section_path: Human presence/Astronomy from the Moon
section_name: Astronomy from the Moon
paragraph_text: Astronomy from the Moon
  
  The Moon is recognized as an excellent site for telescopes. It is relatively nearby; certain craters near the poles are permanently dark and cold and especially useful for infrared telescopes; and radio telescopes on the far side would be shielded from the radio chatter of Earth. The lunar soil, although it poses a problem for any moving parts of telescopes, can be mixed with carbon nanotubes and epoxies and employed in the construction of mirrors up to 50 meters in diameter. A lunar zenith telescope can be made cheaply with an ionic liquid.
  
  In April 1972, the Apollo 16 mission recorded various astronomical photos and spectra in ultraviolet with the Far Ultraviolet Camera/Spectrograph.
  
  The Moon has been also a site of Earth observation, particularly culturally as in the 1968 photograph called Earthrise, taken by Bill Anders of Apollo 8. The Earth appears in the Moon's sky with an apparent size of 1° 48 ′ to 2°, three to four times the size of the Moon or Sun in Earth's sky, or about the apparent width of two little fingers at an arm's length away.