Now we know how to measure an object's right ascension, but we still don't know where to start measuring. Unlike the local coordinate system where we have a definite starting point (north), there is no special place like that along the celestial equator

So, what did the astronomers do? They made one up! The starting point from which we measure right ascension is called the vernal equinox—a fixed point along the celestial equator where it intersects the yearly path of the sun through the sky.

So now, the process of determining an objects position in the sky is simple: Measure the number of hours, arc minutes, and arc seconds along the celestial equator from the vernal equinox to get the right ascension and then up or down the number of degrees, minutes, and seconds to get the declination! Of course, if you want to find this object in your own backyard, you have to know where the celestial equator and the vernal equinox are compared to your current location. It is for this reason that the equatorial coordinate system is most often used with tools such as telescopes where it is easy to keep track of where you are looking.