Characterization of narrow band filters for infrared astronomy - The Br gamma and H-2 filters

We present a characterization of two narrow band filters commonly used in Infrared Astronomy. Our study mainly quantifies the effect of temperature and tilt angle on the central wavelength and width of the transmission bands of such filters. This allows to evaluate some important effects that must be taken into account to have good quality astronomical images. Effects as the limitation of the field of view and the presence of OH sky lines in the final image are quantified.