From 2b5985dff8284cbb98f21c60629a6f3147cc479d Mon Sep 17 00:00:00 2001
From: Cees Bassa <cbassa@gmail.com>
Date: Sun, 4 Mar 2018 10:23:12 +0100
Subject: [PATCH] Do not fit polynomials if no range in time

---
 python/extract_tracks.py | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/python/extract_tracks.py b/python/extract_tracks.py
index c7cde0f..6709359 100644
--- a/python/extract_tracks.py
+++ b/python/extract_tracks.py
@@ -162,6 +162,10 @@ def extract_tracks(fname,trkrmin,drdtmin,trksig,ntrkmin):
             tmid=0.5*(tmax+tmin)
             mjd=ff.mjd+tmid/86400.0
 
+            # Skip if no variance in time
+            if np.std(t-tmid)==0.0:
+                continue
+            
             # Very simple polynomial fit; no weighting, no cleaning
             px=np.polyfit(t-tmid,x,1)
             py=np.polyfit(t-tmid,y,1)