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AAOmega
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Grating Set, Dispersion, Spectral
Resolution
|
Name
|
Blaze
|
Useful wavelengths
|
Coverage
|
Angle
|
Dispersion
|
MOS Resolution
|
|
|
nm
|
nm
|
nm
|
Degrees
|
nm/pix
|
R
|
|
580V
|
450
|
370 to 580
|
210
|
8
|
0.1
|
1300
|
|
385R
|
700
|
560 to 880
|
320
|
8
|
0.16
|
1300
|
|
1700B
|
400
|
370 to 450
|
65
|
18
|
0.033
|
3500
|
|
1500V
|
475
|
425 to 600
|
75
|
20 - 25
|
0.037
|
3700
|
|
1000R
|
675
|
550 to 800
|
110
|
18 - 22.5
|
0.057
|
3400
|
|
1000I
|
875
|
800 to 950
|
110
|
22.5 - 25
|
0.057
|
4400
|
|
3200B
|
400
|
360 to 450
|
25
|
37.5 - 45
|
0.014
|
8000
|
|
2500V
|
500
|
450 to 580
|
35
|
37.5 - 45
|
0.018
|
8000
|
|
2000R
|
650
|
580 to 725
|
45
|
37.5 - 45
|
0.023
|
8000
|
|
1700I
|
860
|
725 to 900
|
50
|
37.5 - 45
|
0.028
|
8000
|
|
1700D
|
860
|
845 to 870
|
40
|
47
|
0.024
|
10000
|
Note that for VPH gratings, the efficiency characteristics depend on the grating angle. The uncoated efficiencies of the gratings as a function of grating angle are given below. The grating angle also affects the dispersion, resolution, and wavelength coverage. The wavelength coverage depends also on the camera angle, and the fibre position on the slit. Finally, for any given setup, the resolution (l/dl) varies significantly with wavelength. Phew. The actual wavelength coverage and resolution for any particular setting is given in the Grating setup calculator
Grating setup calculator
is available here
Grating Efficiencies
Preliminary efficiency curves for the AAOmega gratings are available here. All measurements were taken prior to AR coating, so all quoted efficiencies should be increased by a factor 1.08. All curves are approximate, with a 25mm aperture used to test the efficiencies. The different curves for each grating correspond to different grating angles; users can select whatever grating angle is most suitable for their observations. Note that the test may have been done with the grating (and hence slant angle) reversed with respect to the grating calculator. Note that altering the grating angle also has a 2nd order effect on resolution and wavelength coverage; this becomes significant at high dispersion.
Low resolution:
580V
385R
Medium resolution:
1700B
1500V: note angles + 90deg
1000R
1000I
High resolution:
3200B
2500V
2000R
1700I
1700D
More information: Will
Saunders, Rob Sharp
Last modified: 5th September 2005,
Will Saunders
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