Table of Contents

DSOS User Procedure


  1. Open the dome Shutter. This helps the telescope and the chillers (Neslabs) equilibrate at the ambient temperature.
  2. Tip the telescope to ZA = 45°.
    UIP> za 45
  3. Connect to the VNC desktop.
    mycomp> -l user dsos
    • There are three windows on the desktop
      • The DSOS monitor on the left. The monitor should be running already.
      • The command window on the lower right.
      • The agent window on the upper right.
    • If any of these windows are missing, click on a blank area to display a pop up menu then select the corresponding item to recreate the missing window.
    • Starting the DSOS monitor also starts the DSOS daemon and server, if necessary.
  4. Initialize the system. In the command window, type
    tpick% DSOSinit
    • This creates the baseline setting for the night.
    • Initialization should be done with the dome open, at least 1 hour after sunset, and with the telescope at ZA = 45°.
  5. Enable the power supplies.
    • Display the the power supply page in the status monitor. In the monitor window, type p.
    • Enable the power supply outputs. In the command window, type
      tpick% DSOSpower on
      • The power supplies are normally left in standby mode during the day.
      • On the front panels, the remote light should be illuminated.
      • If any power supplies are in manual mode, start them.
  6. Settling.
    • Depending on the initial toothpick (actuator) displacements, the system needs about 15 min to settle.
    • The power supply monitor page shows the current demands.
    • After settling, the current ideally will be 9 A or less for both +15 V (odd) and -15 V (even) power supplies. Under some circumstances, the current may remain higher.
  7. Display the dish status in the status monitor. In the monitor window, type 1.
    • There is a box for each actuator (toothpick).
    • After settling, all but a few boxes will be white.
  8. System Agent.
    • In the agent window, type
      tpick% DSOSagent
    • Every 2.5 min, the system agent commands the specific actuator (toothpick) displacements appropriate for the telescope ZA.
    • Command values and settings are logged in agent.log.


  1. At the end of observing, stop the DSOS agent. In the agent window, type ctrl-C.
  2. Return the system to its baseline value. In the command window, type
    tpick% DSOSbase
  3. After 10 minutes, disable the power supply outputs. In the command window, type
    tpick% DSOSpower off
  4. Please turn off any power supplies that are in manual mode. Leave everything else on.
  5. Disconnect from the VNC desktop.

System checks

During observations, please check the system periodically.

Should any of these faults occur, turn off the power supplies first. Then shut down the rest of the system. Do not use the DSOS until the fault is repaired. Left uncorrected, these faults may cause system damage and misadjustment of the dish panels.
Essential. Please notify CSO staff what failed and when.



If the system was initialized during the day before sunset, reinitializing 1 hour after the sunset is worthwhile. Another reason for reinitialize is a change of more than 5 °C in the ambient temperature since the original initialization. A significant temperature change in the middle of the night often indicates, however, bad observing weather, so be sure to check for rain or snow. Shutting the dome may be necessary. It is not recommended to rebaseline often.

Power Supplies


On occasion, the power supplies get confused, which prevents them from turning on correctly. If this occurs, reset them.

Do not repeat this procedure more than a couple of times. If it doesn't fix the problem, then something else must be wrong.

Manual start

In unusual circumstances, power supplies may require manual starts. Power supplies are always operated in pairs.

New style
  1. Turn on both supplies using the switches on the left of their front panels.
  2. Once the supplies stabilize, the panel displays will indicate (close to) zero voltage and current.
    Output 0.00 VOLTS
            0.0 AMPS
  3. Press the MENU buttons near the keypad on the right of the front panels.
  4. The displays will indicate the memory locations, 1 ≤ N ≤ 9, and the the correct correct voltage and current settings.
    Restore from Memory: N
     15.00 V 75.0 A 3000 W
  5. After the proper settings are displayed on both supplies, simultaneously press the ENTER buttons on the right of the panels. This applies both biases to the power amps at the same time.
  6. The displays will initially indicate something like:
    Output 15.00 VOLTS
            75.0 AMPS
  7. Repeat for any other pairs of supplies in manual mode.
Old style
  1. Turn on both supplies using the switches on the left of their front panels.
  2. Press ENABLE on the left side.
    • Simultaneously with the new style ENTER if a mixed configuration is used.
Turn off
  1. Turn off supplies using the switches on the left of their front panels.


Chillers (Neslabs)

If any of the chillers sounds an alarm, check its error display.


If any of the four pumps supplying the dish manifolds fails, usually the meters will read low (or no) pressure and the pump may be hot to the touch.