  We developed two different point spread function (PSF) analysis techniques
for discovering wide separation binary asteroids in wide field surveys. We then
applied these techniques to images of main belt asteroids in the 4 to 60 km
size range captured by Pan-STARRS1. Johnston (2019) lists fewer than 10 known
binaries in this size range with separations greater than 10% of the primary's
Hill radius, so discovering more wide binary asteroids is crucial for
understanding the limits of binary stability and improving our knowledge of
asteroid masses. We analyzed each image by: i) comparing the major axis
orientation of the asteroid's elliptical PSF to its non-sidereal rate on the
sky, and ii) comparing the one-dimensional median profile created by collapsing
the image along the asteroid's direction of motion to that of nearby field
stars. For both methods, we flagged any results that deviated significantly
from the expected measurements of single asteroids, and those targets with the
most flags were identified as binary candidates for confirmation with
high-acuity imaging.
