There is much potential for the use of light-emitting diodes in a light-weight orbiting microscope. Here the available LED's are assessed for light contour and intensity. A customised grid was designed, so that the light path could be objectively measured. Of the LED's currently available, one emitting apple-green light proved to be the brightest and has the best focussed beam. This is the wavelength currently used for the calibration of achromatic lens systems (used in microscopes). Since the sensor is not colour sensitive, this fortunate coincidence gives the best source of illumination for a modern microscope.
Go to next phase.