INTRODUCTION
"Until the development of radio astronomy in the 1940's, our view of the Universe was confined to the narrow visible-light window. However, there is more to the Universe than meets the eye. In addition to the light emitted by stars, galaxies, quasars and other celestial objects, there is invisible energy - infrared and ultraviolet light, x-rays and radio - that our eyes cannot detect. Special telescopes are needed to "see" this invisible radiation. Unfortunately, other than optical light, only radio waves are easily seen from the Earth's surface." ~
http://us-space-vlbi.jpl.nasa.gov/
Very Long Baseline Interferometry makes use of this radio energy. Two or more Radio Observatories, electronically linked, systematically analyze an object. After setting the collected frequency data from both sites and setting them in phase, an astronomer now has a view of the object possible, by use of an optical telescope, only with a lens of a diameter that is the distance between the two observatories.
Until the development of this technique, the best information obtainable depended on optical telescopes. VLBI turned around a huge disadvantage of an inefficient data collecting process (compared to optical, radio telescopes were not as good) and revolutionized the future of Astronomy.
Under VLBI Space Observatory Program (VSOP --Japanese mission launched in 1997), Scientists built on the principles of VLBI to take advantage of the other electromagnetic spectra they can now reach by going beyond the earth's atmosphere. As well as the even longer distances. VSOP was the first of the Space VLBI space programs.
This site seeks to be an introduction to these tools.
