Astronomy
Explore the cosmos from K-12 to PhD research with 2500+ curated resources from NASA, ESA, and institutions worldwide. Free textbooks, observational guides, planetarium software, and research tools.
Featured Resources
NASA Official Portal
NASA
America's space agency with missions, research, and educational resources
ESA - European Space Agency
ESA
Europe's gateway to space with extensive science and exploration content
Hubble Space Telescope
NASA/ESA/STScI
Breathtaking images and discoveries from the legendary space telescope
Sky & Telescope Magazine
AAS
Premier astronomy magazine with observing guides and space news
Astronomy Magazine
Kalmbach Media
Popular astronomy magazine for amateur and professional astronomers
Stellarium Web
Stellarium Project
Free open-source planetarium for your computer and mobile devices
K-12 School Resources
Astronomy resources for primary and secondary school students
NASA for Students
NASA
Games, activities, and resources for young astronomers
ESA Kids
ESA
Space adventures and fun facts for children
NASA Space Place
NASA
Games, animations, and projects about space and Earth science
Crash Course Astronomy
Crash Course
46-episode comprehensive astronomy course by Phil Plait
Astronomy Picture of the Day
NASA
Discover the cosmos with a new image every day
StarChild
NASA GSFC
Learning center for young astronomers
Imagine the Universe
NASA GSFC
High school astronomy and astrophysics resources
Planet Hunters
Zooniverse
Help discover new planets by analyzing NASA data
NASA Kids' Club
NASA
Games and activities for young space explorers
ESA Kids - Paxi
ESA
Paxi the alien teaches kids about space
Amazing Space
STScI
Space telescope science institute educational resources
Night Sky Network
NASA/JPL
Amateur astronomy clubs bringing science to the public
Astronomical Society of the Pacific
ASP
Education and outreach resources for astronomy
Royal Astronomical Society of Canada
RASC
Canadian astronomy education and observing resources
British Astronomical Association
BAA
UK organization for amateur astronomers
Society for Popular Astronomy
SPA
UK society making astronomy accessible to everyone
Sky & Telescope Magazine
AAS
Premier astronomy magazine with observing guides
Astronomy Magazine
Kalmbach
Popular astronomy magazine for all levels
NASA's Eyes
NASA
Immersive 3D simulations of NASA missions
SciJinks
NASA/NOAA
Weather and Earth science for middle schoolers
Free Textbooks
Comprehensive astronomy textbooks organized by level
Beginner / High School Level
Astronomy
OpenStax
Comprehensive introductory astronomy textbook
21st Century Astronomy
Kay et al.
Introductory astronomy with active learning
The Cosmic Perspective
Bennett et al.
Popular introductory astronomy text
Exploring the Universe
Palen et al.
Introductory astronomy for non-science majors
Intermediate / Undergraduate Level
An Introduction to Modern Astrophysics
Carroll & Ostlie
Standard undergraduate astrophysics text (The "BOB" book)
Fundamentals of Astrophysics
Stan Owocki
Concise introduction to astrophysical concepts
Astrophysics of Stars
Nadia Langer
Stellar structure and evolution
Extragalactic Astronomy and Cosmology
Peter Schneider
Galaxies and cosmology for undergraduates
Advanced / Graduate Level
Gravitation
Misner, Thorne & Wheeler
The definitive text on general relativity
Radiative Processes in Astrophysics
Rybicki & Lightman
Essential reference for radiative transfer
Galactic Dynamics
Binney & Tremaine
The standard text on stellar dynamics
Astrophysics of the Interstellar Medium
Draine
Comprehensive interstellar medium physics
Observational Astronomy Resources
Tools and guides for amateur and professional observers
Sky & Telescope
AAS
Observing guides, equipment reviews, and sky charts
Astronomy Magazine
Kalmbach
Star charts and observing tips for all levels
Heavens-Above
Chris Peat
Satellite passes, ISS tracking, and sky charts
In-The-Sky.org
Dominic Ford
Interactive sky map and astronomical events
TimeAndDate Night Sky
TimeAndDate
Planets visible tonight and meteor showers
Clear Sky Chart
Attilla Danko
Astronomical weather forecasts for observing sites
Telescope Reviews
Cloudy Nights
Telescope reviews and amateur astronomy forums
American Association of Variable Star Observers
AAVSO
Variable star observation and data archives
Astronomical League
AL
Federation of amateur astronomy societies
Messier Catalog
SEDS
Complete guide to the Messier objects
Astrophysics Resources
Research tools, data analysis software, and academic resources
arXiv Astrophysics
Cornell
Latest astrophysics research papers
ADS Astrophysics Data System
NASA/SAO
Abstracts and full-text of astronomy papers
AstroBetter
Astronomy Community
Tips and tricks for astronomers
Python for Astronomers
