I've just started studiyng Astronomy.
I understood how I would measure Right Ascention and Declination: for the first one I'd trace an Hour cirlce to the Celestial Equator, and then, compute the angle from this point and the Vernal Equinox; while the second one is the angle subtended by the object and the intersection of the Hour Circle with the Celestial Equator.
So, during the night, stars will change their Right Ascension value? Does this means this coordinate system is not fixed with respect to the stars?
If so, why people store the RA/Dec to find objects? For instance, I know the RA/Dec of the NGC 5585 Galaxy ( http://en.wikipedia.org/wiki/NGC_5585 ), but how can I use this information, if the RA changes during the night?