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WikiPedia: Đài quan sát http://cleardarksky.com/cgi-bin/find_clock.py?keys... http://robslink.com/SAS/democd32/observatories.htm http://files.library.northwestern.edu/findingaids/... http://physics.usc.edu/solar/ http://www.whoi.edu/institutes/coi/viewTopic.do?o=... http://www.whoi.edu/institutes/occi/viewTopic.do?o... http://www.whoi.edu/sbl/liteSite.do?litesiteid=773... http://solarsystem.nasa.gov http://solarsystem.nasa.gov/missions/profile.cfm?M... http://www.wvuo.info