fix(RFISensitivityMask): incorrect time range used for bright sources

The range of times for which the masking algorithm is changed did not
match up to actual times of the bright source transits.

ch_pipeline/analysis/flagging.py

@@ -191,33 +191,32 @@ def _combine_st_mad_hook(self, times):
             Mixing array as a function of time. If `True` that sample will be
             filled from the MAD, if `False` use the SumThreshold algorithm.
         """
-
-        sidereal_day = ephemeris.SIDEREAL_S * 24 * 3600
-
-        ntime = len(times)
-        start_csd = ephemeris.unix_to_csd(times[0])
-        start_ra = (start_csd - int(start_csd)) * (2.0 * np.pi)
-        ra_axis = (start_ra + (2.0 * np.pi) / ntime * np.arange(ntime)) % (2.0 * np.pi)
+        # Switch for 4 deg each side of the source
+        beam_window = np.radians(4.0)
+        SIDEREAL_DAY = ephemeris.SIDEREAL_S * 24 * 3600
 
         # Select Sun transit times
         suntt = ephemeris.solar_transit(times[0])  # Sun transit time
-        beam_window = (2.0 * np.pi) / 90.0  # 4 deg in radians for the Sun. Each side.
+
         # Mask the sun for the maximum aparent dec of ~24 deg
         ra_window = beam_window / np.cos(np.deg2rad(24))
-        time_window = ra_window / (2 * np.pi) * sidereal_day
+        time_window = ra_window / (2 * np.pi) * SIDEREAL_DAY
+
         # Time spans where we apply the MAD filter.
-        madtimes = abs(times - suntt) < time_window
+        madtimes = np.abs(times - suntt) < time_window
 
         # Select bright source transit times. Only CasA, CygA and TauA.
         sources = [ephemeris.CasA, ephemeris.CygA, ephemeris.TauA]
 
+        ra_axis = np.radians(ephemeris.lsa(times))
+
+        # Include bright point source transits in MAD times
         for src in sources:
-            src_ra = src.ra.radians
-            src_idx = np.argmin(abs(ra_axis - src_ra))
-            ra_window = beam_window / np.cos(src.dec.radians)
-            time_window = ra_window / (2 * np.pi) * sidereal_day
-            # Include bright point source transit in MAD times
-            madtimes += abs(times - times[src_idx]) < time_window
+            ra = src.ra.radians
+            dec = src.dec.radians
+            ra_window = beam_window / np.cos(dec)
+
+            madtimes |= np.abs(ra_axis - ra) < ra_window
 
         return madtimes