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
by moving the pointer to the line for the grating order
and typing in the order you want.
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.
- units (encoder or wavelength)
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
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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