Witness reports of Unidentified Aerial Phenomena (UAP) occasionally associate UAP sightings with strong magnetic effects. These reports have motivated the incorporation of a magnetometer into the Galileo Project, a Harvard-led scientific collaboration whose aim is to collect and analyze data that could help elucidate the nature of UAP. Here, we present how we tested our magnetometer by comparing data recorded at our observatory in Colorado, USA, with data of a certified magnetic observatory.