First results from the Very Small Array -- I. Observational methods
  The Very Small Array (VSA) is a synthesis telescope designed to image faint structures in the cosmic microwave background on degree and sub-degree angular scales. The VSA has key differences from other CMB interferometers with the result that different systematic errors are expected. We have tested the operation of the VSA with a variety of blank-field and calibrator observations and cross-checked its calibration scale against independent measurements. We find that systematic effects can be suppressed below the thermal noise level in long observations; the overall calibration accuracy of the flux density scale is 3.5 percent and is limited by the external absolute calibration scale. 
Robert A. Watson, Pedro Carreira, Kieran Cleary, Rod D. Davies,   Richard J. Davis, Clive Dickinson, Keith Grainge, Carlos M...