My primary use of Flickr is to post images related to my interest in signaling by reflecting sunlight from mirrors. This includes: emergency signal mirrors, heliographs, heliotropes, and the BSA event, Operation On-Target. For more information on these topics, see my galleries, or the appropriate Wikipedia articles:

en.wikipedia.org/wiki/Operation_On-Target

en.wikipedia.org/wiki/Heliograph

en.wikipedia.org/wiki/Heliotrope_(instrument)