MMA Memo #180

Imaging With Heterogeneous Arrays

M.C.H. Wright [1]

August 21, 1997

Keywords: imaging algorithms, mosaicing, heterogeneous array

This memo briefly reviews some considerations for imaging with aperture synthesis arrays containing mixed antenna sizes. At millimeter wavelengths, where mosaicing observations are important, the effect of the mixed primary beams is significant. For mosaicing observations, the sensitivity depends on the number and diameter of antennas with each primary beam type. The array configuration can be optimized to use the different antenna sizes, and depends quite strongly on the source structure. Data sampling rates are set by both the largest and smallest antenna diameter, and are larger than for an equivalent homogeneous array. The negative primary beam from mixed antenna baselines may be a problem in the mosaicing algorithms. Conceivably it might also serve to knit together the mosaic by providing different weightings of the overall image. The dynamic range of mosaiced observations is often limited by pointing errors. Pointing is more of a problem for larger antennas, but the mixed primary beam patterns may make it easier to implement a pointing self-calibration algorithm. Mosiacing with mixed antenna baselines needs detailed study.

[1] BIMA

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Last modified: 09 December, 1999