Append to existing file

eclipswaarneming.py

@@ -10,6 +10,7 @@ Tammo Jan Dijkema, 29 June 2020
 
 import time
 import matplotlib.pyplot as plt
+import sys
 import zmq
 import struct
 import numpy as np
@@ -30,9 +31,6 @@ logger.setLevel(level=logging.INFO)
 signal = 0.
 prev_signal = 0.
 
-datafile = open(f"data{int(Time.now().unix)}.txt", "w")
-print("Time (UTC),Tracker,Offset az (deg),Offset el(deg),azimuth from north (deg),elevation (deg),signal 70cm,signal 23cm", file=datafile)
-
 def signal_thread():
     global signal
     context = zmq.Context()
@@ -68,8 +66,12 @@ prev_points = None
 separation = None
 maxsignal = 0.
 
-scatterplot = ax.scatter([], [], s=3, color='black')
-calplot = ax.scatter([], [], s=3, color='lightgrey')
+file_dates = []
+file_data = []
+file_caldata = []
+
+scatterplot = ax.scatter(file_dates, file_data, s=3, color='black')
+calplot = ax.scatter(file_dates, file_caldata, s=3, color='lightgrey')
 ax.xaxis.set_major_formatter(mdates.DateFormatter('%H:%M'))
 
 eclipse_starttime = Time("2021-06-10T11:21") + 2*u.hour
@@ -81,6 +83,12 @@ if starttime < eclipse_endtime < starttime + 3*u.hour:
     ax.axvline(eclipse_endtime.datetime, linestyle='--', linewidth=1, color='lightgrey')
     ax.text(eclipse_endtime.datetime,0.1,'Einde: '+eclipse_endtime.isot[11:16],rotation=90, color='black', transform=ax.get_xaxis_transform())
 
+if len(sys.argv) == 1:
+    datafile = open(f"data{int(Time.now().unix)}.txt", "w")
+    print("Time (UTC),Tracker,Offset az (deg),Offset el(deg),azimuth from north (deg),elevation (deg),signal 70cm,signal 23cm", file=datafile)
+else:
+    datafile = open(f"{sys.argv[1]}", "a")
+
 while True:
     time.sleep(0.2)
     if signal == prev_signal: