Canada-France-Hawaii Telescope

A User's Manual For the CCD Data Acquisition User Interface

The User Interface environment

The Command menubar

This figure shows the general layout of a session. Across the top of the screen is the command menubar. It includes a row of control buttons, a help pull down menu, a session configuration pull down menu, and a text window displaying one-line help messages. The menubar contains all of the necessary controls for your observing session.

Selecting one of the buttons, by clicking one with the left mouse button, will cause a process to be invoked: a new window called a form will open and be made available to the user for further interaction. Some forms take more time to open up, so be patient.

Feedback window

Down in the lower-right portion of the session screen, we see the feedback window. Note that the instrument name is part of the title area. The feedback window exhibits information pertinent to the form being implemented. The start-up of a form usually outputs a line or two to the feedback window and errors are listed there as well. The lines in this window can be scrolled, so that previously displayed output can be re-examined. It is therefore wise to consult the feedback window often to monitor the progress of the session and requested operations.


Icons are used to inform the user from running processes. Two types of icons exist:

Clock, Disc meter, Load meter

To the left of the feedback window are miscellaneous tools provided for the user's convenience. On the session screen, we see a clock and a CPU load meter which gives feedback of the system's present performance. The CPU load meter can be helpful to diagnose a system malfunction: if a process goes wrong somewhere, the CPU load will increase to non-standard levels (several horizontal bars and upward trend).

The third meter is showing the percentage of disk space remaining. The background color of the meter may turn orange; aiding to convey the message that it is time to save some files to tape and delete them from the disk. The current observing environment provides a 4 gigabyte disk for storing images. This corresponds to approximately 500 full 2048x2048 images. With the current system, it would require approximately 25 hours to generate 500 full frame biases.

Console window

This window is usually iconified in the lower left corner of the session screen. This is a simple HPterm window from which UNIX commands can be entered. It is generally of no use to the user/observer.

Image and forms location

A large fraction of the session window is devoid of any windows and is referred to as the root window. This is where the forms will appear after clicking in the desired menubar option. It is possible to open several forms at the same time. However, each form being a separate process, the computer load is increased proportionally.

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