The Simons Observatory: Large Aperature Telescope Beam Charecterization

he Simons Observatory Large Aperture Telescope (LAT) is a 6 meter telescope located at an elevation of 5200 meters in the Atacama Desert in Chile. The maps produced by the LAT will cover 60% of the sky with unprecedented sensitivity at high resolution, with five times the angular resolution and ten times the map depth of Planck . The LAT achieved first light in February 2025 with ~30,000 polarization-sensitive detectors with bands centered at 90, 150, 220, and 280 GHz. Here we present a characterization of the LAT beams in temperature and polarization from measurements of planets. Additionally, we show the impact of mirror alignment on the LAT beams along with a summary of the mirror alignment techniques.