Setting the Grating

Often the first task confronting an observer is to set the wavelength of the grating, or to confirm that the grating is set correctly. To open the grating window, move the mouse to the "grating" button at the top of the telescope control window, and click the left mouse button. The grating window will appear. You will then need to select the appropriate by moving the mouse pointer to the proper button and again clicking the left button on the mouse. Set the by moving the pointer to the line for the grating order and typing in the order you want. Select the for the grating tilt, and then enter the encoder or wavelength you want by clicking the left button of the mouse near the input field. Move the pointer to the line for desired wavelength or encoder value, and type in the number you want.

Turn on the grating drive motor in the electronics rack and click the mouse on the "set grating" button to tell the grating to move. After the grating has moved to the correct setting, turn off the power to the grating drive. The grating's position (wavelength and encoder units) is displayed in a box in the upper right corner of the grating window. The reciprocal dispersion, calculated from the camera and grating selected, also appears in the grating position box. The grating window also has buttons for nudging the grating up or down by a specified number of encoder units.

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