>Thirty Meter astronomers had said if they didn’t get a green light to build on Mauna Kea, they would build it on La Palma in the Canary Islands, off Africa.
Altitude is not everything, and higher altitude does not automatically translate into better performance of the instrument. There are many, many factors that matter, including light pollution, transparency, cloud cover, air turbulence, jet streams, etc.
A report by the Canadian Astronomical Society (Canada has a ~15% stake) found that with taking all these variables into play, Mauna Kea is still the best site for TMT. See page 35 for the final recomendations: http://casca.ca/wp-content/uploads/2017/03/CATAC-Report-Fina...
Of course. I was not saying Mauna Kea is not a good location. I was just saying there is a whole bunch of factors that matter besides altitude.
La Palma's air quality is also not as good as Mauna Kea's (more dust blowing over from the Sahara), if I recall correctly. It may be the second best site in the northern hemisphere, but it's significantly behind the top choice.
I had the impression this was more of a negotiating tactic than an actual plan. But this is like fourth-hand rumor.