Use Grace (xmgr) to plot a color-magnitude diagram for the Pleiades from the
Johnson data. As a start, simply use the command
xmgr johnson_color.dat to create the data sets. To make a conventional
color-magnitude graph you will need to invert the y-axis (bright stars or
negative magnitudes are at the top), and to plot individual stars with a small
symbol rather than a line from point to point.