Operation of the Near Infrared Sky Monitor at the South Pole

Abstract

The near infrared sky spectral brightness has been measured at the South Pole with the Near Infrared Sky Monitor (NISM) throughout the 2001 winter season. The sky is found to be typically more than an order of magnitude darker than at temperate latitude sites, consistent with previous South Pole observations. Reliable robotic operation of the NISM, a low power, autonomous instrument, has been demonstrated throughout the Antarctic winter. Data analysis yields a median winter value of the 2.4 µm (K_dark) sky spectral brightness of ~120 µJy arcsec^–2 and an average of 210 ± 80 µJy arcsec^–2. The 75%, 50%, and 25% quartile values are 270 ± 100, 155 ± 60, and 80 ± 30 µJy arcsec^–2, respectively.