网站简介：timeanddate.com注册于1997年，于1998年5月24日正式上线。在上线的第一天，网站吸引了24位用户。timeanddate.com最初的服务项目包括日历，世界时钟等，这些都是在1995年10月正式启动的。timeanddate.com自从创业开始就取得了稳定的发展，现在已经成为了世界上时间和日期服务网站中最为流行的一个。
网站简介：Fully automated electronic archive and distribution server for research papers, hosted at the Los Alamos National Laboratory.
网站简介：Offers space, astronomy and technology content, including information, education, entertainment and business news.
网站简介：On-line Store with wide selection of brand name binoculars, monoculars, telescopes, spotting scopes, rifle scopes, opera glasses, laser sights, range finders, and night vision equipment. Located in Illinois.
网站简介：Complete guide to times in every time zone in the world.
网站简介：Features a different image or photograph of our universe each day, along with a brief explanation written by a professional astronomer.
网站简介：Intergovernmental, European organisation for astronomical research, operates many observatories in Chile. Here you will find full scope information about every project, news, technologies and observations.
网站简介：New and reconditioned surgical microscopes for various applications including colposcope systems, and disposables.
网站简介：Objective reviews for astronomy equipment and accessories submitted by expert and amateur astronomers. Articles, classifieds, and forums.
网站简介：News center, gallery, discoveries, sci-tech, fun and games, and reference desk.
网站简介：Science news and information about the Sun-Earth environment.
网站简介：General interest astronomy magazine published in Cambridge. News, tips, sights, and resources.
网站简介：An extensive astronomical learning system. Articles available at three levels: beginner, intermediate, advanced.
网站简介：The USNO mission is to determine the positions and motions of celestial objects, to provide astronomical data, to measure the Earth's rotation and to maintain the Master Clock for the United States.
网站简介：A sport optics company which manufactures a complete product line of binoculars, spotting scopes, riflescopes, monoculars, tripods and accessories.
网站简介：Part of NASA's Office of Space Science that describes NASA's program to explore the solar system.m.
网站简介：Online program that include graphics generated in real-time and customized for a location and time zone to observe satellites such as ISS, space shuttle, and iridium flares.
网站简介：The program downloads and analyzes radio telescope data from the Berkeley Search for Extraterrestrial Intelligence.
网站简介：Provides latest news on astronomy and guides on the buying of astronomical products.
网站简介：Several product lines of telescopes, binoculars, spotting scopes, microscopes and eyepieces, plus a large variety of accessories.
网站简介：Provides information about new discoveries made by the space telescope. Includes technical data, astronomical photos and news releases.
网站简介：A nonprofit organization devoted to the exploration of the solar system and the search for extraterrestrial life.
网站简介：Astronomical research center responsible for operating the Hubble Space Telescope as an international observatory.
网站简介：Sells telescopes, binoculars, and accessories for amateur astronomers and nature enthusiasts through an on-line shopping cart and printed catalog. Large selection, same-day shipping, and a 100% satisfaction guarantee. Offices located in California.
网站简介：Auroral forecasts, educational material on aurora and related science, plus areas for other geophysics disciplines (earthquakes, volcanoes, climate, weather, glaciers, and tectonics).
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