STIS Spectroscopic Capabilities
To simplify instrument operation and calibration, only specific grating tilts with corresponding central wavelengths are implemented (See the HST Phase II Proposal Instructions).
Spectral format plots for each combination of detector, optical element and central wavelength are available.
Only a portion of the full spectral range falls on the detector for the intermediate-resolution first-order and the echelle (except E140M) gratings. Therefore separate exposures must be taken for these gratings for full wavelength coverage.
Issues to consider when choosing between G230LB and G230L or choosing between G230MB and G230M include relative sensitivity, read noise, plate scale, bright object limits, and detector PSF.
G750L and G750M are subject to long wavelength fringing for wavelengths > 7500 Å.
For more information on First Order Gratings, see the Instrument Handbook:
| Grating/ Prism | Spectral Range (Å) | Dispersion (Å/pix) |
Resolution | Detector | Plate Scale ("/pix) |
||
|---|---|---|---|---|---|---|---|
| Full | Pre Tilt | Spatial | Spectral | ||||
| G140L | 1150-1730 | 610 | 0.6 | 960-1440 | FUV-MAMA | 0.024 | |
| G140M | 1140-1741 | 55 | 0.05 | 11400-17400 | 0.029 | 0.036 | |
| G230L | 1570-3180 | 1610 | 1.58 | 500-1010 | NUV-MAMA | 0.025 | |
| G230M | 1640-3100 | 90 | 0.09 | 9110-17220 | 0.029 | 0.035 | |
| G230LB | 1685-3060 | 1380 | 1.35 | 620-1130 | CCD | 0.051 | |
| G230MB | 1640-3190 | 155 | 0.15 | 5470-10630 | 0.051 | ||
| G430L | 2900-5700 | 2800 | 2.73 | 530-1040 | 0.051 | ||
| G430M | 3020-5610 | 286 | 0.28 | 5390-10020 | 0.051 | ||
| G750L | 5240-10270 | 5030 | 4.92 | 530-1040 | 0.051 | ||
| G750M | 5450-10140 | 570 | 0.56 | 4870-9050 | 0.051 | ||
For more information on the Echelle Gratings, see the Instrument Handbook.
| Grating/ Prism | Spectral Range (Å) | Dispersion (Å/pix) |
Resolution | Detector | Plate Scale ("/pix) |
||
|---|---|---|---|---|---|---|---|
| Full | Pre Tilt | Spatial | Spectral | ||||
| E140M | 1144-1729 | 585 | l/91,700 | 45,800 | FUV-MAMA | ||
| E140H | 1140-1699 | 210 | l/228,000 | 114,000 | 0.029 | 0.047 | |
| E230M | 1605-3110 | 800 | l/60,000 | 30,000 | NUV-MAMA | ||
| E230H | 1620-3150 | 267 | l/228,000 | 114,000 | 0.029 | 0.047 | |
Approximate wavelength solutions for the prism settings at 1200 and 2125 Å are available.
For more information on the Prism, see the Instrument Handbook.
| Grating/ Prism | Spectral Range (Å) | Dispersion (Å/pix) |
Resolution | Detector | Plate Scale ("/pix) |
||
|---|---|---|---|---|---|---|---|
| Full | Pre Tilt | Spatial | Spectral | ||||
| PRISM | 1150-3620 | 2470 | 0.2-72 | 10-2500 | NUV-MAMA | ||