SCUBA: Detector arrays |
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As shown below the horns are arranged in a close-packed hexagonal
configuration, covering a field of view of about 2.3 arcminutes, the
maximum practical considering the chop-throw constraints and coma
lobe distortions. There are 37 and 91 bolometers (or `pixels') in
the long- and short-wavelength arrays respectively. The photometric
pixels are arranged around the outside of the long-wavelength array.
Currently, the only available array combination is 450/850
micron. The original design of SCUBA allowed observations at 350,
750, 1100, 1350 and 2000 microns as well, but due to engineering
problems these are not available.
Since SCUBA is situated at the Nasmyth focus, the arrays undergo
rotation with respect to the sky as an obsrvation progresses. Thus
individual observations have to be regridded onto the (RA, Dec)
tangent plane before coaddition.
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