- The American Association of Amateur Astronomers
- The Internet Astronomy Club - Bringing Amateur Astronomy to the World
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- American Association of Variable Star Observers
- The American Association of Variable Star Observers (AAVSO) is a non-profit worldwide scientific and educational organization of amateur and professional astronomers who are interested in stars that change in brightness — variable stars.
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- International Astronomical Union (IAU)
- The International Astronomical Union (IAU)
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- Sunrisesunset
- Custom Sunrise Sunset Calendar
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- Skymaps
- Sky Maps Each Month
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