Q:  If one acquired a high-resolution spectrum of the entire
           range from 4000 to 6000 Angstroms, how many lines
           might one be able to measure?



       Based on a rough estimate of about 1 line per 0.3 Angstroms
           in the high-res spectrum, over a range of 2000 Angstroms,
           one might detect

                                               1 line
                N  =  2000 Angstroms  *  ( ---------------- )
                                             0.3 Angstroms

                   =  around 6600 lines!