Surveying the Skies by Gareth Wynn-Williams

Author:Gareth Wynn-Williams
Language: eng
Format: epub
Publisher: Springer International Publishing, Cham

VISTA will spend about five years observing the whole southern sky to about the same limit as the UHS, but will spend extra time on selected targets such as the Magellanic Clouds. Its 3-tonne camera, built in the UK, contains 67 million pixels.

6.7 SCUBA-2

As indicated in Figure 6.1, there are atmospheric windows at wavelengths of around 350, 450, and 850 μm that can be exploited from ground-based observatories at high, dry sites. Most of the brightest objects in the sky at these wavelengths are molecular clouds in the Milky Way of the kind discussed in section 5.​7 Within these clouds the dust particles are heated to temperatures of a few tens of degrees Kelvin. These particles radiate most of their energy at wavelengths that can only be observed from space, but many of them also emit enough radiation in the 350-μm to 1-mm range that they can be mapped from the ground.

The most extensive ground-based surveys at these wavelengths are those conducted by the James Clark Maxwell Telescope (JCMT) on Mauna Kea, Hawaii (Figure 6.12). This 15-meter diameter paraboloid antenna started operations in 1987 as a partnership between the United Kingdom, Canada, the Netherlands, and the University of Hawaii. In 2015 it was transferred to the East Asian Observatory, which is mainly funded by Japan, China, Taiwan, and South Korea.

Fig. 6.12The JCMT telescope on Mauna Kea, Hawaii. The telescope is usually protected from the wind by a Gore-Tex membrane which fills the opening of the dome. Image credit: UK Scientific & Technical Facilities Council

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