Photometric Operation Mode of the ASTRONIRCAM Camera

We explain the details of the photometric operation mode of the ASTRONICAM near-IR spectrograph camera mounted on the 2.5-m telescope of the Caucasian Mountain Observatory of the Sternberg Astronomical Institute and describe algorithms used for primary correction and overall pipeline reduction of the acquired data. We present the transformation equations from the 2MASS photometric system to the instrumental Y -band system. We derive color transformation coefficients between the instrumental photometric system and standard MKO-NIR (Mauna Kea Observatories Near-Infrared) system for the J , H , and K -band filters and show that the camera system is close to the standard photometric system. We found that in the case of observations at zenith, average background brightness level, and 1^'' seeing the stars with J=22^m , H=20m.5 , K=19m.5 can be measured with a 3000-s exposure at the signal-to-noise ratio SNR=3 .