Photograph by John McDonald
Located 43 km (27 miles) from the summit, Hilo is the largest concentration of artificial light directly visible from Mauna Kea. In this image, the blaze of light and its spectrum can be seen. To the northeast of Hilo, to the left in the photo, smaller communities up the coast are also visible. The spectra of Hilo and nearby communities is dominated by low pressure sodium street lighting. At isolated points outside of Hilo, and many points in town, metal halide, mercury and tungsten spectra are mixed in.
Further northeast from this picture, the shoulder of Mauna Kea obscures lights from the small towns on the Hamakua coast until we reach Honoka'a to the north-northeast of the mountain (another image).
An artefact in the middle left of the image is the spectrum of a bright star off the top edge of the image.