Keywords: Heliograph-2.jpg heliograph - Signaling with heliograph near Monument 92 Alaska - Canada border International Boundary Commission Heliograph jpg 2008-06-29 06 40 UTC derivative work Macchess talk Heliograph jpg http //www noaa gov/ US National Oceanic and Atmospheric Administration Cropped Macchess Heliograph jpg PD-USGov original upload log This image is a derivative work of the following images Image Heliograph jpg licensed with PD-USGov 2005-04-03T09 15 47Z Svdmolen 1376x900 551067 Bytes <nowiki>heliograph -http //www photolib noaa gov/historic/c gs/theb1633 htm PD science</nowiki> Uploaded with derivativeFX History of engineering History of telecommunications Heliographs 1910 in Alaska |