A beautiful timelapse of the observatories atop Mauna Kea, Hawaii. The summit is at an altitude of nearly 14,000 ft and is the premiere site for astronomy in the Northern Hemisphere. Watch the video…
Images screen capture from video
“As an astronomy graduate student at the University of Hawaii, I’ve enjoyed excellent access to the facility. Some of my favorite still images of Mauna Kea can be found at sgphotos.com.
This montage was filmed on three nights in April (I was observing on one of the telescopes and would walk outside when things got boring) and four nights during summer 2013.”
Laser guide stars are an artificial star image created for use in astronomical adaptive optics imaging.
Adaptive optics (AO) systems require a wavefront reference source in order to correct atmospheric distortion of light (called astronomical seeing). Sufficiently bright stars are not available in all parts of the sky, which greatly limits the usefulness of natural guide star adaptive optics. Instead, one can create an artificial guide star by shining a laser into the atmosphere. This star can be positioned anywhere the telescope desires to point, opening up much greater amounts of the sky to adaptive optics. Because the laser beam is deflected by astronomical seeing on the way up, the returning laser light does not randomly move around in the sky as astronomical sources do. In order to keep astronomical images steady, a natural star nearby in the sky must be monitored in order that the motion of the laser guide star can be subtracted using a tip–tilt mirror. However, this star can be much fainter than is required for natural guide star adaptive optics, because it is only used to measure tip and tilt and all higher order distortions are measured with the laser guide star. This means that many more stars are suitable and a correspondingly larger fraction of the sky is accessible.