Hubble Space Telescope Homepage – Learn about one of NASA’s workhorse observatories as well as the most recent press release image from the telescope, which as been in observing the universe for over 20 years.
Mars Exploration Homepage – Information and news about any of the past and current missions in orbit around or on the surface of the red planet.
Cassini Mission @ Saturn Homepage – Breath-taking images from the Cassini mission currently, which ended in 2017. Also includes highlights of the mission that has been at Saturn since 2004.
Messenger @ Mercury Homepage – Learn about the closest planet to our Sun as well as new discoveries that were made with data from the Messenger mission.
New Horizons Mission – Homepage of the New Horizons mission, which performed a fly-by of the Pluto system in 2015 and is currently on its way to other Kuiper Belt objects.
Vanderbilt University Homepage – Homepage of Vanderbilt University in Nashville, TN.
http://www.dicts.info/terminology/glossary.php?field=astronomy – Online astronomy encyclopedia, dictionaries, and translations of astronomy terms between multiple languages including English, French, Chinese, and German.