An explanation is included. An amateur astronomer put together this website to assist other observers by providing accurate positions and information on various comets and meteor showers, along with photographs. Also included are a glossary and links to other sites. The IOP is a professional body for physicists. Its website has the Institute's activities, membership, and free online services, such as job openings.
Registration is necessary to access online articles.
The NASA website is a gateway to a vast amount of information about America's space program. Here you will find a webpage for each current NASA mission, manned or unmanned. Each mission page includes links to images, news, spacecraft info, and mission profile. About NASA itself, there is information about the agency's organization, administration, and facilities. Also included is an article service, a digital library, astronomical data catalogs, and archives.