Short Spacing Synthesis from a Primary Beam Scanned Interferometer

TL;DR

This paper introduces a novel method using a short-baseline interferometer to fill the unsampled hole in the (u,v)-plane of aperture synthesis, forming the basis for modern mosaicing algorithms in radio astronomy.

Contribution

It proposes an alternative to single-dish scans for short spacing data, utilizing a short-baseline interferometer for more uniform and efficient sampling.

Findings

The technique enables effective short spacing data acquisition.

It ensures uniformity in instrumental characteristics.

It underpins current mosaicing algorithms in radio astronomy.

Abstract

Aperture synthesis instruments providing a generally highly uniform sampling of the visibility function often leave an unsampled hole near the origin of the (u,v)-plane. In this paper, originally published in 1979, we first describe the common solution of retrieving the information from scans made with a large single-dish telescope. However, this is not the only means by which short spacing visibility data can be obtained. We propose an alternative technique that employs a short-baseline interferometer to scan the entire primary beam area. The obvious advantage is that a short-baseline pair from the synthesis instrument can be used, ensuring uniformity in instrumental characteristics. This technique is the basis for the mosaicing algorithms now commonly used in aperture synthesis radio astronomy imaging.