- USNO: Rise, set and twilight definitions by U.S. Naval Observations.
- International Comet Quarterly: Definitions and explanations of comet and astronomical terms.
- NOVAC: Glossary of terms used by the Northern Virginia Astronomy Club.
- Chinese Astronomy: Solar Terms and the Chinese Calendar
- Sea and Sky’s Astronomy Resources: Non-technical explanations of astronomical terms.
- SkyEye Online Glossary: Definitions of the most common words used in astronomy, astrophysics, cosmology, and space exploration.
- Science U: Terms used in the S.U. observatory.
- Astronomy Links: A general index with search databases, calendars, history and other interesting resources.
- Sonoma State Astronomy Links: Dozens of pages recommended by Dr. Joseph Tenn of the Sonoma Physics & Astronomy Department.
- Everglades Astronomical Society: Resources for people of all skill levels and even some smartphone apps that teach astronomy.
- Carrick: Astronomy based tools and resources for you to use.
- Daylight Chart: Free, downloadable program that allows users to display, customize, save and print, sunrise and sunset charts for a whole year at any location in the world.
- Day and Night World Map: See what parts of the Earth are experiencing day light and in what parts it is nighttime.
Moon Phases and Positions
- Phases of the moon: Dates of the primary phases of the moon and a lunar eclipse calculator from the U.S. Naval Observatory
- Space & Earth Science: Learn about the moon and how the Earth interacts with it.
- Discover the Moon: A guide to the phases of the moon.
- Lunar Phases Applet: Use this tool to help track the movements of the moon and see which the moon is currently in.
- Lunar Calendar: Learn more about the lunar phases throughout the year.
- Western-Chinese Calendar Converter: A tool that can be used to better understand the western and Chinese lunar calendars.
- Moon Connection: Understanding what causes the phases of the moon.
Solar Energy Information
- Energy Sources: Information on solar energy from the United States Department of Energy.
- Solar Energy: Benefits of solar energy including studies and maps presented by the United States Department of the Interior Bureau of Land Management.
- Solar Energy Sites: List of several sites pertaining to Solar Energy.
Sun Position (Azimuth and Altitude)
- Altitude and Azimuth: Basic definition of the terms including diagrams.
- Solar Position Calculator: Use to calculate declination, solar zenith angle, Julian day, hour angle, equation of time, sunrise and sunset times, and daily and instantaneous extraterrestrial radiation values from the University of Oregon Solar Radiation Monitoring Laboratory.
- Patio Umbrellas: At the hottest and brightest part of the day, you may want to relax in the shade to stay cool.
- Azimuth/Altitude Demonstrator: Shows how altitude and azimuth define an object's position in the sky.
- The Sun & RV Airplanes: Resources pertaining to both engineering and sun calculation.
- Maritime Consultant: Maritime resources including info on boating, the Coast Guard and the sun.
- Sunrise Calculator: National Oceanic & Atmospheric Administration Sunrise Calculator
- WxCam Sunrise/Sunset/Twilight Calculator: Calculate civil/nautical, sunrise, sunset, and twilight for any earthly location by entering longitude and latitude.
- Sunset Computer: Compute sunrise, sunset & twilight for cities & airports worldwide with time zones.
- GAISMA: Interactive map that provides sunset, sunrise, dawn and dusk times for thousands of locations around the planet.