| Name | Website | Introduction |
| timeanddate.com | timeanddate.com | timeanddate.com was registered in 1997 and officially launched on May 24, 1998. On the first day of its launch, the site attracted 24 users. timeanddate.com’s initial services included calendars, world clocks, etc., which were officially launched in October 1995. timeanddate.com has achieved steady growth since its inception and is now one of the most popular time and date service sites in the world. |
| arxiv.org | arxiv.org | Fully automated electronic archive and distribution server for research papers, hosted at the Los Alamos National Laboratory. |
| space.com | space.com | Offers space, astronomy and technology content, including information, education, entertainment and business news. |
| opticsplanet.com | opticsplanet.com | 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. |
| wwp.greenwichmeantime.com | wwp.greenwichmeantime.com | Complete guide to times in every time zone in the world. |
| Apod.nasa.gov/apod/astropix.html | Apod.nasa.gov/apod/astropix.html | Features a different image or photograph of our universe each day, along with a brief explanation written by a professional astronomer. |
| eso.org | eso.org | 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. |
| zeiss.com | zeiss.com | New and reconditioned surgical microscopes for various applications including colposcope systems, and disposables. |
| cloudynights.com | cloudynights.com | Objective reviews for astronomy equipment and accessories submitted by expert and amateur astronomers. Articles, classifieds, and forums. |
| hubblesite.org | hubblesite.org | News center, gallery, discoveries, sci-tech, fun and games, and reference desk. |
| spaceweather.com | spaceweather.com | Science news and information about the Sun-Earth environment. |
| skyandtelescope.com | skyandtelescope.com | General interest astronomy magazine published in Cambridge. News, tips, sights, and resources. |
| windows2universe.org | windows2universe.org | An extensive astronomical learning system. Articles available at three levels: beginner, intermediate, advanced. |
| usno.navy.mil | usno.navy.mil | 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. |
| vortexoptics.com | vortexoptics.com | A sport optics company which manufactures a complete product line of binoculars, spotting scopes, riflescopes, monoculars, tripods and accessories. |
