Figure 1: A comparison between the detector quantum efficiency of the Goodman (blue) and the RC (magenta) spectrographs.
| RC
Spectrograph |
Goodman
Spectrograph |
Notes |
||
| Telescope |
Blanco 4.0m |
SOAR 4.1m |
||
| Resolving
Power @550 nm |
730-5700 |
1390-2800 |
A |
|
| Resolving
Power @550 nm with a 1 arcsec slit |
730-5700 |
615-1320 |
||
| Optimal
Wavelegth Range |
320-1000 nm |
320-850 nm |
B |
|
| Slit |
||||
| Slit length |
5.5 arcmin |
5 arcmin |
||
| Matching
slit width |
1.0 arcsec |
0.45 arcsec |
A |
|
| Available
slit widths |
Continuously variable |
0.45, 0.84, 1.03, 1.35, 1.68
arcsec |
||
| Multiplexing? |
no |
no in 2008B |
||
| Spatial
Scale |
0.5 arcsec/pixel |
0.15 arcsec/pixel |
||
| |
||||
| Peak
Overall System Efficiency |
10-18% |
20-30% |
C |
|
| Detector |
Loral 3k |
Fairchild 486 |
||
| Useful
Format |
3072 x 800 |
4142 x 1896 |
||
| RON (e- RMS) |
7.3 | 7.7 | 11.0 |
3.3 | 3.7 | 8.6 |
D |
|
| Read Out
Time (seconds) |
184 | 120 | 88 |
157 | 79 | 20 |
||
| QE |
See Graph |
|||
| Fringing |
> 700nm, peak amplitude ~1%
at 850nm |
> 670nm, peak amplitude
21%@900nm |
||
| Notes: |
||||
| A) The slit width which projects to
2 pixels on the detector for the RC Spec and 3 pixels for Goodman. The stated maximum resolving power is using a slit of this width. |
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| B) For the Goodman this is the
wavelength range over which the optical design and coatings were
optimized. Use at redder wavelengths out to the sensitivity limit of the detector is possible with some degradation in image quality. |
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| C) Values at the peak of the grating
blaze measured using spectrophotometric standards with a wide (> 10
arcsec slit). Goodman values are preliminary and will be updated as further data become available. |
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| D) Size of the region of interest on
the CCD required to cover the full slit length in spectroscopic
mode. The read out times given are for this ROI with 1x1 binning.
For both detectors, it is possible to select ROI size, location, and
binning. |
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This page was last updated on 02 March 2008 by
SDP.
Please send comments or questions to
spoints@ctio.noao.edu.