Mance Mark V Heliograph : 無料・フリー素材/写真
Mance Mark V Heliograph / signal mirror
| ライセンス | クリエイティブ・コモンズ 表示 2.1 |
|---|---|
| 説明 | This is a Mance Mark V Heliograph set up in Simplex (single-mirror) mode. A heliograph is a signalling device that uses modulated flashes of sunlight reflected by mirrors to signal over long distances (easily 30 miles). The British Commonwealth standardized on the Mance design. Mance invented his heliograph in 1869, it was adopted by the Indian Government in 1875, and it was used more and more widely thereafter. While their use began to wane after the invention of radio ca. 1900, they were still widely manufactured and issued in World War II, which is probably when this heliograph was issued. |
| 撮影日 | 2013-06-01 07:07:57 |
| 撮影者 | signal mirror |
| タグ | |
| 撮影地 | |
| カメラ | DMC-FZ28 , Panasonic |
| 露出 | 0.1 sec (1/10) |
| 開放F値 | f/2.8 |