ULTRACAM user manual

Version: 22 May 2003

1. Introduction
2. Powering up
3. Powering down
4. Afternoon activities
5. Taking data
6. Looking at data
7. Archiving data
8. Changing CCD parameters
9. Setting up on an object
10. Drift mode
11. Calibration frames
12. AutoLogger
13. Changing filters
14. Before you go to bed
15. Troubleshooting
16. Contacts

• ULTRACAM system maintenance document. This document describes ULTRACAM's camera head handling and system maintenance procedures. It should only be of relevance to project personnel.
• CCD application document. This document describes the various CCD controller applications that can be run with ULTRACAM. You should regard the applications document as the primary source of reference for the different readout modes and their associated parameters, although a summary of its contents is given below.
• ULTRACAM pipeline software manual. This document describes how to use Tom Marsh's pipeline data reduction software, which is the best way of viewing the data whilst observing.
• Telescope operators guide. This document describes how to use ULTRACAM with the WHT Telescope Control System and is intended primarily for telescope operators at the ING..

1. Turn off the SDSU controller (refer to the Powering up section for the location of all relevant power switches).
2. Turn off the water chiller. This will cut the water flow and hence will automatically turn the peltiers off (but check the peltier displays to make sure). With all cooling turned off, the chips will gradually warm up to ambient temperature at a safe rate.
3. Turn off the peltier devices.
4. Shut down the rack PC by typing "init 0" in an xterminal connected to the PC and then wait for a couple of minutes. This does not turn the PC power off, so when the system is halted it will then be necessary to press the "Power" button on the front-panel of the rack PC.
5. Turn off power to the rack unit.
6. Shut down the data reduction PC by pressing the ctrl-alt-del buttons at the login prompt. The PC will power down automatically on completion.

1. Check water temperature on the chiller display is set to 10 degrees, unless this is within 10 degrees of the dew point (in which case the water temperature should be increased). The dew point can be determined from the observatory meteorological system. A useful check on this is to run your hand along the base of the SDSU controller. If it feels even slightly clammy to the touch, increase the water temperature slightly.
2. Check CCD temperatures on the rack-mounted temperature controllers are stable at -40 degrees.
3. Check peltier power usage on the rack-mounted temperature controllers. These should typically be around -30%. If the value is close to or equal to the maximum value of -55% then there is either a problem with the vacuum in the head or the CCD temperatures have been set too low (or the water temperature too high).
4. Check for water leaks by running your fingers along the pipe connectors on the water chiller, the SDSU controller and the individual CCD heads.
5. Check the nitrogen gas flushing system is operable by ensuring that all the blue pipework and syringe needles on ULTRACAM are connected, that the small brass valves on ULTRACAM are fully open, and that the gauge feeding ULTRACAM is set to a flow rate of appoximately 1 litre/minute.
6. Ensure that the water pipes and GPS cable leading up to the instrument are neatly arranged beneath it and are in no danger of snagging on any equipment.
7. Ensure that the star-field tube is not mounted on the ULTRACAM collimator, that the focal-plane mask is fully retracted and its foam baffle is in position.
8. Check which filters are installed in front of each CCD, either directly by taking the cartridges out or indirectly by looking in the filter case to see which filters aren't mounted (see Changing filters).
9. Start the observing system (see Taking data), take some bias frames and check the readout noise and bias level (see Calibration frames and Looking at data).
10. Ensure the safety of data taken the previous night by moving it to a subdirectory on the rack PC, copying it to the data reduction PC and archiving it to DVD or DDS4 (see Archiving data).
11. If you want the first run of the coming night to be run001 (recommended), make sure all runs in  /data on the rack PC have been moved/deleted and then restart the observing system (by hitting ctrl-c in the camera and filesave windows and typing simple_startup -full name again - see Taking data).

1. Log into the ultracam data reduction PC (known as ultracam). If you don't have a user account on this system, please contact Paul Kerry.
2. Log into the rack PC (known as ucam2) as root. It is only possible to do this via ultracam using ssh. To ease this process, you can type rack, which will automatically log you into ucam2 as root without having to type a password. If you are asked for a password, then a setting is amiss - please contact Paul Kerry. Because you are logged in as root you need to be extra-cautious with your typing.
3. In an xterminal on ucam2, type:

   ucam_startup

   and follow the prompts. This script sets the system clock, which is often very inaccurate, leading to confusion with data file-creation times. The script also resets the system logging files, which become full with ULTRACAM debugging messages, causing the rack PC to run extremely slowly. Once run, you shouldn't need to run this script again until the next night (or the next time the rack PC is rebooted).
4. Ensuring that the SDSU is switched on, type the following in an xterminal on ucam2:

   simple_startup -full name

   where "name" can be any string you choose (and does not have to be surrounded in quotation marks if there are no spaces in it). The "-full" option tells the system that you don't intend to use drift mode. If you wish to use drift mode, you need to use the "-fast" option (see the Drift mode section below). The following windows should then appear:

   

   The "Camera" window (top-left) provides information on the commands used to control the CCD cameras, which are sent to the SDSU controller. The "Filesave" window (top-right) provides information on the commands used to define the quantity of data to be expected, and are sent to the SDSU-PCI card in the rack PC. The "Netscape" window (or "WebGUI") sends the xml documents containing the camera and filesave parameters to the SDSU controller and PCI card via the http protocol.

