  TRAPPIST-1 is an ultra-cool dwarf that hosts seven known transiting planets.
We present photometry of the system obtained using three telescopes at ESO La
Silla (the Danish 1.54-m telescope and the 2.2-m MPI telescope) and Paranal
(Unit Telescope 1 of the Very Large Telescope). We obtained 18 light curves
from the Danish telescope, eight from the 2.2-m and four from the VLT. From
these we measure 25 times of mid-transit for four of the planets (b, c, f, g).
These light curves and times of mid-transit will be useful in determining the
masses and radii of the planets, which show variations in their transit times
due to gravitational interactions.
