Hubblecast 21 Special: From silver to silicon

Observing the Universe through the eyepiece of a telescope is one thing, but recording the observations for posterity is something quite different. Originally astronomers used pen and paper to draw what they saw, but the human eye is a lousy detector and our brain can play tricks on us. Astrophotography, first explored in the mid-nineteenth century, has proved to be a powerful, objective way of recording telescopic images with the advantage that long exposures revealed much more than the eye could ever see. But the true revolution arrived with electronic detectors and digital image processing. More on: http://www.spacetelescope.org/videos/html/hubblecast21a.html