Buying Guides
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Best Reflector Telescopes for Beginners
The most aperture for your money, chosen for a first telescope.
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Best Budget Telescope Eyepieces
Affordable eyepieces that beat the ones bundled with your scope.
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Best Eyepieces for Dobsonians
Eyepieces matched to the fast focal ratios of Dobsonian telescopes.
Free Resources
Space Printables
Free PDF quizzes and worksheets for kindergarten to adult, with answer keys.
3D Space Models
Spin real maps of the Moon and planets built from NASA data. Find craters, landing sites, the rings of Saturn, Uranus and Neptune and the moons of Jupiter.
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Germany gave astronomy its planetary laws, its first measured star distance, the sighting of Neptune and the first picture of…
On August 15, 1977, a radio telescope in Ohio recorded 72 seconds of a narrow, powerful signal near the hydrogen…
Around 105 women have flown to space. Out of everyone who has ever left the planet, that’s fewer than 15%.…
Gravitational lensing happens when matter sits between a distant light source and you, and its gravity bends the light on…
Contents TLDR: which planetarium should you visit? Arkansas has few planetariums, and fewer of them take walk-ins. Here is the…
TLDR Table of contents Canada has a small astronomy community and a long list of results that people outside Canada…
Contents What is a binary star? A binary star is a pair of stars held together by gravity, each orbiting…
A neutron star is the collapsed core of a massive star that blew up as a supernova: about 1.4 times…
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