TIL you actually can track synthesis targets with the scanner. These simaris wisps make a trail that lead right to the target but you can only see them with the scanner. :
Warframe Synthesis Scanner - How does it work? | GameWatcher
Cephalon Simaris | Magyar Warframe Wiki | Fandom
How to get Cephalon Simaris standing in Warframe
Steam Community :: Guide :: A Guide to Synthesis
Complete all 5 scans for Cephalon Simaris challenge in 10 minutes | warframe challenge guide - YouTube