactful photographic plates have been to astronomy. The story starts with an overview of nebulae and the shift from visual to photographic ways of seeing them, showing all the benefits of the newer form. Hubble goes over existing knowledge about the characteristic and classification of new nebulae, pointing out that around 17,000 are known, with possibly many more still undiscovered. He lays out his organized method of observing at Yerkes Observatory along with the system used to classify these cosmic wonders, while also showing the problems with measuring dim objects in the night sky. This sets up a more detailed journey of the discoveries that are talked about later in the story.