IR Photometer PDF Print E-mail


 Decommissioned

The IR photometer built by the Infrared lab inc. is used at the cassegrain focus. It employs a InSb detector cooled to the criogenic temperature of liquid nitrogen. A chopper system allow a fast sampling of the telescope and sky background. The photometer is designed to work J, H, K, L, M, of the standard Johnson photometric system, but due to the low hight of the observatory and the characteristics of the telescope only the J, H, K filters can be used .


Filters   

band

λeq((µm)

Δλ (µm)

J

1.24

0.33

H

1.64

0.31

K

2.22

0.38

L

3.86

0.67

M

4.74

0.60

 
Both the diaphragm and filter wheels should be manually set, while the signal acquisition is made by means of the PC running the Obelix photometric acquisition software .


Limiting magnitude
7.5 in J, H, K

 

Mean atmospheric extinction coefficients

0.129 +/- 0.055 J

0.152 +/- 0.027 H

0.147 +/- 0.025 K