| 5. | NGC/IC Project | | | Objective is to correctly identify all of the original NGC and IC objects. Starts with the original discoverer's notes and moves forward to encompass the work of contemporary astronomers, both professional and amateur. www.ngcic.org |
| 6. | The Messier Catalog | | | Images and information for all Messier objects from Students for the Exploration and Development of Space (SEDS). www.seds.org |
| 9. | Messier45.com | | | Online tools for deep-sky observers, including maps and lists of objects with pictures and data. Messier45.com |
| 12. | Deep Sky Observer | | | Information, images, charts for the Messier, Caldwell, NGC, and Hubble with search tool. www.utahskies.org |
| 13. | The Caldwell Objects | | | Information, images, charts for the Caldwell Objects as taken from the weekly Utah Skies Report www.utahskies.org |
| 14. | Messier Marathon | | | Includes instructions, complete biography, annotated catalogue and search tool. www.messiermarathon.com |
| 15. | A CCD Tour of the Universe | | | Includes deep sky objects search, images of all Messier and many NGC and IC objects, mosaics of large nebulae and galaxy clusters. astrosurf.com |
| 16. | Deep-Sky.Org | | | Features a reference of Messier objects, telescope information, and deep-sky links. deepskyorg.tripod.com |
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