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Space Telescope Imaging Spectrograph Instrument Handbook for Cycle 22 > Chapter 13: Spectroscopic Reference Material > Echelle Grating E230H

Echelle Grating E230H
Description
The E230H grating is used with the NUV-MAMA and provides echelle spectra at a resolving power of ~114,0001 from 1620 to 3150 .
Special Considerations
A single E230H echellogram covers ~267 , over ~20-70 orders. The orders are spaced by only ~ 12.7 pixels (0.37 arcseconds) at 1650 and 47.2 pixels (~1.38 arcseconds) at 3100 . The grating must be scanned, with exposures taken at six distinct settings to cover the full spectral range of the grating.
 
Dispersion, Cross Dispersion
Plate Scale
λ/228,000
Figure 13.50: Wavelength Ranges for the E230H Grating Settings
E230H Sensitivities
Table 13.14: E230H Throughputs and Sensitivities for a Point Source
Figure 13.51: E230H Point Source (left axis), and Diffuse Source (right axis) Sensitivities. Throughput curve traces the peaks of the blaze function for each order.
Note
Point source sensitivity assumes full transmission (zero slit losses). Diffuse source sensitivity assumes a 0.1” wide slit. To convert point source sensitivities to diffuse source sensitivities multiply the point source values by the grating spatial (cross dispersion) plate scale in units of arcseconds per pixel and by the width of the desired slit in units of arcseconds.
E230H Signal-to-Noise
Note:
The top axis displays constant Fλ values corresponding to the STMAG units (V+STMAGλ) on the bottom axis. Recall that STMAG=0 is equivalent to Fλ = 3.63E-9 erg/cm2/s/. The curves are labeled with exposure times in seconds.
 
Figure 13.52: Diffuse Source Signal-to-Noise as a Function of STMAG for E230H
Figure 13.53: Point Source Signal-to-Noise as a Function of STMAG for E230H
1
R ~ 200,000 possible with the 0.1x0.03 aperture; see page 250.


Space Telescope Imaging Spectrograph Instrument Handbook for Cycle 22 > Chapter 13: Spectroscopic Reference Material > Echelle Grating E230H

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