5. Set the file headers by clicking on the following links in the "engineering" column of the netscape window:
   • setup wht (camera)
   • setup wht (filesave)
   • setup ultracam (camera)
   • setup ultracam (filesave)
   These links must be clicked in order from top to bottom and each time you click on a link in the web browser you must wait for the netscape "busy" graphic to stop before clicking on the next link. If each operation is successful you will get a message in the status window at the bottom left of the web browser which contains the word "ok". You will also obtain a line in the history window at the bottom right of the web browser showing you which links have already been activated.
6. Power up the SDSU controller by clicking on the following links in the netscape window:
   • poweron (camera)
   • poweron (filesave)
   • GO
   You should now see a full set of LED's illuminated on the SDSU controller. Because of a bug in the current ULTRACAM software, it is now necessary to do the following to complete the SDSU power-on sequence:
   • Press ctrl-c in the camera window.
   • Press ctrl-c in the filesave window.
   It is essential that you do this in the order given above. There is no need to close the netscape window as it will respawn itself automatically.
7. Now restart the software using the command:

   simple_startup -full name2

   where "name2" can be any string as long as it is different to the string you used the first time. The camera and filesave windows will now reappear and, after a few seconds, the netscape window will be respawned - make sure you wait for this to happen before clicking on any links.

8. Set the file headers again by clicking on the following links in the "engineering" column of the netscape window, in the following order:
   • setup wht (camera)
   • setup wht (filesave)
   • setup ultracam (camera)
   • setup ultracam (filesave)
   There is no need to click on the "poweron" links again, as the SDSU controller has already been powered on.
9. You are now ready to take data. You can select either one of the "generic" modes or one of the "user-defined" modes - the difference between these two options is described in the section on Changing CCD parameters. If, for example, you decide you want to take data in 2-windowed mode using the CCD parameters given in the generic xml file, you should click on the following links:
   • 2 windows (camera)
   • 2 windows (filesave)
   • GO
   • STOP
   It is always necessary to download first the camera application and then the filesave application. You must wait for each application to successfully download before clicking on the next link. In the above example, the NO_EXPOSURES parameter is set to -1 in the xml file (see Changing CCD parameters), and hence data will be taken indefinitely until you click on the "STOP" link. When this occurs, you will obtain a message in the filesave window telling you how many exposures were taken and a message in the status window saying "ok".
10. Once you have started a run, type the following command in an xterminal logged into the rack PC:

    ucam_data_limit

    Hit return in response to all the prompts (unless you want to check the speaker volume or change the file size limit). This script checks the latest run and outputs an audible warning when it becomes dangerously close to the maximum file size limit of approximately 2 GBytes. When you hear the alarm, you must stop the current exposure. If the file size goes over the limit, the rack PC will crash.
11. When you are ready to take your next exposure, you must reload the camera and filesave applications for your chosen CCD setup and then click "GO", even if you have not changed any of the parameters.

source /home/trm/.cshrc
ultracam

source /usr/local/ultracam/trm-ultracam-1.0/Ultracam

FileServer

Please refer to Paul Kerry's guide to archiving ULTRACAM data.

cd /ultracam/config/xml

• NO_EXPOSURES - the number of exposures. It is usual to set this to "-1", which means that exposures are obtained until the "STOP" link is clicked on the netscape window.
• GAIN_SPEED - the gain and readout speed. It is usual to set this to "0xcdd", which is a gain of 1.2 electrons/ADU and a slow readout speed (10 microseconds/pixel/second/channel). Setting to "0xfdd" gives a faster readout speed at the expense of significant pickup noise on the chip.
• EXPOSE_TIME - this is the exposure delay time (in units of milliseconds) which should be added to the irreducible minimum exposure time due to the time it takes to read the chip out to give the total exposure time. Do not enter a value of 0 (or less), as it will crash the system.
• X_BIN_FAC - the x-binning factor, which must be an integer multiple of the x-size.
• Y_BIN_FAC - the y-binning factor, which must be an integer multiple of the y-size.
• V_FT_CLK - the vclock speed. It is usual to set this to "0x990000", which gives a vertical clocking speed of 24 microseconds/row. If you lower this, you run the risk of lowering the count-level at which the "peppering effect" occurs (see the Troubleshooting section for details).
• X1L_START - the x-start position of the first window on the left-hand side of the chip.
• X1R_START - the x-start position of the first window on the right-hand side of the chip.
• Y1_START - the y-start position of the first pair of windows.
• X1_SIZE - the x-size of the first pair of windows.
• Y1_SIZE - the y-size of the first pair of windows.
• X2... ditto for the second pair of windows.
• X3... ditto for the third pair of windows.

