ESI Modes and Instrument Properties
Modes
ESI has three basic modes:
- Optical imaging
- Low-dispersion spectroscopy (R=1000-6000)
- High-resolution echellette spectroscopy (R=25,000-33,000)
Table 1 provides a summary of these modes, options, and features of ESI.
| Mode | Image or Dispersion | Wavelength, Slit length, Pixel Scale |
|---|---|---|
| Echelle Spectroscopy | high | Wavelength range: 0.39-1.1 microns, R = 25,000-33,000 (depending on order number). Slit length of 20" |
| Low Resolution/Long Slit Spectroscopy | low | Wavelength range 0.39-1.1 microns, R = 1000-6000. Slit length of 480" |
| Optical Imaging | imaging | Wavelength range 0.39-1.1 microns, FOV = 69"x69", 138"x138", 128"x212", 120"x540" (depending on filter size), Pixel scale = 0.1542" |
Instrument Properties
ESI employs a selection of fixed slit widths. Table 2 gives a summary of ESI's properties and design parameters. For more details, see ESI Data Format.
| Property | Echelle Mode | Low Resolution Mode |
|---|---|---|
| Wavelength Range | 0.39 - 1.1 micron | 0.39 - 1.1 micron |
| Pixel scale (along dispersion) | 0.120-0.168"/pix | 0.123-1.70"/pix |
| Resolving Power | 25,000-33,000 | 1000-6000 |
| Slit Widths (arcsec) | 0.30, 0.50, 0.75, 1.00, 1.25, 6.00, 0.3 (pinhole), 0.5 (pinhole), "MultiHole" (line of nine 0.5" pinholes) | 0.30, 0.50, 0.75, 1.00, 1.25, 6.00 |
| Slit Lengths | 20" | 480" |
| Groove Density | 175/mm | (grism not used in this mode) |
| Blaze Angle | 32.3° | (grism not used in this mode) |
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