  Instrumental data are affected by systematic effects that dominate the errors
and can be relevant when searching for small signals. This is the case of the
K2 mission, a follow up of the Kepler mission, that, after a failure on two
reaction wheels, has lost its stability properties rising strongly the
systematics in the light curves and reducing its photometric precision. In this
work, we have developed a general method to remove time related systematics
from a set of light curves, that has been applied to K2 data. The method uses
the Principal Component Analysis to retrieve the correlation between the light
curves due to the systematics and to remove its effect without knowing any
information other than the data itself. We have applied the method to all the
K2 campaigns available at the Mikulski Archive for Space Telescopes, and we
have tested the effectiveness of the procedure and its capability in preserving
the astrophysical signal on a few transits and on eclipsing binaries. One
product of this work is the identification of stable sources along the ecliptic
plane that can be used as photometric calibrators for the upcoming Atmospheric
Remote-sensing Exoplanet Large-survey mission.
