Quick Reference
Plate Scale |
Slit Projection |
Translating the Spectrum |
Guider Field Rotation |
Dispersion |
Wavelength Range |
Resolution and Instrumental Profile |
Optics
| Plate Scale |
|---|
| 3-m | 1.89 arcsec/mm |
| CAT | 9.45 arcsec/mm |
|  |
| Slit Projection |
|---|
| Slit on Detector |
330 μm/pixel (for 15 μm pixels)
264 μm/pixel (for 12 μm pixels) |
| Slit on Sky, 3-m |
530 μm/arcsec |
| Slit on Sky, CAT |
106 μm/arcsec |
|
| Translating the Spectrum |
|---|
 |
Grating Tilt |
1.15 units/pixel (Dewars 6 and 8)
0.92 units/pixel (Dewar 4) |
|---|
| Larger grating settings will move the spectrum
to the right, revealing bluer wavelengths. |
| Dewar Height |
8.97 units/pixel (Dewars 6 and 8)
7.18 units/pixel (Dewar 4) |
|---|
| Larger height settings will move the spectrum
up, revealing bluer orders. |
|
| Dispersion |
|---|
| 5.61 Angstroms/mm @ 10000 Angstroms |
| 3.64 Angstroms/mm @ 6500 Angstroms |
| 1.96 Angstroms/mm @ 3500 Angstroms |
|
|
| Wavelength Range |
|---|
| ~ 3500 to ~ 10000 Angstroms
in 107 orders (m=57 to 163) |
|
| Resolution and Instrumental Profile |
|---|
| Entrance slit |
Resolution | FWHM |
0.2 arcsecs
(3-m scale)
| ~ 100,000
@ 6000 Angstroms
| ~ 1.2 pixels
(0.06 Angstroms)
|
1.2 arcsecss
(3-m scale)
| ~ 60,000
@ 6000 Angstroms
| ~ 2.0 pixels
(0.10 Angstroms)
|
|
|
| Optics |
|---|
| Collimator |
12-inch off-axis parabola, fl=7.4754 m, beam at collimator=0.2084 m |
| Grating |
echelle, 31.5 lines/mm, blaze angle=64.7 degrees, theta=5.5 |
| Cross Disperser |
two UBK prisms at 43.9 degrees |
| Camera |
508.3-mm f.l., f1.7, folded Schmidt camera and field flattener |
| Coatings |
overcoated silver mirrors and anti-reflection coated transmissive optics
|
| Magnification |
-22 (slit to detector, dispersion direction) |
|
| Guider Field Rotation 15 degrees/hour |
|---|
 |
|
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Last modified: Fri Feb 25 13:22:55 PST 2011