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.
Accordion
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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 Per 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 Per 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 Per Tilt Spatial Spectral PRISM 1150-3620 2470 0.2-72 10-2500 NUV-MAMA
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Please contact the HST Help Desk with any questions.