The OmegaWhite Survey for Short Period Variable Stars VI. Open Clusters
  Using light curves with $\sim$3 min cadence and a duration of 2 hrs made
using the OmegaWhite survey, we present the results of a search for
short-period variable stars in the field of 20 open clusters. We identified 92
variable stars in these fields. Using a range of cluster member catalogues and
Gaia EDR3 data, we have determined that 10 are cluster members and 2 more are
probable members. Based on their position on the Gaia HRD and their photometric
periods, we find that most of these are $\delta$ Sct stars. We obtained
low-resolution optical spectroscopy of some of these cluster members and field
stars. We discuss the cluster variable stars in the context of $\delta$ Sct
stars in other open clusters.
