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September 24, 2023


All about GTC

How will it work?

Technical reliability

The ability to detect and immediately correct problems that could occur while the telescope is working is a guarantee that programmes of observation will be completed and the best scientific results obtained. For this reason, from the earliest phases of the GTC a comprehensive preventive maintenance programme was planned which, together with the use of a queue scheduling system of observations, will guarantee that downtime due to system failure is kept to a minimum.


Observing time is very precious and full use must be made of it. To achieve this, the GTC has a number of special features. One, which sets it apart from other telescopes, is its use of the queued scheduling of observations system. Computers will analyse the atmospheric conditions, the weather, how much observing time there is and what instruments are available. It will use all of these variables to decide which instruments and what type of observation are most suitable for any given moment, so that the telescope can work at its full potential and the scientists can make best use of their time.

Another important consideration is that the secondary is a single mirror. In other words it does not take two different mirrors to work in the optical and infrared ranges, unlike other similar telescopes where the time it takes to swap mirrors means that observing time is lost.

The fact that the primary mirror is segmented makes the aluminium recoating process easier - it is carried out in sections, so that no nights of observation are lost (as happens on telescopes with a monolithic primary mirror).