[link to ssd.jpl.nasa.gov]
If I align this to view from above the suns poles when the comet is the same distance from the Sun as Earth the second time, these objects seem to be exactly aligned in a straight line and the comet is on top of Earth at the same time.
Mercury is on the otherside of the Sun, Venus is between the Sun and Earth Jupiter is on the other side of Earth and Comet Ison is on top of Earth.