Red Channel Details
Optical Layout
Optical Layout
Aperture Plates and Filters
Aperture Plates and Filters
CCD Parameters
ITL/STA Detector Information
The Red Channel detector has a glow. Please see below for details.
Red Channel Gratings
Grating (lines/mm) | Blaze (order/λ Å) | Blaze Angle(°) | Anamorphic Mag | R (@ Blaze, 1″ slit) | Resolution (Å or Å/order) | Dispersion (Å/pix) | Coveragea (Å) |
Echellette | 11th/5235 | 26.8 | 3270 | 1.6 | 0.58 | 599 | |
150 | 1st/4800 | 2.2 | 0.98 | 230 | 21.0 | 6.37 | 6574b |
270 | 1st/7300 | 5.9 | 0.94 | 640 | 11.4 | 3.59 | 3705b |
300 | 1st/4800 | 4.3 | 0.96 | 460 | 10.3 | 3.21 | 3313b |
600 | 1st/4800 | 8.6 | 0.92 | 960 | 5.0 | 1.63 | 1682 |
600 | 1st/6310 | 11.4 | 0.89 | 1290 | 4.90 | 1.64 | 1692 |
1200 | 1st/5767 | 21.1 | 0.80 | 2620 | 2.20 | 0.82 | 846 |
1200 | 1st/7700 | 28.7 | 0.73 | 3930 | 1.96 | 0.80 | 826 |
1200 | 1st/9000 | 32.7 | 0.67 | 5097 | 1.77 | 0.78 | 805 |
Lo-res Ech. | 7th/5134 | 8.6 | 920 | 5.6 | 1.74 | 1796 | |
Hi-res Ech. | 18th/5790 | 25.7 | 3620 | 1.6 | 0.67 | 691 |
Theorectical Blaze Functions

Red Channel Theoretical Blaze Functions: Red Channel Theoretical Blaze Functions
View a pdf plot of the theoretical blaze functions.
Spectrograph Throughput
An illustration of the expected count rate (for a flat-spectrum (in F_nu) source of 1 micro-Jansky) per Angstrom is shown below.
Red Channel Detector Glow
In Fall 2014, the Red Channel detector developed a “glow” on the blue edge of the detector. This signal is well localized to the corner of the detector, so point source observations and observations focused on the red portion of the detector will likely be minimally effected. Observations of extended sources and programs that utilize the bluest portion of the observed spectrum may be impacted by the signal and its associated noise. A two dimensional image of the bluest portion of the detector is shown below (the spectral direction of the detector runs in the Y-direction, so blue is up in the figure). The image is a bias-corrected dark image. The counts in the “glow” in the upper right depends on exposure time, so observers using long integrations are encouraged to take dark frames. On the right, we show the median counts in this 600s bias-subtracted dark frame in the last 3 columns; again, the bluest portion of the red channel image is at higher Y-pixel values.
