The European Southern Observatory (ESO) Council will soon decide where to install the European Extremely Large Telescope (E-ELT). The currently recommended site is Armazones, a sierra near Paranal in Chile (Nature 464, 146; 2010). But there is also a strong case for considering the Roque de los Muchachos Observatory (ORM) on the Canary Island of La Palma.

This European site has the support of the European parliament and meets the astronomical requirements and logistical services necessary to make the operation cost-effective. For example, the E-ELT will need to use adaptive optics, which require a high-quality atmosphere in which the turbulent layers are as near to the telescope entrance as possible: the ORM's stable and predictable atmosphere makes it the best-quality site under consideration, as well as the most well studied.

Spain has offered the €300 million (US$400 million) needed to implement the project. Siting the telescope in this European ultra-peripheral region would make it eligible for additional funding for its construction and operation.

At the meeting of the European Conference on Research Infrastructures held last month in Barcelona, it was stressed that all European research-infrastructure projects must minimize and optimize their construction and operational costs. These stipulations could be fulfilled by choosing the ORM option.

Another factor is the high seismicity of the Armazones region, which could affect the E-ELT's huge structure, multiple mirrors, complex instrumentation and adaptive optics. Additional security provisions could double the estimated costs.

European astronomy should not put all its eggs into one shaky basket, when there is an alternative secure site nearer home that offers equally good astronomical conditions.