  A promising method for detecting earth-sized exoplanets is the timing
analysis of a known transit. The technique allows a search for variations in
either the transit duration or the center induced by the perturbation of a
third body, e.g. a second planet or an exomoon. By applying this method, the
TASTE (The Asiago Search for Transit Timing variations of Exoplanets) project
will collect high-precision, short-cadence light curves for a selected sample
of transits by using imaging differential photometry at the Asiago 1.82m
telescope. The first light curves show that our project can achieve a
competitive timing accuracy, as well as a significant improvement of the
orbital parameters. We derived refined ephemerides for HAT-P-3b and HAT-P-14b
with a timing accuracy of 11 and 25 s, respectively.
