Just one or two more photos from the summit at sunrise on a Saturday morning. Above, the mountain in the background is the volcano Hualalai. It's considered a potentially dangerous volcano by the USGS because even though it hasn't erupted for a few hundred years it'll likely erupt again and there are several towns nearby. Unlike most of the other Hawaiian volcanoes, it has an occasional tendency to erupt violently in a similar manner to infamous volcanoes like Mt St Helens although on a somewhat smaller scale. John, over at "Kona - a pedestrian view", often hikes the slopes of this volcano.
The slope to the right is Pu`u Poli`ahu, a cinder cone near Mauna Kea's summit. It almost looked as though it had an eruption of light which was flowing down its eastern flank!
My favourite telescope - the United Kingdom Infrared Telescope (UKIRT). The strange looking "windows" on the side of the dome are part of the dome ventilation system (DVS). During normal operations these are opened early in the evening to allow the outside air to blow through the dome and help equalise the inside and outside air temperatures. This reduces local turbulence, especially in the first few hours of the night and has been a great success in improving delivered image quality. For me, it's strange seeing the DVS closed as I tend to be around in the evening when it's nearly always open!
Subaru to the left and the twin Kecks plus the morning shadow of Mauna Kea. Although things will change in the next few years, you don't tend to see ground-based optical-infrared telescopes bigger than these!