In our quest of improving OSM, the Telenav mapping team comes across various official data sources that contain valuable information for adding in OSM. Being able to use the data we find requires a tool that compares an external file with the current OSM data. In the GIS world this process is called conflation. This is where Cygnus comes in! The core role of this tool is to conflate, in a non-destructive way without deleting or degrading existing OSM data, external data with OSM. Cygnus will output a JOSM XML format file with all the changes that can be loaded in JOSM, carefully analyzed and uploaded to OSM. In this talk, we will show you how we do it, and how you can use Cygnus too.