A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: David Pike
Date: 2020 Oct 22, 10:10 -0700
Bill I could be wrong. I often am, but I’ve a feeling there are two types of night sensitive devices, active and passive. Active IR must be range limited like RADAR. Passive devices might be simple PIR motion sensors, which detect changes in IR with time and can be used to turn on security lights etc. I took the one off my drive, because it started talking to the one in the drive of the house opposite. They started taking it in turn to switch each other on and off.
Then there are light intensifiers which amplify existing radiation. Depending upon complexity and cost, it seems these are less range limited, so they might be able to show the horizon especially at sea at night. I found this on YouTube https://www.youtube.com/watch?v=N_mUR2puydc but I suspect It’s the deluxe $$$ version. DaveP