1. IR Cloud Camera D. Burke DES Calibration Telecon May 13, 2009

2. 2 Atmospheric IR Windows DeSolver, et al.(1999)

3. 3 IR Emissivity vs IR Optical Depth Mahesh, et al. Part II (2001)

4. 4 Visible to IR Depth Ratio DeSolver, et al (1999) Visible at 532 nm.

5. 5 Contrast and Equivalent Noise Clear sky radiance (U.S. Standard Atmosphere) ~ 3x10 -3 Wm -2 /cm -1 /sr ( This corresponds to a temperature of about 150K.) Thin (visible optical depth 0.01) cirrus at 900cm -1 and 245K R cloud (visible) = IR emissivity * blackbody (IR; 245K) ~ 4X10 -4 Wm -2 /cm -1 /sr → Contrast of 15% in radiance against 150K thermal background. → Temperature difference of 2K at 150K → NETD 120mK at 300K.

6. 6 Commercial Thermal Cameras FLIR Systems (www.flir.com) Long IR model –GaAS Quantum Well IR Photodiode (8.0-9.2  m) Up to 640x512 array format Lens option: 500mm lens → 1.8x1.5 sq deg. FOV → 0.17 arcminute / pixel resolution < 35 mK (NETD) Standard Frame Rate FLIR SC6000 (S/N = 1 at 126Hz?)  Co-bore sight with DECam?