General

Space.com - A website dedicated to news regarding spaceflight, space science, and technology in general. Their articles are often written so even novices can understand them.

Space Weather Now - A NOAA web that describes solar wind and solar flares. It also provides continuous updates on the current solar wind and solar flare activity. Best if viewed every few days to see how it changes especially if a solar flare is occurring.

Heavens Above - If you’re interested in satellites or astronomy, this is the right place! Their aim is to provide you with all the information you need to observe satellites, the International Space Station, the Space Shuttle, the dazzlingly bright flares from Iridium satellites, as well as a wealth of other space flight and astronomical information.

Telescopes for Kids - Astronomy resources for kids. Provides tips on finding your first telescope, how telescopes work, where to star gaze, and other astronomy stuff for kids!

Space Flight

NASA (National Aeronautics and Space Administration) - The home site of NASA, including information about the most recent space shuttle expeditions.

European Space Agency - Our friends on the other side of the puddle have a space agency too! The ESA had sponsored many astronauts who have flown aboard Mir and the International Space Station. Other interesting projects completed by ESA include Mars Express, Venus Express, and the Huygens probe which landed on the surface of Titan.

JPL Current Missions - A web site that describes the past, present and future spacecrafts that JPL is working on.

JPL Basics of Space Flight - This website provides a basic guideline for how a spacecraft is conceived, designed and operated. It begins with describing the environment of outer space and the difficulties that must be overcome. It then describes what is involved in the design and build of a spacecraft. Finally, it discusses the operations that take the spacecraft from launch to encounter.

Cassini-Huygens Mission Homepage - Launched in 1997, this spacecraft is currently studying Saturn and its moons. Cassini has already made several important discoveries. These include newly discovered moons, possible lakes on Titan, and an atmosphere on Enceladus.

New Horizons Mission Homepage - The New Horizons Spacecraft will be the first probe to take pictures of everyone’s favorite dwarf planet, Pluto. Launched in 2006, New Horizons won’t complete its long journey to Pluto until 2015. The probe has been studying Jupiter after a recent gravity assist from the gas giant.

Mars Rovers Mission Homepage - Mars Exploration Rovers Spirit and Opportunity have been busy crawling the red planet for years, far exceeding their 90 day “warranty”. The mission homepage has frequent updates from the flight controllers as well as all the recent photographs taken from the surface of Mars.

Space Flight Now - This is the definitive website for news and information regarding current space vehicle launches. Important launches such as shuttle missions often have minute-by-minute updates. Unfortunately the videos are for subscribers only.

Software

Stellarium - Have you ever looked up at the sky and wondered which night sky objects you were looking at? Stellarium solves this problem by creating a virtual backyard on your computer screen with all the stars, planets, and constellations clearly identified. It even lets you fast forward or rewind so you can get a good idea of what will be visible tonight. Stellarium is completely free and available for all major operating systems.

Celestia - Unlike Stellarium, Celestia lets you visit all those planetary objects up close. This 3D simulator will take you to any desired location in the universe. Check out the Screenshot Gallery for a sample of what Celestia can do. Like Stellarium, Celestia is completely free and works on Windows and OS X.

Interplanetary Objects

Wikipedia: Solar System - This Wikipedia entry has the complete guide to every notable object in the solar system.

The Eight Planets - A Multimedia Tour of the Solar System - An overview of the history, mythology, and current scientific knowledge of each of the planets and moons in our solar system. Each page has text and images, some have sounds and movies, most provide references to additional related information.

Moon Watch - A succinct site that offers all the technical information about the moon, earth’s closest neighbor. Updated on a daily basis.

In Constant Moon - Explore the Moon... discover its dramatic features and phenomena - often beautiful, sometimes bizarre, always changing. In constant Moon will take you on a new tour each night, with maps, photos, explanations, animations, selected links and even music!

Solar and Heliospheric Observatory Homepage (SOHO) - The SOHO spacecraft has been observing the sun from the L1 Lagrangian point since 1996. Every day the website updates itself with the latest pictures of our nearest star. The 11 year solar activity cycle is currently at a minimum, so not many sunspots will be visible for at least a few years.

Cruithne - This website has information about Cruithne, an asteroid which has an interesting 1:1 orbital resonance with Earth. Cruithne isn’t a real moon, since it is not gravitationally bound to the earth, but it is still sometimes called “Earth’s second moon”. The neatest features of this website are the orbital simulations on the right, which can be activated by clicking on them.

Astrophotography

Astronomy Picture of the Day - In conjunction with NASA and the Goddard Flight and Space Center, this site offers an image from space, updated daily.

Astronomy Picture of the Day Archive - If one picture a day isn’t enough, here is the entire archive of APOD entries!

Catching the Light - An astrophotography website put together by Jerry Lodriguss. Here you will find a beautiful digital photograph showcase showing both deep sky and wide angle shots. There is also information for those wishing to dive into the hobby of astrophotography.