Science & Nature
1439 sites
Subcategories:
- Astronomy & Space (396)
- Chemistry (8)
- Earth Sciences (26)
- Biology (79)
- Physics (30)
- Mathematics (59)
- Weather & Climate (104)
- Amateur Radio (682)
- Electronics (47)
https://ng3k.com/
Bill Feidt (NG3K) has built a comprehensive amateur radio resource focused on DX operations and contesting, featuring the Announced DX Operations (ADXO) database, DXCC entity tables, packet cluster resources, and propagation forecasts. With archives stretching back to the mid-1990s and regularly updated links to DX tools, contest calendars, and reverse beacon networks, this site is a go-to reference for serious DX and contest operators.
http://deepskystacker.free.fr/english/index.html
DeepSkyStacker is a free software tool designed for astrophotographers who want to stack and process deep-sky images to reveal faint celestial objects. The site offers downloads, screenshots, a user manual, FAQ, technical details, and tutorials for getting the most out of the application.
https://www.qsl.net/pkrs
The President Karami Radio Society (PKRS) is an internationally recognized amateur radio club based in Tripoli, Lebanon, operating under the callsign OD5RAK. The site covers club history, members, awards, technical resources, and eQSL information, offering a window into ham radio culture in northern Lebanon.
https://dx4win.com/
DX4WIN is a logging and DX management software site for amateur radio operators, focused on tools to track contacts and DX entities. The site uses a frames-based layout typical of early web design, suggesting it has been around since the early days of the internet.
http://sss-mag.com/smith01.html
SSS Online is a long-running RF and spread spectrum engineering magazine offering deep technical resources on Smith charts, S-parameters, impedance matching, Eb/N0, and link budgets. Managed by Pegasus and active since 1995, it serves RF engineers and ham radio enthusiasts with articles, software downloads, tutorials, and reference material on microwave and wireless design topics.
http://cvafresno.org/
The Central Valley Astronomers is an amateur astronomy club based in Fresno, California, welcoming everyone from beginners to seasoned professionals with star parties, astrophotography, and educational meetings. The site includes a club calendar, membership info, a Young Astronomer Program, star party etiquette guides, light pollution resources, and tips on purchasing equipment.
http://backbayastro.org/
The Back Bay Amateur Astronomers (BBAA) is a non-profit astronomy club serving the Hampton Roads, Virginia area, dedicated to public outreach and bringing stargazing to the community since 1978. The site offers event calendars, observing programs, a photo gallery, telescope donation info, scholarships, and archives of newsletters and eclipse coverage.
https://cobaltpet.blogspot.com/
Run by a Northern California hobbyist known as 'weatherall', this blog chronicles shortwave and mediumwave radio listening with detailed reception reports, SIO signal quality codes, station identifications, and portable receiver reviews. Covering international broadcasters, number stations, utility signals, NDB logs, and DXing tips, it's a thorough record of the hobby for fellow shortwave enthusiasts.
https://umbra.nascom.nasa.gov/eclipse/980226/text/filter-sources.html
Part of NASA Reference Publication 1383, this page provides a curated list of U.S. vendors selling mylar and glass solar filters safe for eclipse and solar viewing with or without a telescope. It includes contact details for well-known optics companies like Celestron, Meade, and Orion, making it a practical companion resource for amateur astronomers preparing for solar observation.
https://vvara.org/
The Verde Valley Amateur Radio Association (VVARA) serves ham radio enthusiasts in North-Central Arizona, hosting regular club meetings, training presentations, and multiple weekly nets including trivia and rag chew sessions. The site also features a live weather station and camera feed from Mingus Mountain, making it a useful local hub for both radio operators and weather watchers.