Visible-light astronomy Visible-light astronomy Visible-light astronomy encompasses a wide variety of observations via telescopes that are sensitive in the range of visible light (optical telescopes). Visible-light astronomy is part of optical astronomy, and differs from astronomies based on invisible types of light in the electromagnetic radiation spectrum, such as radio waves, infrared waves, ultraviolet waves, X-ray waves and gamma-ray waves. Visible light ranges from 380 to 750 nanometers in wavelength. Visible-light astronomy has existed as long as people have been looking up at the night sky, although it has since improved in its observational capabilities since the invention of the telescope, which
Ultraviolet (Light My Way) it. "Ultraviolet" played a featured role during the encores of the group's 1992–1993 Zoo TV Tour, 2009–2011 U2 360° Tour, and the Joshua Tree Tour 2017. "Ultraviolet (Light My Way)" began as two different demos, one variously called "Ultraviolet" and "69" (which eventually evolved into the B-side "Lady with the Spinning Head") and an alternately arranged demo called "Light My Way". Over the course of the recording sessions, U2 added various overdubs to the song, but producer Brian Eno believed these additions negatively impacted the track. Eno aided the group in editing down the song, and he explained his assistance