Astropy
Core package for astronomy in Python
Astrophysics Source Code Library
ASCL
Free astronomy software source codes
NED - NASA/IPAC Extragalactic Database
NASA/IPAC
Data for extragalactic objects
HEASARC
NASA GSFC
High-energy astrophysics data archive
LIGO Scientific Collaboration
LIGO/Virgo
Gravitational wave astronomy resources
Space Exploration Resources
Space agencies, companies, and mission updates
SpaceX
SpaceX
Revolutionary space technology and missions
Blue Origin
Blue Origin
Reusable rockets and space tourism
Rocket Lab
Rocket Lab
Small satellite launch services
ISRO - India Space Research
ISRO
India's ambitious space program
CNSA - China National Space
CNSA
China's growing space exploration efforts
JAXA - Japan Aerospace
JAXA
Japan's space and planetary science missions
Roscosmos
Russia
Russian Federal Space Agency
SpaceNews
SpaceNews
Daily news on space industry and policy
Planetary Society
TPS
Space advocacy and education nonprofit
Space.com
Future plc
Latest space news and mission updates
Planetarium Software & Tools
Desktop, web, and mobile applications for exploring the night sky
Stellarium
Open Source
Free open-source planetarium software
Celestia
Open Source
Real-time 3D space simulation
WorldWide Telescope
Microsoft/AAS
Universe visualization from your browser
Aladin Sky Atlas
CDS Strasbourg
Interactive sky atlas for astronomers
KStars
KDE
Desktop planetarium for KDE/Linux
Cartes du Ciel
Patrick Chevalley
Free sky charting software
Nightshift
Nightshift
Stargazing app with AR features
Star Walk 2
Vito
Interactive stargazing guide
SAOImage DS9
Smithsonian/CfA
Astronomical imaging and data visualization
TOPCAT
Bristol University
Tool for operations on catalogs and tables
STILTS
Bristol University
Command-line tools for table manipulation
SpaceEngine
Cosmographic Software
Free universe simulator with photorealistic graphics
Universe Sandbox
Giant Army
Interactive space gravity simulator
SkySafari
Simulation Curriculum
Professional planetarium app for mobile
Star Walk
Vito
Stargazing guide with augmented reality
Star Chart
Escapist Games
Star mapping app for iOS and Android
StarTracker
Shenya
Mobile sky map with AR mode
SkyView
Terminal Eleven
Point device to identify objects in the sky
Exoplanet
Hanno Rein
Interactive catalog of exoplanets
LunarMap
Christian Legrand
Detailed lunar visualization software
Data Archives & Databases
Essential astronomical databases and mission archives for research
SIMBAD
Strasbourg astronomical database with 12+ million objects
VizieR
Astronomical catalog archive with 20,000+ catalogs
NASA ADS
Astrophysics Data System with 15+ million papers
NED
NASA/IPAC Extragalactic Database
MAST
Mikulski Archive for Space Telescopes (Hubble, TESS, etc.)
HEASARC
High Energy Astrophysics Science Archive
IRSA
NASA/IPAC Infrared Science Archive
NASA Exoplanet Archive
Comprehensive exoplanet data and tools
SDSS
Sloan Digital Sky Survey - millions of spectra and images
2MASS
Two Micron All Sky Survey catalog
Gaia Archive
ESA Gaia mission with 1.8 billion star catalog
Pan-STARRS
Panoramic Survey Telescope and Rapid Response System
Hubble Legacy Archive
Enhanced Hubble data products and images
JWST Data Archive
James Webb Space Telescope archive
Chandra Data Archive
X-ray observatory data archive
XMM-Newton Science Archive
ESA X-ray observatory data
ESO Science Archive
European Southern Observatory data
ALMA Science Portal
Atacama Large Millimeter/submillimeter Array data
LAMBDA
Legacy Archive for Microwave Background Data Analysis
Planck Archive
Planck satellite CMB data
Kepler/K2 Data
Kepler and K2 mission exoplanet data
TESS Data
Transiting Exoplanet Survey Satellite data
WFC3 Library
Hubble Wide Field Camera 3 data
VLA Archive
Very Large Array radio astronomy data
ATNF Pulsar Catalogue
Comprehensive pulsar database
ExoMol
Molecular spectroscopy for exoplanets
Atomic Spectra Database
Atomic spectra and transition data
CDS Portal
Strasbourg astronomical data center portal
VOSA
Virtual Observatory SED Analyzer
Astroquery
Python access to online astronomical data
Observatories & Telescopes
Ground and space-based astronomical observatories worldwide
Ground-Based Optical/IR Telescopes
Keck Observatory
Twin 10-meter telescopes on Mauna Kea
Very Large Telescope (VLT)
ESO's four 8.2m telescopes at Paranal
Gran Telescopio Canarias
10.4m telescope - world's largest optical
Subaru Telescope
8.2m Japanese telescope on Mauna Kea
Gemini Observatory
Twin 8.1m telescopes in both hemispheres
SALT
Southern African Large Telescope - 11m
Hobby-Eberly Telescope
9.2m telescope at McDonald Observatory
Magellan Telescopes
Twin 6.5m telescopes at Las Campanas
Large Binocular Telescope
Twin 8.4m mirrors on Mount Graham
Palomar Observatory
