The Xpose GUI on the red and blue side is used to start exposures, set binning, and set the number of amplifiers for readout. There are two Xpose GUIs: a red side Xpose located in the center display and a blue side Xpsoe located in the rightmost display. Both Xpose GUIs are displayed on startup. Below you will find descriptions of the actions and information buttons available with the Xpose GUIs. Some buttons display sub windows that accept user input. The subwindows are also described below. Actions or information that are specific to the Red or Blue side are highlighted.
Red side Xpose Widget.
Blue side Xpose Widget.

Setting Exposure Times

To set the exposure time: Notes:
  • The SET button must be clicked to set the desired exposure. Updating the text does not automtically reset the exposure time.
  • You can change the exposure time of the current exposure while it is in progress.
  • Changing the exposure time will update the exposure status bar. Note that the exposure time must be an integer value, with a 1-second minimum (except in dark mode, in which zero seconds is a valid exposure time).
    Action Buttons
    Button Function
    START Star an exposure
    PAUSE Suspend the current exposure. Close the shutter until further action is taken.
    RESUME Continue a previously paused exposure. Open the shutter.
    STOP Immediately stop an exposure and readout the data
    ABORT Immediately close the shutter and discard the current image.
    etc Opens a sub-window to change the CCD readout window and binning
    disk opens a sub-window to access disk write functions
    START DARK Start an exposure without opening the shutter
    CMD ... opens menu from which LRIS scripts are started
    SET sets the exposure time to the number in the box at left

    Exposure Informational Items

    The following items on the Xpose convey additional information about the state of the exposure:
    Erase in Progress
    This message will turn red after the Start button is pressed, to indicate that the detector is being flushed prior to the exposure. When active the text color is red.
    Exposure in Progress
    This message will turn red while the shutter is open and the detector is exposing. When active the text color is red.
    Exposure Paused
    This message will turn red after you have paused an exposure using the Pause key. When active the text color is red.
    Write Crate Memory
    This message will turn red while the detector is reading out. When active the text color is red.
    Warning: Disk write disabled
    This message appears when you have disabled saving of images to disk. Restore writing to disk by using the DISK... subwidget.
    Warning: Image will be dark
    This message appears when you have set the detector in dark mode, meanign that the shutter will be closed during the exposure. Dark mode is turned off once the current dark exposure (or series of exposures) is complete.
    Elapsed Time
    Displays the number of seconds currently remaining on the current exposure.
    Elapsed Time status bar
    A blue bar increases in length during integration to provide a visual update of the exposures status. The target time for the exposure is printed at the right edge of the bar. If the exposure time is updated, the bar status is updated to reflect the change. If the exposure time is updated when an exposure is not currently in progress, the bar updates using the elapsed time from the previous exposure.


    Three additional widgets can be activated from the Xpose widget:

    etc... Subwindow

    The etc... subwidget allows manipulation of the CCD readout window and binning. The blue side may not be windowed, unless the readout is for a single chip. To bin data on the blue side, "Two amp readout" on the left or right must first be selected. If you try to sub_window the blue side or you try binning without setting "Two amp readout," the blue side crate will be lost after the first readout and will require rebooting.

    DISK... Subwidget

    The DISK... subwidget permits changes to the output directory, the output image prefix, and the disk write status:
    Red Side Blue Side

    CMD... Subwidget

    The CMD... subwidget allows the observer to run certain LRIS macros. The macros available under the red and blue sides are not identical.
    Red Side Blue Side

    Quitting Xpose

    One normally does not shut down the Xpose widget by itself; it is generally killed when the Shut Down LRIS Control option is selected from the LRIS Control Menu pulldown menu. It could probably be killed by using the window manager's ``kill window'' function, available by clicking the button at the top left of the Xpose window.