Item 174 - Signal flags, Portland, ca. 1800 Item 174 - Signal flags, Portland, ca. 1800 Contributed by Maine Historical Society Item 174 Zoom 4799px x 2814px - 16.0"w x 9.4"h @ 300dpi | Need a larger size? *Credit line must read: Collections of Maine Historical Society Image Info These flags were positioned atop the Portland Observatory to alert Portland's residents and shipowners of ships arriving in Portland Harbor. Lemuel Moody, who built the Portland Observatory and was the caretaker at the time this document was created may be its author. Show Details