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Stars and the Milky Way Embrace the Telescopes on Maunakea

December 14, 2015
Last updated: January 19, 2021

Images of the night sky taken from the summit of Maunakea by an astronomy graduate student have been combined into a set of fascinating time-lapse sequences showing the unearthly beauty of the summer stars and the mountain on a special night called "Tanabata." Sean Goebel, a member of the Institute for Astronomy at the University of Hawaii and part of the adaptive optics team at Subaru Telescope, wanted to show how the sky and earth meet in a sequence that also showed the passage of time and our place in the cosmos. "When looking up at the sky, wherever the location on this planet is," he said, "one can feel that the elements that make us and the planets all come from somewhere in the universe."

The night of Tanabata, also called "Night of the Seventh", is a time on the traditional lunar-solar calendar in Japan that commemorates the seventh night of the seventh month. It is often celebrated as the "Star Festival" during July and August. This "Tanabata time" commemorates a night when a mythical couple represented by the stars Vega and Altair, which are separated by the Milky Way, can meet once a year. In the image sequences, those stars also watch over the telescopes as they work throughout the night.

Sean's first sequence of images aims at the sky from the summit ridge on Maunakea, with the Subaru Telescope in the distance. Four telescope buildings appear in the clip, from left to right: the Subaru Telescope, the twin Keck Observatory telescopes, and NASA's InfraRed Telescope Facility. The enclosure of the Subaru Telescope, which co-rotates with the telescope, shows short, quick rotations. The Keck Observatory telescopes are seen deploying laser guide stars, which allow astronomers to conduct observations using adaptive optics to reduce the effects of atmospheric turbulence. Far to the right and off the mountain are flames from brush fires near Kawaihae Port in the northwest side of the Big Island of Hawaii. The bright, 25 % full moon rises after midnight and lights up the scenery almost as if it were sunrise.

The second segment was taken from the area called "Submillimeter Valley," where the radio telescopes sit. The summit ridge has optical and infrared telescopes, while this lower and wider area has three different facilities for observing the radio waves from objects in the universe at the submillimeter range. From this valley viewpoint, the northern sky and circumpolar stars are visible over the Subaru Telescope. The 15-meter aperture James Clark Maxwell Telescope has a membrane in front of the telescope that protects the telescope from wind and other weather conditions. The 10-meter aperture Caltech Submillimeter Observatory telescope is half-exposed, showing a variety of LEDs from its auxiliary systems. The SubMillimeter Array, a group of several antennas that have the viewing area of one big radio telescope, was visible in the first sequence.

The third segment was taken between the Subaru Telescope and neighboring Keck I telescope. The Milky Way comes into view over the Subaru Telescope later in the sequence. Mauna Loa, another tall mountain in the Island of Hawaii is visible to the left. The light from the observatory on its slopes is for the study of the atmosphere. The time-lapse covers several hours in a just a few minutes, which gives the impression that observatory vehicles ascend the mountain as if they are flying up the road instead of the safe speeds they really observe.

At one point, the enclosure of the Subaru Telescope turns west, just as the wind becomes stronger. The night's observations required the Hyper Suprime Cam, which is installed at the top of the telescope. To protect this very unique instrument and the telescope itself, the wind screen was deployed.

Video: Summer Nightscape of Maunakea (Credit: Sean Goebel/NAOJ) This video contains three time-lapse segments of images of the skies over Maunakea. The first segment captures the Subaru Telescope from a distance, from the summit ridge of Maunakea, shot with a Canon EOS Rebel T2i (Kiss X4 in Japan or EOS 550D in other regions). The second segment, looking up from the lower valley and shot with a Canon EOS 5D Mark II camera, shows radio telescopes in addition to the optical-infrared telescopes. The third segment is a close-up of the Subaru Telescope enclosure. Camera (Canon EOS 6D) was located between the Subaru Telescope and Keck I telescope. All movies are composed of a series of images each at 30-second exposure taken by Sean Goebel (Institute for Astronomy, University of Hawaii and the Subaru Telescope, NAOJ).

The stars and observatories aren't the only things seen in the time-lapses. Many objects cross the sky: airplanes, satellites, and shooting stars. Some of the planes might be carrying the mail, since mail delivery for all the islands goes through the main office in Honolulu. Satellites carry messages, too: telecommunications, entertainment, and other data important to our technological cultures.

The shooting stars are really meteorites, not stars. They are remnants of the primordial solar system and carry information about conditions as the Sun and planets formed some 4.5 billion years ago. In that sense, they are also postal carriers with very important information about solar system history. Some meteors supply elements such as sodium to Earth's atmosphere. The laser guide star systems utilize the sodium ion layer at 90-km (56-miles) high to create artificial stars for telescopes focus on as part of their adaptive optics. The tiny fireballs seen in the sequence are probably precursors to the Perseid meteor shower, which had its maximum display a few nights later.

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