Supergalactic cartesian coordinate system - a simple definition<BR>
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Supergalactic cartesian coordinate system is, just as is visible from its 
name, a cartesian version of the supergalactic coordinate system. To 
calculate supergalactic SGX, SGY, and SGZ one has to know the coordinates 
of an object in some other system and also its distance to the origin of that 
coordinates system. By definition the direction of SGX has values SGL = 0 deg, 
SGB = 0 deg, that of SGY has SGL = 90 deg, SGB = 0 deg, and that of SGZ has 
SGL = 0 deg, SGB = 90 deg.<BR>
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