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)
http://jgiesen.de/welcomeEnglish.htm
A rich hobbyist resource by J. Giesen featuring an extensive collection of Java and JavaScript applets covering astronomy topics like sun and moon phases, planet positions, sundials, Venus transits, and satellite observation. Visitors will also find physics quizzes, chaos and fractal simulations, color theory tools, and links to books and software, making it a deep interactive playground for science enthusiasts.
https://astroring.auroradynia.com/
The Astronomy Webring, hosted by auroradynia, connects enthusiasts of astronomy, astrophotography, and astrophysics across the old web. Visitors can join the ring, browse the member list, or simply hop between sites dedicated to all things space.
http://kellysky.net/
Al Kelly's dedicated astrophotography site showcases stunning CCD images of galaxies, nebulae, star clusters, and solar system objects captured with equipment including a Celestron CGE 1400 telescope and Orion Parsec 8300C camera. Beyond the image galleries, the site offers a CCD instruction manual, a G2V color calibration article, and links to fellow astrophotographers, making it a valuable resource for amateur astronomers interested in CCD imaging.
https://www.qsl.net/barc
The Bristol Amateur Radio Club (BARC) serves ham radio enthusiasts in the Bristol, TN/VA area, with information about their local FM and C4FM repeaters, monthly meetings, newsletters, and contesting activities. A long-running club site hosted on QSL.NET, it connects members and visitors to resources for advancing amateur radio knowledge and community involvement.
http://mathpuzzle.com/loyd
Ed Pegg Jr's digitized archive of Sam Loyd's 1914 'Cyclopedia of 5000 Puzzles, Tricks, and Conundrums' presents the classic puzzle book as a complete set of scanned page images freely available for download. This rare public-domain release preserves one of the most celebrated puzzle collections in mathematical history, making it an invaluable resource for recreational mathematics enthusiasts.
https://hypertextbook.com/chaos
The Chaos Hypertextbook is a deep educational resource covering chaos theory, fractals, strange attractors, and fractal dimension with clear explanations aimed at making complex mathematics accessible to a broad audience. Organized into chapters covering iteration, bifurcation, Julia sets, Mandelbrot sets, and nonlinear dynamics, it reads like a beautifully structured online textbook that would captivate anyone curious about the mathematics underlying unpredictable systems.
https://cpcug.org/user/wfeidt/Arldx/index.html
A personal DX travel resource by W. Feidt, hosted on the Capital PC User Group server, focused on amateur radio DX expeditions and rare entity activations around the world. Visitors will find logs, country information, and expedition details useful for ham radio operators interested in chasing rare DXCC entities.
http://currentsky.com/
Bob Riddle's 'Qué tal in the Current Skies' is a long-running amateur astronomy site that began in the late 1980s as posts to the Big Sky Telegraph BBS and evolved over 30+ years into a web resource covering Earth and Space topics. The site now serves as a transitional landing page pointing visitors to his continuing work on Substack, with archived daytime and nighttime sky photos, calendar data, and astronomical observations.
https://www.qsl.net/evarc
The Elkhorn Valley Amateur Radio Club (EVARC) serves ham radio enthusiasts in Norfolk, Nebraska, with meeting schedules, repeater frequencies, club nets, and licensing test sessions. Maintained by Monty Wilson NR0A, the site also links to propagation tools, ARES registration, local hamfest info, and nearby radio clubs across Nebraska.
![en:start [Skychart]](/screenshots/15841.webp)
https://ap-i.net/skychart//en/start
Skychart, also known as Cartes du Ciel, is a free open-source planetarium program that lets users draw detailed sky charts using star and nebula catalogs while also displaying the positions of planets, asteroids, and comets. This multilingual wiki serves as the official documentation and download hub for the software, supporting Linux, Windows, and macOS with both stable and beta releases.