CCD Documentation

CCD Operation - Quick Reference Guide
The following is an abbreviated list of instructions for operation of the Cassegrain Spectrograph with the San Diego State CCD controller and associated software.

An example screen showing the program windows
You will need to run the following three programs in order to perform stellar observations and basic reductions with the cassegrain spectrograph CCD.
These programs are:

CCDTool
ximtool or saoimage or saotng
IRAF (cl) or MIDAS

In your xterm give the commands:
ximtool &
ccdtool &

ximtool opens a display window for ccd images for quick lookup and ccdtool is the main program to run CCD controller

Once you have followed the instructions in the rest of this document you should have a console computer screen that looks similar to the one below (assuming that we are in the process of 'exposing' an image).

CCDTool program

Note that the CCD controller must be powered on before you start the Sun software. See the Using the CCD Controller Document for details on turning on the controller.
Run 'ccdtool';
> ccdtool &

The following main window should appear:

CCDTool Initialization

Click on the SETUP icon.
The following window should appear:

Drag the original CCDTool window out from under the SETUP window.
In the SETUP menu, click on the SELECT ALL button. You should see checkmarks appear in all of the checkboxes.
Click on the APPLY icon. Monitor the log output that will appear in the CCDTool main window as the controller gets set up. There should be no errors for proper set up.

NOTE: You must run SETUP after EVERY TIME you restart CCDTool, and EVERY TIME you have had to press the RESET button on the CCD controller power supply (mounted at primary mirror level).
Note that when communications failures occur between the CCDTool program and the CCD control box, you can sometimes get away without having to go through a full RESET procedure. This is simply done by starting another exposure.

Loading Our FITS Header
Our local FITS header must be loaded manually for the time being. Hopefully in the future we will have it load automatically when 'CCDTool' starts up.
If you click on the FITS menu, you will see that the FITS header information is for the Mt. Laguna Observatory in California as seen below:

To load our local FITS header information, click the Left mouse button on the File icon in the FITS window. This will display the following menu:

Click on the TUG_header file and the click Load.
Now click on the Apply icon in the FITS window.
You should now have the proper TUG fits header information installed.
Alternatively, you can load your private FITS_header, saved previously.

You should now edit the FITS header (ONLY Edit by Hand fields) to set proper keywords.
For each exposure you may, if you wish, set Fits Keywords for the particular exposure, such as EXPOSURE TYPE, OBJECT, DEC, RA, ST, UT, etc.

Don't forget to click on the APPLY button to save these changes.

Exposure Setup

Click on the EXPOSE icon in the CCDTool main window.
The following window should appear:

Modify the image directory and the default FITS file name: Presently we have the following convention:

DIRECTORY: FILENAME: Autoincrement: OFF (not checked)

This will be the normal exposure sequence and will save the exposed image to disk. You have to check display button if you want to see the exposed image on ximtool screen.
Dark frames can be obtained by simply unclicking the "Open Shutter" item.

Full size images (2048x2048 pixel) will occupy about 8 MB on disk. Shortage of disk space in any case is an important fact. So do not store every exposure to disk. First examine the exposed image on the display screen and save it to disk from the exposure window after. To do so uncheck "Save to Disk" option initially on the exposure window before clicking the "EXPOSE" button.
NOTE: Do not clear the FLUSH checkmark in the EXPOSE window. The only control that can be exercised via checkmarks is to have the shutter remain closed by clearing the OPEN SHUTTER checkmark.

Exposure messages

CCDTool gives minimal feedback messages for operations. For example, while an exposure is in progress you will see the following message in the CCDTool window;
reading out CCD

At the end of a successful exposure the following message appears;

exposure complete
After exposure ends, it will take about 90 seconds to read out CCD for full frames. So be patient to see the image on the display screen!!
If any other error messages are displayed (this is unexpected anyway), this may be due to a communication problem with the CCD controller. In such a case you should follow the CCD RESET procedure. It may be necessary to press the RESET button on the controller power supply and to reload the CCD controller programs via the SETUP icon in CCDTool window.

NOTE: The ABORT EXPOSURE icon should be used sparingly , this function is not properly implemented. If you should need to abort an exposure this way it may be necessary to follow the CCD RESET procedure.

Umit Kiziloglu

Last modified: Jan 2000