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 Telescopes for Teenagers
Real telescopes a teen can set up alone and keep using for years.
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Best Telescope Covers
Keep dust, dew and sun off your scope between observing sessions.
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
A neutron star is the collapsed core of a massive star that blew up as a supernova: about 1.4 times…
TLDR Table of contents What is an ocean planet? An ocean planet is a planet or moon with a global…
An interactive 3D Sun. See today’s real NASA image with NOAA’s sunspot regions pinned on it, then cut it open to explore the core, convection zone, photosphere, chromosphere and corona.
An interactive 3D model of three real comets: Halley, 67P and Tempel 1. Show the coma and tails, add mission sites, watch them spin and compare each nucleus with the Empire State Building.
An interactive 3D model of three real asteroids: Bennu, Apophis and Vesta. Add mission sites, watch them spin and compare each with the Empire State Building or Arizona.
A constellation identification game drawn from real star catalogue data. Three levels, 10 questions a round, from Orion and the Big Dipper to all 88 constellations.
Your weight, age, next birthday and jump height on every planet, the Moon, Pluto and the Sun, with the formulas worked out.
When is the next solar and lunar eclipse, and can you see it from where you live? Live countdown, local times, path maps and the full eclipse calendar.
New content!
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