The Very Small Array (VSA) was a 14-element interferometric radio telescope operating between 26 and 36 GHz that is used to study the cosmic microwave background radiation.

[1][2] The telescope was comparable in terms of capabilities to several other CMB experiments, including the balloon-based BOOMERanG and MAXIMA, and the ground-based DASI and CBI.

[3] The telescope consists of 14 elements (yielding 91 baselines), each of which have a horn reflector antenna focusing astrophysical signals into individual receivers (pseudomorphic HFET amplifiers, with a system temperature around 25 K and a physical temperature of 12 K,[1] based on an NRAO design).

[9] It also includes two 3.7 m radio telescopes, also working at 30 GHz,[10] which are dedicated to monitoring foreground sources.

[2] As the VSA is an interferometer, it directly measures the angular power spectrum of the CMB, rather than having to construct a map of the sky first.

[12] These observations were taken at the highest frequency of the telescope, centered at 34 GHz, to reduce foreground contamination.

The sections of the sky observed were located within the previously-observed fields, with the measurements being both more accurate and in greater detail.