Specifications and  Performance

Present Specifications

Array diameter 54 m
Filling factor 0.71
Effective area 1414 m2 (42.4 m equivalent diameter)
Element diameter 10 m f/2.5
Beam combiner Fizeau imaging interferometer
Pointing range up to 4 degrees from zenith
Instantaneous field of view 1 arcmin diameter
Tracking time up to 30 min
Wavelength range 0.5 - 2.5 um
Detector Simultaneous Optical/IR (VRIJHK) imagers
Pixel size (coherent mode) Optical camera:  1.0 mas (Nyquist at 0.6 um)
IR camera:         2.0 mas (Nyquist at 1.2 um)
Pixel size (incoherent mode) Optical camera:  6.0 mas (Nyquist at 0.6 um)
IR camera:       12.0 mas (Nyquist at 1.2 um)
Minimum detector size Optical camera: 4096 x 4096
IR camera:        2048 x 2048
 

Point-Source Limiting Magnitudes (AB scale)

 

Incoherent mode

Coherent mode
Integ. time 10s 600s 45000s 10s 600s 45000s
V 25.2 27.4 29.8 26.8 29.0 31.4
R 29.1 32.3 34.6 31.6 33.9 36.2
I 30.1 32.3 34.6 31.6 33.8 36.2
J 30.1 31.1 33.4 30.4 32.7 35.0
H 28.1 30.3 32.7 29.7 31.9 34.2
K 27.6 29.8 32.2 29.2 31.4 33.7
 

Reflectivity and Emissivity of Mercury

Wavelength (um) Reflectivity Emissivity
0.316 0.749 0.251
0.398 0.756 0.244
0.501 0.762 0.238
0.631 0.769 0.231
0.794 0.776 0.224
1.000 0.784 0.216
1.259 0.794 0.206
1.598 0.805 0.195
1.995 0.817 0.183
2.512 0.829 0.171
3.162 0.842 0.158
3.981 0.855 0.145
5.012 0.867 0.133
6.310 0.879 0.121
7.943 0.890 0.110
10.000 0.901 0.099
12.589 0.910 0.090
15.849 0.919 0.081
19.953 0.927 0.073
25.119 0.935 0.065
31.623 0.941 0.059

Calculated using the Drude dispersion formula fitted to the experimental data of Boiani & Rice (Phys Rev 185, 931, 1969) and Boloch & Rice (Phys Rev 185, 933, 1969)

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Last updated: 2002/09/12