Q:  The stars Mintaka and Sadalmelik are both very close to
           the celestial equator; in other words, their Declinations
           are both very close to zero.

           Look up their Right Ascension values.  What is the angular
           distance between the two stars, measured in degrees?


            Mintaka:       RA = 05:32:00        Dec = -00:17:57
            Sadalmelik:         22:05:47              -00:19:11


           Let's first convert the RA values to decimal hours:

            Mintaka:            5 + (32/60) + (00/3600)  =   5.533333   hours
            Sadalmelik:        22 + ( 5/60) + (47/3600)  =  22.096389   hours

    
           and now to decimal degrees:

            Mintaka:            (5.5333333 hours) * (15 degrees/hour)    =   83.0000  degrees
            Sadalmelik:         (22.096389 hours) * (15 degrees/hour)    =  331.4458  degrees
    

           Now we can compute the difference in their RA values:

              delta_ra   =  331.4458  -  83.0000    =  248.446   degrees


           This is not incorrect ... but it's not the answer one would usually provide.
           If we start at Mintaka, and move east across the sky in the direction of
           increasing RA, then it will take about 248 degrees to reach Sadalmelik.
           But 248 degrees is more than half-way around a complete circle!

           Instead, if we start at Mintaka and move _west_ across the sky, in the
           direction of _decreasing_ RA, then we reach RA = 0 ... but that's the same
           as RA = 360.  If we keep going in the negative RA direction, we'll quickly
           reach the position of Sadalmelik at RA = 331 degrees.

           In this direction, the distance between the stars is just
 
              delta_ra   =   360 degrees - 248.446 degress  =  111.554 degrees