Factors to Consider When Selecting a Stereo Microscope
Fact Sheet - NASA Spitzer Space Telescope
Fabrication of large secondary mirrors for astronomical telescopes
F1 The ray diagram for a simple astronomical refracting telescope is
F. Pont
f - USP
f - LSU Physics
f - LSU Physics
Eyles, Bunker, Ellis et al. astro-ph/0607306 Eyles, Bunker, Ellis et al
Eye – pieces (Oculars) and their Cardinal Points Paper: Optics
EYE LITE - Premier Electronics
Extreme Energy Events (EEE) – Science inside Schools The EEE
extra-terrestrial observatories
Extra Credit Activities: 
Exploring with Lenses - Cosmic Connections Workshop
Exploring the Universe and Our Origins - from Hubble to JWST!
Exploring the Universe
Exploring the physical properties of the first galaxies
Exploring the cosmos
EXPLORING SPECIAL RELATIVITY USING HIGH ENERGY
Exploring Space with an Astronaut