Galactic coordinate system - a simple definition<BR>
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For studies of more distant galactic objects or somewhat closeby 
extragalactic objects, a natural reference plane is the plane of the Milky 
Way. Since the Sun lies very close to that plane, we can put the origin at 
the Sun.<BR>
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Galactic longitude, l, is measured counterclockwise from the direction of 
the centre of the Milky Way (in Sagittarius, R.A. = 17h 45.7min, dec. = 
-29 deg). The values are between 0 and 360 degrees in decimal format 
(degrees).<BR>
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Galactic latitude, b, is measured from the galactic plane, positive 
northwards and negative southwards. The values are between -90 and +90 
degrees in decimal format (degrees).<BR>
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