External power

Lightning caused an external power failure of the electrical supply. It was necessary for the electricity company (Endesa) to get a special vehicle to the island to help identify the location of the problem, followed by the repair itself. As the weather was also bad, this took a rather long time.

When we do not have external power, the telescope can not be operated as we need the cooling to keep the electronics at working temperature, and the emergency electricity system (UPS) we have does not have sufficient capacity to keep the telescope running. When there is a power cut, we still have some time to stop and close the telescope as the electronics do not warm up that fast.

To avoid this problem, we have been working on a passive cooling system. As long as the outside temperature is low, which is likely the case in any night, we will be able to run the telescope always, even if there is no external power. For this to work, an electronic control unit was built, but due to the sickness of our technician this was not installed yet.

When there is a power cut, the UPS immediately supplies power. This comes first from its batteries, and the emergency generator is started as soon as possible. The batteries have only a limit capacity, and when the generator does not work, we can operate only for a short while. A system has been developed where the Telescope Control System (TCS) knows what is the remaining time the system can still be operated using the current capacity of the batteries. If there is no external power, and the battery capacity gets to the lowest level where we are still sure the telescope can be stopped and fully closed, the telescope will close down automatically.

During the extended period of the power cut, a temporary installation was made to use the passive cooling system by the local company that developed the electronic control unit for it. With the passive radiator cooling it was possible to get the water temperature down to approximately 17 C with an ambient temperature averaging around 12 C, showing that the system functions. In the limited time we might have operated the telescope when this was working, it was considered too dangerous to be used when regular observers are alone at the telescope, as there was no safety system in place to make sure this was working properly at all times.

When the electricity cable was finally repaired, observations were started within 1/2 hour.