Optics and Astronomy links
Activity to identify materials in spectrum
Galileoscope assembly and use
Sky map program
Excelent photographs of the Hubble Space Telescope
Spectrometry information and activities
Renu Malhotra, profesora e investigadora de astronomía
The National Space Society of Phoenix
Planetary Habitability Laboratory at UPR Arecibo
NASA Solar System
Scholarpedia
Solar Dynamics Observatory
A Teacher’s Guide to the Universe
The Physics Factbook
Atlas del Universo
Astronomy education U Nebraska-Lincoln
Hubble site
Heaven above
3D Test (Video)