A combination of factors make the summit of Mauna Kea on the Big Island of Hawaii ideal for planetary observing, particularly in the infrared. The altitude means that the amount of water vapour above the telescope is low (water is opaque in the infrared so you can't see through it), plus an inversion layer sits below us that keeps the moist cloud cover well beneath the observatories. The air here is also really stable, limiting the atmospheric turbulence that degrades seeing, which means the stars don't 'twinkle' as much as they do elsewhere. We're also well away from any towns or cities, meaning that the skies are clearer than I've ever seen them. All this means that there are thirteen observatories of different flavours, from the optical to the radio, sat up here on the summit of an extinct volcano.
Infrared Telescope Facility
|Sunset over IRTF on February 4th 2013|
|The telescope and dome before the start of our run.|
Inside the Control Room
The observers and telescope operator tend to work a 12-hour night, coming up at 6pm as the sun sets and then heading back down at 6am, or thereabouts. The telescope operator is in control of the telescope and where its pointing (i.e., what target, and whether we use stars to guide the telescope for added stability on the target), and sits at a large control panel in front of a big window looking into the dome itself (blacked out when we're actually observing). The observers then sit at a series of computer terminals on the other side of the room, controlling the instruments themselves. The instrument can make small corrections of a few arcseconds to move the target around on the arrays (i.e., for subtraction of background emission or bad pixels from the final images), but most of our time is spent setting up the wavelengths of interest, moving filters in and out, deciding how long to integrate for to get clean-looking spectra, and which spectral settings are needed to achieve the desired science.
|Inside the control room, observing Jupiter.|