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How RoboDIMM is operated

In the interests of completeness, this page provides a step-by-step description of the operating  procedure carried out with RoboDIMM. A brief discussion of the procedure precedes it, along with planned changes.

"RoboDIMM" refers to the monitor equipment, which works completely independently throughout the night. However, the Dome requires user intervention at startup and shutdown of observing, albeit by remote control. The RoboDIMM program is capable of running continuously, starting observations automatically after sunset and stopping at sunrise to wait for the following night. This capability is never used in practice because the Dome must be opened manually before observing can begin.

Given that a Telescope Operator (TO) is present in the WHT all night, it has not been considered not necessary to automate the tasks of opening and closing the dome. Similarly, there are no automatic responses to changes in meteorological conditions: such responses depend on the WHT TO. The advatages of an automatic Dome are improved protection of the equipment from rapid deterioration of the weather and possibly, an earlier start to seeing measurements. However an automatic Dome also carries its own safety risk, for personnel and equipment, and requires careful consideration of fail safe measures. In any case, since there is no rainfall sensing in the ING Met system, automatic closure at present has little advantage.

The current sequence of user operations is as follows:
  1. TO decides whether cloud cover permits observing and humidity is at a safe level

  2. If so, the TO operates a push-button on a panel in the WHT control room to open Dome

  3. TO starts the RoboDIMM programs and uses them to start the monitoring procedure

  4. If no seeing measurements are forthcoming, there are several possible actions:

    1. If slightly cloudy, TO can switch to brighter stars (>  2 mag)
    2. If very cloudy, TO can decide to stop observing and close Dome (no.8)
    3. If it's clear but no star can be found, TO can check telescope pointing
    4. If a star is found but no measurements are being taken, TO can choose to restart the program

      It should be stated that iii and iv above are uncommon events

  5. If interruptions to measurements are caused by high winds, the dome can be partially closed to provide shelter

  6. If the Met system indicates high humidity, the TO must close the RoboDIMM Dome, before closing WHT dome  

  7. At the end of the night, TO can shut down the monitoring procedure or allow the program to stop by itself. This parks the telescope and switches off tracking.

  8. TO closes the Dome, again using the push button panel

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Contact:  (RoboDIMM Project Scientist)
Last modified: 18 December 2010