def testDcrSubfilterOrder(self):
"""Test that the bluest subfilter always has the largest DCR amplitude.
"""
pixelScale = 0.2 * arcseconds
for testIter in range(self.nRandIter):
rotAngle = 360. * self.rng.rand() * degrees
azimuth = 360. * self.rng.rand() * degrees
elevation = (45. + self.rng.rand() * 40.
) * degrees # Restrict to 45 < elevation < 85 degrees
visitInfo = self.makeDummyVisitInfo(azimuth, elevation)
wcs = self.makeDummyWcs(rotAngle,
pixelScale,
crval=visitInfo.getBoresightRaDec())
dcrShift = calculateDcr(visitInfo, wcs, self.effectiveWavelength,
self.bandwidth, self.dcrNumSubfilters)
# First check that the blue subfilter amplitude is greater than the red subfilter
rotation = calculateImageParallacticAngle(visitInfo,
wcs).asRadians()
ampShift = [
dcr[1] * np.sin(rotation) + dcr[0] * np.cos(rotation)
for dcr in dcrShift
]
self.assertGreater(
ampShift[0],
0.) # The blue subfilter should be shifted towards zenith
self.assertLess(
ampShift[2],
0.) # The red subfilter should be shifted away from zenith
# The absolute amplitude of the blue subfilter should also
# be greater than that of the red subfilter
self.assertGreater(np.abs(ampShift[0]), np.abs(ampShift[2]))
def testRotationAngle(self):
"""Test that the sky rotation angle is consistently computed.
The rotation is compared to pre-computed values.
"""
cdRotAngle = 0.*degrees
azimuth = 130.*degrees
elevation = 70.*degrees
pixelScale = 0.2*arcseconds
visitInfo = self.makeDummyVisitInfo(azimuth, elevation)
wcs = self.makeDummyWcs(cdRotAngle, pixelScale, crval=visitInfo.getBoresightRaDec())
rotAngle = calculateImageParallacticAngle(visitInfo, wcs)
refAngle = -1.0848032636337364*radians
self.assertAnglesAlmostEqual(refAngle, rotAngle)
def testRotationAngle(self):
"""Test that the sky rotation angle is consistently computed.
The rotation is compared to pre-computed values.
"""
cdRotAngle = 0.*degrees
azimuth = 130.*degrees
elevation = 70.*degrees
pixelScale = 0.2*arcseconds
visitInfo = self.makeDummyVisitInfo(azimuth, elevation)
wcs = self.makeDummyWcs(cdRotAngle, pixelScale, crval=visitInfo.getBoresightRaDec())
rotAngle = calculateImageParallacticAngle(visitInfo, wcs)
refAngle = -0.9344289857053072*radians
self.assertAnglesAlmostEqual(refAngle, rotAngle, maxDiff=1e-6*radians)
def testRotationSouthZero(self):
"""Test that an observation pointed due South has zero rotation angle.
An observation pointed South and on the meridian should have zenith
directly to the North, and a parallactic angle of zero.
"""
refAngle = 0.*degrees
azimuth = 180.*degrees # Telescope is pointed South
pixelScale = 0.2*arcseconds
for testIter in range(self.nRandIter):
# Any additional arbitrary rotation should fall out of the calculation
cdRotAngle = 360*self.rng.rand()*degrees
elevation = (45. + self.rng.rand()*40.)*degrees # Restrict to 45 < elevation < 85 degrees
visitInfo = self.makeDummyVisitInfo(azimuth, elevation)
wcs = self.makeDummyWcs(cdRotAngle, pixelScale, crval=visitInfo.getBoresightRaDec(), flipX=True)
rotAngle = calculateImageParallacticAngle(visitInfo, wcs)
self.assertAnglesAlmostEqual(refAngle - cdRotAngle, rotAngle, maxDiff=coordinateTolerance)
def testRotationSouthZero(self):
"""Test that an observation pointed due South has zero rotation angle.
An observation pointed South and on the meridian should have zenith
directly to the North, and a parallactic angle of zero.
