New approach to nJy+Calib support

python/lsst/pipe/tasks/colorterms.py

@@ -104,13 +104,14 @@ def getFluxes(fluxField):
         primaryFlux, primaryErr = getFluxes(self.primary + "_flux")
         secondaryFlux, secondaryErr = getFluxes(self.secondary + "_flux")
 
-        primaryMag = u.Quantity(primaryFlux, u.Jy).to_value(u.ABmag)
-        secondaryMag = u.Quantity(secondaryFlux, u.Jy).to_value(u.ABmag)
+        primaryMag = u.Quantity(primaryFlux, u.nJy).to_value(u.ABmag)
+        secondaryMag = u.Quantity(secondaryFlux, u.nJy).to_value(u.ABmag)
 
         refMag = self.transformMags(primaryMag, secondaryMag)
         refFluxErrArr = self.propagateFluxErrors(primaryErr, secondaryErr)
 
-        refMagErr = abMagErrFromFluxErr(refFluxErrArr, primaryFlux)
+        # HACK convert to Jy until we have a replacement for this (DM-16903)
+        refMagErr = abMagErrFromFluxErr(refFluxErrArr*1e-9, primaryFlux*1e-9)
 
         return refMag, refMagErr
 

python/lsst/pipe/tasks/photoCal.py

@@ -28,7 +28,7 @@
 
 import lsst.pex.config as pexConf
 import lsst.pipe.base as pipeBase
-from lsst.afw.image import abMagFromFlux, abMagErrFromFluxErr, Calib
+from lsst.afw.image import abMagErrFromFluxErr, Calib
 import lsst.afw.table as afwTable
 from lsst.meas.astrom import DirectMatchTask, DirectMatchConfigWithoutLoader
 import lsst.afw.display as afwDisplay
@@ -306,10 +306,10 @@ def extractMagArrays(self, matches, filterName, sourceKeys):
             self.log.warn("Source catalog does not have flux uncertainties; using sqrt(flux).")
             srcInstFluxErrArr = np.sqrt(srcInstFluxArr)
 
-        # convert source instFlux from DN to an estimate of Jy
-        JanskysPerABFlux = 3631.0
-        srcInstFluxArr = srcInstFluxArr*JanskysPerABFlux
-        srcInstFluxErrArr = srcInstFluxErrArr*JanskysPerABFlux
+        # convert source instFlux from DN to an estimate of nJy
+        referenceFlux = (0*u.ABmag).to_value(u.nJy)
+        srcInstFluxArr = srcInstFluxArr * referenceFlux
+        srcInstFluxErrArr = srcInstFluxErrArr * referenceFlux
 
         if not matches:
             raise RuntimeError("No reference stars are available")
@@ -360,14 +360,16 @@ def extractMagArrays(self, matches, filterName, sourceKeys):
                               fluxField)
                 refFluxErrArr = np.sqrt(refFluxArr)
 
-            refMagArr = u.Quantity(refFluxArr, u.Jy).to_value(u.ABmag)
-            refMagErrArr = abMagErrFromFluxErr(refFluxErrArr, refFluxArr)
+            refMagArr = u.Quantity(refFluxArr, u.nJy).to_value(u.ABmag)
+            # HACK convert to Jy until we have a replacement for this (DM-16903)
+            refMagErrArr = abMagErrFromFluxErr(refFluxErrArr*1e-9, refFluxArr*1e-9)
 
         # compute the source catalog magnitudes and errors
-        srcMagArr = np.array([abMagFromFlux(sf) for sf in srcInstFluxArr])
+        srcMagArr = u.Quantity(srcInstFluxArr, u.nJy).to_value(u.ABmag)
         # Fitting with error bars in both axes is hard
         # for now ignore reference flux error, but ticket DM-2308 is a request for a better solution
-        magErrArr = abMagErrFromFluxErr(srcInstFluxErrArr, srcInstFluxArr)
+        # HACK convert to Jy until we have a replacement for this (DM-16903)
+        magErrArr = abMagErrFromFluxErr(srcInstFluxErrArr*1e-9, srcInstFluxArr*1e-9)
         if self.config.magErrFloor != 0.0:
             magErrArr = (magErrArr**2 + self.config.magErrFloor**2)**0.5
 
@@ -443,22 +445,9 @@ def run(self, exposure, sourceCat, expId=0):
 
         filterName = exposure.getFilter().getName()
 
-        def convert_refCat_to_jansky(matches):
-            """Convert fluxes in matches[*][0] (the refCat) from nJy to Jy.
-            Schema will still read nJy.
-            HACK to continue supporting Calib, which assumes Jy fluxes.
-            To be removed in DM-10156.
-            """
-            fields = [field for field in matches[0][0].schema if field.field.getUnits() == 'nJy']
-            for match in matches:
-                for field in fields:
-                    match[0][field.key] *= 1e-9
-
         # Match sources
         matchResults = self.match.run(sourceCat, filterName)
         matches = matchResults.matches
-        # HACK to support Calib for the remainder of its now brief existence.
-        convert_refCat_to_jansky(matches)
 
         reserveResults = self.reserve.run([mm.second for mm in matches], expId=expId)
         if displaySources:

tests/test_colorterm.py

@@ -133,8 +133,8 @@ def testGetCorrectedMagnitudes(self):
         flux = 100
         refCat = make_fake_refcat(center, flux)
 
-        expectMag = self.colorterm.transformMags((u.Jy*refCat['f1_flux']).to_value(u.ABmag),
-                                                 (u.Jy*refCat['f2_flux']).to_value(u.ABmag))
+        expectMag = self.colorterm.transformMags((u.nJy*refCat['f1_flux']).to_value(u.ABmag),
+                                                 (u.nJy*refCat['f2_flux']).to_value(u.ABmag))
         refMag, refMagErr = self.colorterm.getCorrectedMagnitudes(refCat, 'r')
         self.assertEqual(refMag, expectMag)
         # TODO DM-17692: Not testing the returned errors, as I do not trust `propagateFluxErrors()`

tests/test_photoCal.py

@@ -23,6 +23,7 @@
 import unittest
 
 import numpy as np
+import astropy.units as u
 
 from lsst.daf.persistence import Butler
 from lsst.meas.algorithms import LoadIndexedReferenceObjectsTask
@@ -121,7 +122,7 @@ def _runTask(self):
             refFlux = m[0].get(refFluxField)  # reference catalog flux
             if refFlux <= 0:
                 continue
-            refMag = afwImage.abMagFromFlux(refFlux)  # reference catalog mag
+            refMag = u.Quantity(refFlux, u.nJy).to_value(u.ABmag)
             instFlux = m[1].getPsfInstFlux()  # Instrumental Flux
             if instFlux <= 0:
                 continue