[Chimera-users] measure crossing angles for axes

I have used the "measure rotation" command to create several axes. In each case, a marker set (to show the axis) is generated that consists of 2 pseudoatoms and 1 bond. Is there a simple way to measure the crossing angle between 2 such axes? If the marker set had 3 atoms, I could probably use the Axes/Planes tools to do this. Thanks, Tom