Increasing LST tolerance, updating docstrings and fixing CHANGELOG.

CHANGELOG.md

@@ -3,12 +3,23 @@ All notable changes to this project will be documented in this file.
 
 ## [Unreleased]
 
-## [2.4.1] - 2023-10-13
-
 ### Added
 - Added a `check_surface_based_positions` positions method for verifying antenna
 positions are near surface of whatever celestial body their positions are referenced to
 (either the Earth or Moon, currently).
+
+### Changed
+- Increased the tolerance to 75 mas (equivalent to 5 ms time error) for a warning about
+values in `lst_array` not conforming to exceptations for `UVData`, `UVCal`, and `UVFlag`
+(was 1 mas) inside of `check`. Additionally, added a keyword to `check` enable the
+tolerance value to be user-specified.
+- Changed the behavior of checking of telescope location to look at the combination of
+`antenna_positions` and `telescope_location` together for `UVData`, `UVCal`, and `UVFlag`.
+Additionally, failing this check results in a warning (was an error).
+
+## [2.4.1] - 2023-10-13
+
+### Added
 - Added a `uvw_track_generator` method within `utils` for calculating the expected
 uvws (and a few other values) without needing to instantiate a whole `UVData` object.
 - Added a convenience function called `compare_value` in `UVParameter` that enables
@@ -23,14 +34,6 @@ file to the new `mwa_metafits_file` parameter.
 - Support for setting the astrometry library for various object methods including `set_lsts_from_time_array`, file read methods and others.
 - Properly round-trip the telescope frame through UVH5, UVFITS and MS files.
 
-### Changed
-- Increased the tolerance to 15 mas for a warning about values in `lst_array` not conforming
-to exceptations for `UVData`, `UVCal`, and `UVFlag` (was 1 mas) inside of `check`, additionally
-adding a keyword to enable the tolerance value to be specified.
-- Changed the behavior of checking of telescope location to look at the combination of
-`antenna_positions` and `telescope_location` together for `UVData`, `UVCal`, and `UVFlag`.
-Additionally, failing this check results in a warning (was an error).
-
 ### Fixed
 - A bug in apparent coordinate calculation that resulted in small errors/loss of
 precision due to the way times were passed when using `erfa` astrometry library.

pyuvdata/utils.py

@@ -75,8 +75,11 @@
 
 # standard angle tolerance: 1 mas in radians.
 RADIAN_TOL = 1 * 2 * np.pi * 1e-3 / (60.0 * 60.0 * 360.0)
-# standard lst time tolerance: 1 ms (15 mas in radians)
-LST_RAD_TOL = 1 * 2 * np.pi * 1e-3 / (86400.0)
+# standard lst time tolerance: 5 ms (75 mas in radians), based on an expected RMS
+# accuracy of 1 ms at 7 days out from issuance of Bulletin A (which are issued once a
+# week with rapidly determined parameters and forecasted values of DUT1), the exact
+# formula for which is t_err = 0.00025 (MJD-<Bulletin A Release Data>)**0.75 (in secs).
+LST_RAD_TOL = 2 * np.pi * 5e-3 / (86400.0)
 
 # fmt: off
 # polarization constants

pyuvdata/uvcal/uvcal.py

@@ -1216,9 +1216,11 @@ def check(
             Tolerance level at which to test LSTs against their expected values. If
             provided as a float, must be in units of radians. If set to None, the
             default precision tolerance from the `lst_array` parameter is used (1 mas).
-            Default value is 15 mas,  which is set by the predictive uncertainty in IERS
-            calculations of DUT1 (of order 1 ms), which for some observatories sets the
-            precision with which these values are written.
+            Default value is 75 mas,  which is set by the predictive uncertainty in IERS
+            calculations of DUT1 (RMS is of order 1 ms, with with a 5-sigma threshold
+            for detection is used to prevent false issues from being reported), which
+            for some observatories sets the precision with which these values are
+            written.
 
         Returns
         -------

pyuvdata/uvdata/uvdata.py

@@ -3241,9 +3241,11 @@ def check(
             Tolerance level at which to test LSTs against their expected values. If
             provided as a float, must be in units of radians. If set to None, the
             default precision tolerance from the `lst_array` parameter is used (1 mas).
-            Default value is 15 mas,  which is set by the predictive uncertainty in IERS
-            calculations of DUT1 (of order 1 ms), which for some observatories sets the
-            precision with which these values are written.
+            Default value is 75 mas,  which is set by the predictive uncertainty in IERS
+            calculations of DUT1 (RMS is of order 1 ms, with with a 5-sigma threshold
+            for detection is used to prevent false issues from being reported), which
+            for some observatories sets the precision with which these values are
+            written.
 
         Returns
         -------

pyuvdata/uvflag/uvflag.py

@@ -948,9 +948,11 @@ def check(
             Tolerance level at which to test LSTs against their expected values. If
             provided as a float, must be in units of radians. If set to None, the
             default precision tolerance from the `lst_array` parameter is used (1 mas).
-            Default value is 15 mas,  which is set by the predictive uncertainty in IERS
-            calculations of DUT1 (of order 1 ms), which for some observatories sets the
-            precision with which these values are written.
+            Default value is 75 mas,  which is set by the predictive uncertainty in IERS
+            calculations of DUT1 (RMS is of order 1 ms, with with a 5-sigma threshold
+            for detection is used to prevent false issues from being reported), which
+            for some observatories sets the precision with which these values are
+            written.
 
         Returns
         -------