  We perform an analysis of ~80000 photometric measurements for the following
10 stars hosting transiting planets: WASP-2, -4, -5, -52, Kelt-1, CoRoT-2,
XO-2, TrES-1, HD 189733, GJ 436. Our analysis includes mainly transit
lightcurves from the Exoplanet Transit Database, public photometry from the
literature, and some proprietary photometry privately supplied by other
authors. Half of these lightcurves were obtained by amateurs. From this
photometry we derive 306 transit timing measurements, as well as improved
planetary transit parameters.
  Additionally, for 6 of these 10 stars we present a set of radial velocity
measurements obtained from the spectra stored in the HARPS, HARPS-N, and SOPHIE
archives using the HARPS-TERRA pipeline.
  Our analysis of these TTV and RV data did not reveal significant hints of
additional orbiting bodies in almost all of the cases. In the WASP-4 case, we
found hints of marginally significant TTV signals having amplitude 10-20 sec,
although their parameters are model-dependent and uncertain, while radial
velocities did not reveal statistically significant Doppler signals.
