The Grating Control Window
The grating popup window is the interface to the control and selection
of gratings. In the grating window you can:
Additionally, the current position of the grating is shown in the upper
right of this window in both wavelength and encoder units. The
dispersion is also shown in angstroms/millimeter.
- *Select a Coude Feed grating.
- *Select a camera.
- *Select a collimator.
- *Set the grating order.
- *Set the grating position in encoder units or angstroms.
- *Move the grating repeatedly in small wavelength or encoder steps
- *View the status of the grating system.
Setting the Grating, Camera, and Collimator
The gratings, cameras, and collimators choices are grouped together
under their respective headings in the upper part of the grating
window. Only one choice for each item can be selected at a time. The
current choice is shown with a green background.
To Set a Grating, Camera, or Collimator
- *Click SELECT on the item you wish to use.
- *The item will appear to depress. When TCS acknowledges your command,
the old selection will turn grey and the item you have selected will
Setting the Order and Position
Once the grating, camera, and collimator are set, you can set its order
and position. There are text items in the grating window where the
order and position values are entered. Typically, the order and
position are entered together, but you can also just change the order.
To set only the order
You can enter positions in either encoder units or wavelength units.
- *Click SELECT on the order text input item; it will have a yellow
blinking caret when it is selected.
- *Enter the new order.
- *Make sure there is _no_ value in the Position text item. If there is,
SELECT the Position item and delete any numbers.
- *Click SELECT on "set grating" or type meta-e. You should see a
change in the current grating information at the top of the window.
*To Set the Position and Order
- *Enter an order as in the last section.
- *Click SELECT on lambda or encoder or type meta-l for lambda or meta-d
for encoder. The selected units will be shown in green.
- *Type TAB to select the Position text item (or type meta-p).
- *Enter a position
in the selected units.
- *Click SELECT on "set grating" or type
- *The grating will move and the current position will update to the new
If the grating power is off the system will suggest there may be a
problem. You will also be notified if you ask to go to a position that
is the same as your current position.
The status button shows the current state of the grating system.
Currently, it has no information that is not in the window.