Harlan House - Credit: Wikimedia Commons
Harlan House - Credit: Wikimedia Commons
Star Gazers' Stone located on Star Gazers' Farm near Embreeville, Pennsylvania, USA, marks the site of a temporary observatory established in January 1764 by Charles Mason and Jeremiah Dixon which they used in their survey of the Mason-Dixon line. The stone was placed by Mason and Dixon about north of the Harlan House, which was used as a base of operations by Mason and Dixon through the four-and-a-half-year-long survey. Selected to be about west of the then southernmost point in Philadelphia, the observatory was used to determine the precise latitude of its location. The latitude of the Maryland-Pennsylvania border was then set to be south of the point in Philadelphia. The farm, including the house and stone, were listed on the National Register of Historic Places on May 9, 1985. In 2013 construction was completed on a parking area to allow public access to Star Gazers Stone. Read more on Wikipedia
Source: en.wikipedia.org