We present a summary of the campaign of remote observations that
supported the European Space Agency's Rosetta mission. Telescopes across
the globe (and in space) followed comet 67P/Churyumov-Gerasimenko from
before Rosetta's arrival until nearly the end of mission in September
2016. These provided essential data for mission planning, large-scale
context information for the coma and tails beyond the spacecraft, and a
way to directly compare 67P with other comets. The observations revealed
67P to be a relatively `well behaved' comet, typical of Jupiter family
comets and with activity patterns that repeat from orbit-to-orbit.
Comparison between this large collection of telescopic observations and
the in situ results from Rosetta will allow us to better understand
comet coma chemistry and structure. This work is just beginning as the
mission ends -- in this paper we present a summary of the ground-based
observations and early results, and point to many questions that will be
addressed in future studies.
- Astrophysics - Earth and Planetary Astrophysics