We apply two methods to estimate the 21-cm bispectrum from data taken within the Epoch of Reionisation (EoR) project of the Murchison Widefield Array (MWA). Using data acquired with the Phase II compact array allows a direct bispectrum estimate to be undertaken on the multiple redundantly spaced triangles of antenna tiles, as well as an estimate based on data gridded to the uv-plane. The direct and gridded bispectrum estimators are applied to 21 h of high-band (167–197 MHz; z = 6.2–7.5) data from the 2016 and 2017 observing seasons. Analytic predictions for the bispectrum bias and variance for point-source foregrounds are derived. We compare the output of these approaches, the foreground contribution to the signal, and future prospects for measuring the bispectra with redundant and non-redundant arrays. We find that some triangle configurations yield bispectrum estimates that are consistent with the expected noise level after 10 h, while equilateral configurations are strongly foreground-dominated. Careful choice of triangle configurations may be made to reduce foreground bias that hinders power spectrum estimators, and the 21-cm bispectrum may be accessible in less time than the 21-cm power spectrum for some wave modes, with detections in hundreds of hours.

While the summit of the Antarctic Plateau has long been expected to harbor the best ground-based sites for terahertz (THz) frequency astronomical investigations, it is only recently that direct observations of exceptional THz atmospheric transmission and stability have been obtained. These observations, in combination with recent technological advancements in astronomical instrumentation and autonomous field platforms, make the recognition and realization of terahertz observatories on the high plateau feasible and timely. Here, we will explore the context of terahertz astronomy in the era of Herschel, and the crucial role that observatories on the Antarctic Plateau can play. We explore the important scientific questions to which observations from this unique environment may be most productively applied. We examine the importance and complementarity of Antarctic THz astronomy in the light of contemporary facilities such as ALMA, CCAT, SOFIA and (U)LDB ballooning. Finally, building from the roots of THz facilities in Antarctica to present efforts, we broadly highlight future facilities that will exploit the unique advantages of the Polar Plateau and provide a meaningful, lasting astrophysical legacy.