Home of the famous 200-inch Hale Telescope
Lick Observatory
Historic observatory on Mount Hamilton
Kitt Peak National Observatory
US national optical astronomy observatory
Cerro Tololo Inter-American
Major Southern Hemisphere observatory
La Palma Observatory
Roque de los Muchachos Observatory
Future Telescopes
Space Telescopes
Hubble Space Telescope
Legendary 30-year observatory in orbit
James Webb Space Telescope
Infrared successor to Hubble
Chandra X-ray Observatory
X-ray telescope studying high-energy universe
TESS
Transiting Exoplanet Survey Satellite
Gaia
Mapping 1.8 billion stars in 3D
XMM-Newton
X-ray Multi-Mirror Mission
Integral
Gamma-ray observatory
Fermi Gamma-ray Telescope
Gamma-ray burst and pulsar hunter
NuSTAR
Nuclear Spectroscopic Telescope Array
Swift
Gamma-ray burst rapid response
WISE
Wide-field Infrared Survey Explorer
Herschel Space Observatory
Far-infrared space observatory (2009-2013)
Planck
Cosmic microwave background mapper
Kepler/K2
Revolutionary exoplanet hunter mission
Radio Telescopes
ALMA
Atacama Large Millimeter/submillimeter Array
Very Large Array (VLA)
27 antennas on the Plains of San Agustin
FAST
Five-hundred-meter Aperture Spherical Telescope
Effelsberg 100m
Max Planck 100-meter radio telescope
Green Bank Telescope
World's largest fully steerable radio dish
Parkes Telescope
Murriyang - iconic 64-meter dish
Jodrell Bank
Lovell Telescope and observatory
LOFAR
Low-Frequency Array - thousands of antennas
MeerKAT
64-dish precursor to SKA
Square Kilometre Array
World's largest radio telescope under construction
Space Agencies
National and international space organizations worldwide
NASA
National Aeronautics and Space Administration
ESA
European Space Agency - 22 member states
JAXA
Japan Aerospace Exploration Agency
ISRO
Indian Space Research Organisation
CNSA
China National Space Administration
ROSCOSMOS
Russian Federal Space Agency
CSA
Canadian Space Agency
ASI
Italian Space Agency
CNES
Centre National d'Études Spatiales
DLR
German Aerospace Center
UKSA
UK Space Agency
KARI
Korea Aerospace Research Institute
Citizen Science Projects
Contribute to real astronomy research from home
Galaxy Zoo
Classify galaxies by shape and morphology
Planet Hunters TESS
Find exoplanets in TESS data
Backyard Worlds
Discover brown dwarfs and rogue planets
Radio Galaxy Zoo
Classify radio galaxies and black holes
Space Warps
Find gravitational lenses
Disk Detective
Identify debris disks around stars
Milky Way Project
Map star formation in our galaxy
Planet Four
Map surface features on Mars
Online Courses
Free and paid astronomy courses from leading institutions
Coursera Astronomy
University astronomy courses from top institutions
edX Astronomy (ANU)
Astrophysics courses from ANU and University of Arizona
Khan Academy Cosmology
Free cosmology and astronomy lessons
FutureLearn Astronomy
Astronomy courses from UK universities
Swayam Astronomy
Free Indian government astronomy courses
OpenLearn Astronomy
Free UK Open University courses
CosmoLearning Astronomy
Free astronomy video courses
Astronomy MOOCs
Directory of online astronomy courses
Research & Journals
Academic journals and research resources for astronomy and astrophysics
The Astrophysical Journal
Premier journal for astrophysics research (ApJ)
Astronomy & Astrophysics
Leading European astronomy journal (A&A)
Monthly Notices of the RAS
Royal Astronomical Society journal (MNRAS)
The Astronomical Journal
Observational astronomy research (AJ)
Nature Astronomy
High-impact astronomy and astrophysics
Science Astronomy
Broad-interest astronomy papers
Physical Review D
Gravitational physics and cosmology
Journal of Cosmology
Astroparticle physics and cosmology (JCAP)
Astrobiology
Origin and evolution of life in the universe
Publications of the ASP
Astronomical Society of the Pacific (PASP)
Classical and Quantum Gravity
Gravitational physics journal
General Relativity and Gravitation
Gravitational physics research
Solar Physics
Solar and heliospheric research
Icarus
Planetary science journal
Planetary Science Journal
PSJ - Planetary research journal
New Astronomy
Astronomy and astrophysics research
Research in Astronomy & Astrophysics
RAA - Chinese astronomy journal
Journal of Astrophysics and Astronomy
Indian Academy of Sciences journal
Publications of the ASJ
Astronomical Society of Japan (PASJ)
Chinese Astronomy & Astrophysics
Chinese astronomy translations
Astronomische Nachrichten
German astronomy journal (AN)
Experimental Astronomy
Instrumentation and methods
High Energy Density Physics
Laboratory astrophysics
Living Reviews
Living Reviews in Relativity and Solar Physics
Universe
Multidisciplinary astronomy journal
Galaxies
Galaxy research open access
Symmetry
Physics and mathematics open access