A Spanish judge in a decision cheered by environmentalists has put a halt to backup plans for the construction of a giant telescope in the Canary Islands — eliminating at least for now the primary alternative location to the preferred spot in Hawaii, where there have been protests against the telescope. Construction of the Thirty Meter Telescope, or TMT, on Hawaii’s tallest mountain, Mauna Kea, has been stalled by opponents who say the project will desecrate land held sacred to some Native Hawaiians.Telescope officials had selected the alternate location near an existing scientific research facility on the highest mountain of La Palma, one of the Spanish islands off the western African coast, in the Atlantic Ocean. But an administrative court in Santa Cruz de Tenerife, the capital of the Spanish archipelago, ruled last month that the 2017 concession by local authorities of public land for the tentative project was invalid. The ruling was dated on July 29, but …