From 0099c353e73a3e7d1bb28a505a1deae36ee04f36 Mon Sep 17 00:00:00 2001 From: Brandon Rhodes Date: Sun, 19 Jul 2020 06:06:02 -0400 Subject: [PATCH] Improve precision of sidereal time equinox method This does not affect any tests, but seems worth carrying through as I am otherwise trying to improve precision in Earth rotation. --- skyfield/earthlib.py | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/skyfield/earthlib.py b/skyfield/earthlib.py index 1928481..6e5c584 100644 --- a/skyfield/earthlib.py +++ b/skyfield/earthlib.py @@ -139,7 +139,7 @@ def sidereal_time(t): # Precession-in-RA terms in mean sidereal time taken from third # reference, eq. (42), with coefficients in arcseconds. - t = (t.tdb - T0) / 36525.0 + t = (t.whole - T0 + t.tdb_fraction) / 36525.0 st = ( 0.014506 + (((( - 0.0000000368 * t - 0.000029956 ) * t