{"id":19862,"date":"2025-03-07T17:17:59","date_gmt":"2025-03-07T18:17:59","guid":{"rendered":"https:\/\/museu-angra.cultura.azores.gov.pt\/others\/historical-pieces\/heliograph-m-938-portuguese-model\/"},"modified":"2025-12-31T10:41:34","modified_gmt":"2025-12-31T11:41:34","slug":"heliograph-m-938-portuguese-model","status":"publish","type":"page","link":"https:\/\/museu-angra.cultura.azores.gov.pt\/en\/others\/historical-pieces\/heliograph-m-938-portuguese-model\/","title":{"rendered":"Heliograph m\/938, Portuguese Model"},"content":{"rendered":"\n<div class=\"wp-block-media-text has-media-on-the-right is-stacked-on-mobile is-vertically-aligned-top\" style=\"grid-template-columns:auto 40%\"><div class=\"wp-block-media-text__content\">\n<p><p data-start=\"12\" data-end=\"187\">Conceptually, a heliograph or optical telegraph uses the reflection of sunlight in a mirror to communicate between two points in line of sight, usually employing Morse code.<\/p>&#13;\n<p data-start=\"189\" data-end=\"611\">This model was developed in Portugal and produced from 1938, first at the General Engineering Workshops and later at the Military Factory of Bra\u00e7o de Prata. It is portable and can communicate over several kilometers, depending on visibility and sunlight intensity. Using a system of manually operated metal shutters, the sunlight reflection can be exposed or concealed, allowing messages to be transmitted in Morse code.<\/p>&#13;\n<p data-start=\"613\" data-end=\"945\" data-is-last-node=\"\" data-is-only-node=\"\">In Portugal, heliographs have been used for military communications since the 19th century. By 1899, there was a national network of fixed heliographs (which could be supplemented by portable units) covering up to two-thirds of continental Portugal. This device is part of the Military Collection of the Museum of Angra do Hero\u00edsmo.<\/p><\/p>\n<\/div><figure class=\"wp-block-media-text__media\"><img loading=\"lazy\" decoding=\"async\" width=\"630\" height=\"400\" src=\"https:\/\/museu-angra.cultura.azores.gov.pt\/wp-content\/uploads\/2025\/03\/banner-26.jpg\" alt=\"\" class=\"wp-image-12420 size-full\" srcset=\"https:\/\/museu-angra.cultura.azores.gov.pt\/wp-content\/uploads\/2025\/03\/banner-26.jpg 630w, https:\/\/museu-angra.cultura.azores.gov.pt\/wp-content\/uploads\/2025\/03\/banner-26-300x190.jpg 300w\" sizes=\"auto, (max-width: 630px) 100vw, 630px\" \/><\/figure><\/div>\n","protected":false},"excerpt":{"rendered":"<p>Conceptually, a heliograph or optical telegraph uses the reflection of sunlight in a mirror to communicate between two points in line of sight, usually employing Morse code. &#13; This model was developed in Portugal and produced from 1938, first at the General Engineering Workshops and later at the Military Factory of Bra\u00e7o de Prata. It [&hellip;]<\/p>\n","protected":false},"author":5,"featured_media":0,"parent":19114,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-19862","page","type-page","status-publish","hentry"],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.5 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Heliograph m\/938, Portuguese Model - Museum of Angra do Heroismo<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/museu-angra.cultura.azores.gov.pt\/en\/others\/historical-pieces\/heliograph-m-938-portuguese-model\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Heliograph m\/938, Portuguese Model - Museum of Angra do Heroismo\" \/>\n<meta property=\"og:description\" content=\"Conceptually, a heliograph or optical telegraph uses the reflection of sunlight in a mirror to communicate between two points in line of sight, usually employing Morse code. &#013; This model was developed in Portugal and produced from 1938, first at the General Engineering Workshops and later at the Military Factory of Bra\u00e7o de Prata. 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