Buying Guides
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Best Eyepieces for Each Planet
The focal length to use for Mercury through Neptune, planet by planet.
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Best Telescope Covers
Keep dust, dew and sun off your scope between observing sessions.
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Best Star Diagonals
Mirror or prism, 1.25 or 2 inch: the right diagonal for your scope.
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.
Latest
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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