Merge pull request nanograv#1722 from scottransom/old_princeton

Allow very old Princeton format TOAs

src/pint/toa.py

@@ -492,7 +492,11 @@ def _parse_TOA_line(line, fmt="Unknown"):
         d["freq"] = float(line[15:24])
         d["error"] = float(line[44:53])
         ii, ff = line[24:44].split(".")
-        MJD = (int(ii), float(f"0.{ff}"))
+        ii = int(ii)
+        # For very old TOAs, see https://tempo.sourceforge.net/ref_man_sections/toa.txt
+        if ii < 40000:
+            ii += 39126
+        MJD = (ii, float(f"0.{ff}"))
         try:
             d["ddm"] = str(float(line[68:78]))
         except ValueError:

tests/test_toa_reader.py

@@ -73,6 +73,25 @@ def test_read_parkes(self):
         assert "barycenter" in ts.observatories
         assert ts.ntoas == 8
 
+    def test_read_princeton(self):
+        toaline = "6   11 1744-24 1666.0000 50852.5886574493316     25.6  8-FEB-98    0.0    1  1"
+        mjd, d = toa._parse_TOA_line(toaline)
+        assert np.isclose(mjd[0] + mjd[1], 50852.5886574493316)
+        assert d["format"] == "Princeton"
+        assert d["obs"] == "vla"
+        assert d["freq"] == 1666.0
+        assert d["error"] == 25.6
+
+    def test_read_princeton_offset1(self):
+        toaline = "6   26 1744-24 1667.0000 9064.9010416342947       6.2 26-OCT-90    0.1    1  1"
+        mjd, d = toa._parse_TOA_line(toaline)
+        assert np.isclose(mjd[0] + mjd[1], 48190.9010416342947)
+
+    def test_read_princeton_offset2(self):
+        toaline = "6   37 1744-24 1666.000010062.1379629521572       7.8 20-JUL-93   64.6    1  1"
+        mjd, d = toa._parse_TOA_line(toaline)
+        assert np.isclose(mjd[0] + mjd[1], 49188.1379629521572)
+
     def test_read_parkes_phaseoffset(self):
         # Fourth column contains non-zero phase offset
         toaline = " PUPPI_J2044+28_58852_652 432.3420  58852.7590686063892    1.00  120.75        @"