diff --git a/tradedb.py b/tradedb.py
index b248ff1a..78fe19b9 100644
--- a/tradedb.py
+++ b/tradedb.py
@@ -569,7 +569,8 @@ def genSystemsInRange(self, system, ly, includeSelf=False):
                         (candidate.posY - sysY) ** 2 +
                         (candidate.posZ - sysZ) ** 2
                 )
-                cachedSystems[candidate] = dist = math.sqrt(distSq)
+                if distSq <= lySq:
+                    cachedSystems[candidate] = math.sqrt(distSq)
 
             cache.probedLy = probedLy = ly