Engineering and Science Highlights of the KAT-7 Radio Telescope

TL;DR

The KAT-7 radio telescope served as an engineering prototype demonstrating innovative technologies and techniques, with successful scientific applications including mapping low-brightness sources, HI halos, and pulsar monitoring, informing future telescope designs.

Contribution

This paper presents the engineering and scientific highlights of KAT-7, showcasing its technological innovations and scientific capabilities relevant to next-generation radio telescopes.

Findings

Composite dish surface performs well but is complex to fabricate without circular symmetry.

Cryogenic system with ion pump requires higher maintenance than Gifford-McMahon system.

ROACH-based correlator with SPEAD protocol functions effectively.

Abstract

The construction of the KAT-7 array in the Karoo region of the Northern Cape in South Africa was intended primarily as an engineering prototype for technologies and techniques applicable to the MeerKAT telescope. This paper looks at the main engineering and scien- tific highlights from this effort, and discusses their applicability to both MeerKAT and other next-generation radio telescopes. In particular we found that the composite dish surface works well, but it becomes complicated to fabricate for a dish lacking circular symmetry; the Stir- ling cycle cryogenic system with ion pump to achieve vacuum works but demands much higher maintenance than an equivalent Gifford-McMahon cycle system; the ROACH (Recon- figurable Open Architecture Computing Hardware)-based correlator with SPEAD (Stream- ing Protocol for Exchanging Astronomical Data) protocol data transfer works very well and KATCP (Karoo Array Telescope Control Protocol) control protocol has proven very flexible and convenient. KAT-7 has also been used for scientific observations where it has a niche in mapping low surface-brightness continuum sources, some extended HI halos and OH masers in star-forming regions. It can also be used to monitor continuum source variability, observe pulsars, and make VLBI observations