set_objectname.xml

cd /ultracam/src/ucam/WebGUI/vik
emacs control.html

<li> <a href="javascript:cam('set_objectname.xml')">
objectname (camera)</a> </li>
<li> <a href="javascript:fs('set_objectname.xml')">
objectname (filesave)</a> </li>

Change the "objectname" string to whatever you have decided to call your xml file, save the file, and then press the "reload" button on the netscape window. Your new setup should now appear as an option under the "user-defined modes" column. Be careful in this directory, as it is the main repository for the html files used for the WebGUI (i.e. the netscape window on which you run the observing system). If you do delete anything by accident, there is a copy of the directory on ucam2 in /root/pkerry/webgui_backups_21_5_03.

Target acquisition

The WHT points to better than a few arcseconds and the centres of the ULTRACAM chips are within a few arcseconds of the rotator centre (to which the WHT points). Hence, as long as your coordinates are accurate to a few arcseconds, you can be certain that when you slew to your target it will appear at the very centre of the ULTRACAM chips, making target identification very easy.

The scale of the ULTRACAM chips on the WHT is 5 arcminutes (0.3 arcseconds/pixel), but the orientation is variable, as it depends on the orientation of ULTRACAM, its mounting collar and the A&G box with respect to the WHT, all of which are subject to change from one observing run to the next.

The best way of positioning targets on the ULTRACAM detectors is to use the "setup" application under the "generic modes" column on the netscape window. This is just a two-windowed setup in which the windows are the same size as the whole chip and the pixels are binned by a factor of 4. With a 1 millisecond exposure delay, this results in an exposure time of approximately 0.25 seconds, with negligible dead-time. The rapid readout and large field of view results in an acquisition-TV-type mode, which greatly facilitates target acquisition.

Setting CCD windows

Exposure times

The "Gauss" option in "rtplot" can be used to determine the maximum counts in an aperture centred on the star. Do not mistake this with the "peak height" value - the maximum value of the Gaussian fit to the stellar profile - which may underestimate the true maximum. If the exposure time needs to be lengthened, increase the "EXPOSE_TIME" parameter in the appropriate xml document (see Changing CCD parameters). If the exposure time needs to be decreased, and the EXPOSE_TIME parameter is already at its minimum value of "1", you will need to either decrease the size and/or number of windows being read out, bin the pixels, change the "GAIN_SPEED" parameter or adjust the window positions to minimise the "DIFF_SHIFT" (see the CCD application document).

simple_startup -fast name2

The "-fast" option must only be used when running drift mode applications - the system will not work if you attempt to run any of the other observing modes. Likewise the system will not work if you attempt to run drift mode applications having brought the system up using the "-full" option.

It should be noted that with the current version of the ULTRACAM software it can take over a minute to download drift mode applications, i.e. the netscape window will be busy for over a minute before responding with an "ok" in the status window. On no account should any other links be activated before the browser has successfully downloaded the appplication.

Standard stars

These are best selected from the list of Smith et al. 2002 (AJ, 123, 2121).

To run the AutoLogger for data on the rack PC whilst observing on 20/05/2003, type the following:

cd /ultracam/src/ucam/WebGUI/vik/AutoLogger
emacs 20_05_03_log.dat    -    and enter the object name, filters and comments for each run
AutoLogger    -    ignore the various error windows which will pop up
  >   /data
  >   20_05_03_log

The script will run indefinitely, polling the data directory a few times every minute and looking for changes in either the data files or the comments file. If it finds a change, it will update the log displayed on the web browser. To exit AutoLogger, just type crtl-c, but only do this when AutoLogger says that it is safe to. The final log is written to a file in html format - in the example above the resulting file would be called 20_05_03_log.html. To print out the html log file, it is best to run the konqueror web browser on the data reduction PC, load the html log, and then print to a postscript file, setting the page size to A4 and the orientation to landscape.

AutoLogger can also be run off-line, either on the rack PC in exactly the same way as described above, except that any directory containing ULTRACAM data can be polled, or on the data reduction PC. In the latter case, AutoLogger resides in /home/vsd/AutoLogger and it can be used to poll any directory on the data reduction PC which contains ULTRACAM data.

As well as the automatic log, we also keep a hand-written log which details weather conditions, run numbers, filters and any comments. It is essential that this log is carefully kept as it provides a backup to the electronic version. Before you start observing on each night, print out one copy of this title page template and then multiple copies of these blank tables.

1. Make sure that the hand-written and automatic logs are up-to-date and complete for the night.
2. Shut down the observing system by typing ctrl-c in the camera and filesave windows and closing the netscape window (see Taking data).
3. Close down all windows which are logged onto the rack PC.
4. Turn off the SDSU controller (see Powering up).
5. Copy all data obtained during the night from the rack PC to the data reduction PC (see Archiving data).
6. Go to bed.

Please consult Paul Kerry's networking document.