Picture of a first on Mauna Kea
On the night of May 27th, for the first time, Keck II and Gemini North both propagated their lasers at the same time. Gemini's laser is new and is still being integrated into their AO system...
Subaru and CFHT are also planning to get lasers- when 4 lasers are propagating simultaneously on the summit it will be quite a sight!
Courtesy: Akihiko Miyashita, Subaru Telescope