- General, supernova remnants, planetary nebulae, diffuse nebulae, dark nebulae, open clusters, globular clusters, galaxies, clusters of galaxies, double stars, and references.
- Observing guide, articles, Messier Gallery, Herschel 400 and Deep Sky Browser which allows the ability to search deep sky objects and view maps and images of over 600,000 objects.
- Contains information, challenges, galaxy clusters, globular clusters, open star clusters, naked eye observations, observing planetary nebulae, the Milky Way, and star hopping.
- An attempt to correctly identify all the original objects, starting with the original discoverer's notes and working forward in time to encompass the work of contemporary astronomers, both professional and amateur.