This is a web map rendering Synthetic Aperture Radar (SAR) imagery from the European Space Agency's Sentinel-1 satellites.
It currently aims to cover the North Sea area as it provides a useful data source for mapping wind farms and other offshore installations for OpenStreetMap. Coverage may be extended, disk space permitting.
The Sentinel-1 SAR imagery doesn't have adequate spatial resolution for land-based mapping but it's great at detecting metallic objects at sea and provides a very high revisit rate.
This imagery can be added to JOSM or other OpenStreetMap editors by using the TMS URL:
https://sar.russss.dev/{zoom}/{x}/{-y}.png
Image data is licensed under the Sentinel data license - you are required to use the attribution "Contains Copernicus data <year of reception>".
Any copyright over image processing is released under the CC0 1.0 Universal Public Domain Dedication. You are kindly requested (but not required) to credit Russ Garrett and link to this page.