  ASTRONIRCAM is an infrared camera-spectrograph installed at the 2.5-meter
telescope of the CMO SAI. The instrument is equipped with the HAWAII-2RG array.
A bad pixels classification of the ASTRONIRCAM detector is proposed. The
classification is based on histograms of the difference of consecutive
non-destructive readouts of a flat field. Bad pixels are classified into 5
groups: hot (saturated on the first readout), warm (the signal accumulation
rate is above the mean value by more than 5 standard deviations), cold (the
rate is under the mean value by more than 5 standard deviations), dead (no
signal accumulation), and inverse (having a negative signal accumulation in the
first readouts). Normal pixels of the ASTRONIRCAM detector account for 99.6% of
the total. We investigated the dependence between the amount of bad pixels and
the number of cooldown cycles of the instrument. While hot pixels remain the
same, the bad pixels of other types may migrate between groups. The number of
pixels in each group stays roughly constant. We found that the mean and
variance of the bad pixels amount in each group and the transitions between
groups do not differ noticeably between normal or slow cooldowns.
