Compute ERA from LST for megacam

python/lsst/obs/cfht/makeMegacamRawVisitInfo.py

@@ -23,6 +23,8 @@
 from __future__ import division
 from __future__ import print_function
 
+import astropy.units
+
 from lsst.afw.coord import Coord, IcrsCoord, Observatory, Weather
 from lsst.obs.base import MakeRawVisitInfo
 
@@ -61,6 +63,9 @@ def setArgDict(self, md, argDict):
             self.popFloat(md, "PRESSURE")*100.0,  # 100 Pascal per millibar
             self.popFloat(md, "RELHUMID"),
         )
+        # Using LST to compute ERA until we get UT1 (see: DM-8053)
+        LST = self.popAngle(md, "LST-OBS", units=astropy.units.h)
+        argDict['era'] = self.eraFromLstAndLongitude(LST, argDict["observatory"].getLongitude())
 
     def getDateAvg(self, md, exposureTime):
         """Return date at the middle of the exposure

tests/testButler.py

@@ -76,6 +76,9 @@ def setUp(self):
         self.weath_airTemperature = 0.90
         self.weath_airPressure = 617.65*100  # 100 Pascal/millibar
         self.weath_humidity = 39.77
+        # NOTE: if we deal with DM-8053 and get UT1 implemented, ERA will change slightly.
+        lst = 104.16591666666666*degrees
+        self.era = lst - self.obs_longitude
 
     def tearDown(self):
         del self.butler
@@ -126,6 +129,7 @@ def testRaw(self):
 
             visitInfo = raw.getInfo().getVisitInfo()
             self.assertAlmostEqual(visitInfo.getDate().get(), self.dateAvg.get())
+            self.assertEqual(visitInfo.getEra(), self.era)
             self.assertAlmostEqual(visitInfo.getExposureTime(), self.exposureTime)
             self.assertAlmostEqual(visitInfo.getDarkTime(), self.darkTime)
             self.assertCoordsNearlyEqual(visitInfo.getBoresightRaDec(), self.boresightRaDec)