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://astrosurf.com/cidadao
António Cidadão's dedicated astronomy site showcases years of lunar and planetary observation from Carcavelos, Portugal, featuring CCD imaging of the Moon, Mars, Jupiter, and Saturn captured with a 14-inch SCT telescope. The site includes detailed imaging guides covering super-resolution techniques, tri-colour imaging, limb darkening correction, time-lapse animations, and a Moon-Light Atlas reference, making it a rich resource for amateur planetary imagers.
http://wd0hwt.net/
The Metro Area Repeater Association (MARA) operates the WD0HWT repeater system serving the Minneapolis/St. Paul, MN region on 146.25/.85 and 449.800/444.800 MHz. The site covers repeater rules of conduct, system description, history, emergency communications support, and membership contribution details for Twin Cities area amateur radio operators.
http://bozonets.com/
Bozo Net is a VHF/UHF amateur radio community site centered around the Los Angeles and Central California ham radio scene, with a charming origin story about the 144.200 MHz national calling frequency and how the nickname 'Bozo' was born. The site covers topics like beacon info, HOA antenna restrictions, tower raising, and links to ARRL legislative efforts affecting amateur radio operators.
https://planetmath.org/
PlanetMath.org is a collaboratively built mathematics encyclopedia where community members write and review entries covering a vast range of mathematical topics, all rendered in LaTeX. Hosted by the University of Waterloo and operated as a nonprofit, it offers both a subject index and alphabetical index, making it a serious reference hub for students, educators, and math enthusiasts.
https://complex-analysis.com/
Created by Juan Carlos Ponce Campuzano, this interactive online textbook introduces complex analysis through visual applets built with GeoGebra, p5.js, and other JavaScript tools, making abstract mathematical concepts tangible and explorable. Covering topics from the Cauchy-Goursat Theorem to conformal mappings, it serves engineering and mathematics students with a beautifully designed, continually updated resource that includes Spanish and Italian translations.
https://www.qsl.net/sparc
The Hamilton County Amateur Radio Club serves the Adirondack Mountains region of New York, coordinating repeaters, emergency communications nets, and ARES/RACES operations across Hamilton and neighboring counties. Visitors will find meeting schedules, repeater frequencies, event listings like Field Day and the Southern Adirondack Hamfest, and resources for anyone interested in getting a ham radio license.
http://cbat.eps.harvard.edu/index.html
The Central Bureau for Astronomical Telegrams (CBAT), hosted at Harvard University since 1966, is the official IAU clearinghouse for announcing new astronomical discoveries including comets, novae, supernovae, and other transient celestial events. Visitors can browse online IAU Circulars, subscribe to discovery feeds, explore lists of supernovae and comets, and learn how to submit their own astronomical observations.
https://go-astronomy.com/astro-club-search.htm
GO ASTRONOMY hosts a comprehensive directory of over 600 amateur astronomy clubs across all 50 U.S. states, plus international listings spanning countries from Japan to Germany. Visitors can search by state to find local clubs offering meetings, star parties, viewing nights, and stargazing programs, making it an essential starting point for anyone wanting to connect with fellow astronomers.
https://irts.ie/cgi/index.cgi
The Irish Radio Transmitters Society (IRTS) is Ireland's national amateur radio organization, offering licensing guidance, club directories, contest calendars, and membership services for ham radio enthusiasts across the country. Affiliated with the International Amateur Radio Union, the site serves as a central hub for Irish operators with resources covering repeaters, beacons, DXCC standings, awards, and emergency communications.
http://kf6c.com/
KF6C is an amateur radio operator's site featuring information on remote radio operation, custom transceiver designs like the SL600 and G3ZVCmkII, and vintage radios including Eddystone and Collins equipment. Visitors can also browse hard-to-find parts and accessories for sale, making it a useful stop for both radio hobbyists and collectors.