Extragalactic number counts at 100 um, free from cosmic variance
  We use data from the Disc Emission via a Bias-free Reconnaissance in the
Infrared/Submillimetre (DEBRIS) survey, taken at 100 um with the Photoconductor
Array Camera and Spectrometer instrument on board the Herschel Space
Observatory, to make a cosmic variance independent measurement of the
extragalactic number counts. These data consist of 323 small-area mapping
observations performed uniformly across the sky, and thus represent a sparse
sampling of the astronomical sky with an effective coverage of ~2.5 deg^2.
  We find our cosmic variance independent analysis to be consistent with
previous count measurements made using relatively small area surveys.
Furthermore, we find no statistically significant cosmic variance on any scale
within the errors of our data. Finally, we interpret these results to estimate
the probability of galaxy source confusion in the study of debris discs.