"""
refAngle = 0.*degrees
azimuth = 180.*degrees # Telescope is pointed South
pixelScale = 0.2*arcseconds
for testIter in range(self.nRandIter):
# Any additional arbitrary rotation should fall out of the calculation
cdRotAngle = 360*self.rng.rand()*degrees
elevation = (45. + self.rng.rand()*40.)*degrees # Restrict to 45 < elevation < 85 degrees
visitInfo = self.makeDummyVisitInfo(azimuth, elevation)
wcs = self.makeDummyWcs(cdRotAngle, pixelScale, crval=visitInfo.getBoresightRaDec(), flipX=True)
rotAngle = calculateImageParallacticAngle(visitInfo, wcs)
self.assertAnglesAlmostEqual(refAngle - cdRotAngle, rotAngle, maxDiff=1e-6*radians)
def testRotationFlipped(self):
"""Check the interpretation of rotations in the WCS.
"""
doFlip = [False, True]
for testIter in range(self.nRandIter):
# Any additional arbitrary rotation should fall out of the calculation
cdRotAngle = 360*self.rng.rand()*degrees
# Make the telescope be pointed South, so that the parallactic angle is zero.
azimuth = 180.*degrees
elevation = (45. + self.rng.rand()*40.)*degrees # Restrict to 45 < elevation < 85 degrees
pixelScale = 0.2*arcseconds
visitInfo = self.makeDummyVisitInfo(azimuth, elevation)
for flip in doFlip:
wcs = self.makeDummyWcs(cdRotAngle, pixelScale,
crval=visitInfo.getBoresightRaDec(),
flipX=flip)
rotAngle = calculateImageParallacticAngle(visitInfo, wcs)
if flip:
rotAngle *= -1
self.assertAnglesAlmostEqual(cdRotAngle, rotAngle, maxDiff=coordinateTolerance)
def testRotationFlipped(self):
"""Check the interpretation of rotations in the WCS.
"""
doFlip = [False, True]
for testIter in range(self.nRandIter):
# Any additional arbitrary rotation should fall out of the calculation
cdRotAngle = 360*self.rng.rand()*degrees
# Make the telescope be pointed South, so that the parallactic angle is zero.
azimuth = 180.*degrees
elevation = (45. + self.rng.rand()*40.)*degrees # Restrict to 45 < elevation < 85 degrees
pixelScale = 0.2*arcseconds
visitInfo = self.makeDummyVisitInfo(azimuth, elevation)
for flip in doFlip:
wcs = self.makeDummyWcs(cdRotAngle, pixelScale,
crval=visitInfo.getBoresightRaDec(),
flipX=flip)
rotAngle = calculateImageParallacticAngle(visitInfo, wcs)
if flip:
rotAngle *= -1
self.assertAnglesAlmostEqual(cdRotAngle, rotAngle, maxDiff=1e-6*radians)
def testDcrSubfilterOrder(self):
"""Test that the bluest subfilter always has the largest DCR amplitude.
"""
dcrNumSubfilters = 3
afwImageUtils.defineFilter("gTest", self.lambdaEff,
lambdaMin=self.lambdaMin, lambdaMax=self.lambdaMax)
filterInfo = afwImage.Filter("gTest")
pixelScale = 0.2*arcseconds
for testIter in range(self.nRandIter):
rotAngle = 360.*self.rng.rand()*degrees
azimuth = 360.*self.rng.rand()*degrees
elevation = (45. + self.rng.rand()*40.)*degrees # Restrict to 45 < elevation < 85 degrees
visitInfo = self.makeDummyVisitInfo(azimuth, elevation)
wcs = self.makeDummyWcs(rotAngle, pixelScale, crval=visitInfo.getBoresightRaDec())
dcrShift = calculateDcr(visitInfo, wcs, filterInfo, dcrNumSubfilters)
# First check that the blue subfilter amplitude is greater than the red subfilter
rotation = calculateImageParallacticAngle(visitInfo, wcs).asRadians()
ampShift = [dcr[1]*np.sin(rotation) + dcr[0]*np.cos(rotation) for dcr in dcrShift]
self.assertGreater(ampShift[0], 0.) # The blue subfilter should be shifted towards zenith
self.assertLess(ampShift[2], 0.) # The red subfilter should be shifted away from zenith
# The absolute amplitude of the blue subfilter should also
# be greater than that of the red subfilter
self.assertGreater(np.abs(ampShift[0]), np.abs(ampShift[2]))