Grating Tilt and Dewar Height
The Grating Tilt and Dewar Height stages are used to position the spectrum on the detector. Both these stages are controlled from the spectrograph motor control interface hammotor_gui (see Figure 1 for the GUI interface). Both stages use motor steps as the units. The scale factors for moving the spectrum on the detector are as follows:| Grating Tilt | 1.15 steps/pixel (Dewars 6 and 8) 0.92 steps/pixel (Dewar 4) |
|---|---|
| Positive grating tilt settings will move the spectrum to the right, revealing bluer wavelength. | |
| Dewar Height | 8.97 steps/pixel (Dewars 6 and 8) 7.18 steps/pixel (Dewar 4) |
| Positive dewar height settings will move the spectrum up, revealing bluer orders. | |
See Navigating the Spectrum for more information on identifying wavelengths and positioning the spectrum on the detector.
Figure 1: Grating Tilt and Dewar Height
Figure 2: Translating the spectrum on the detector.
Support Astronomers (sa@ucolick.org) Last modified: Tue Feb 15 14:14:15 PST 2011