def read_cold(names, ave_cold, minel, minGLat, maxGlat):
"""
read_cold() reads all files and averages selected files with high elevation and
galactic Latitude.
Inputs:
minel minimum elevation to accept for cold load
minGLat minimum galactic latitude
maxGlat maximum galactic latitude
"""
# flag starting a new sum of cold (high elevation and galactic latitude) obs
ncold = 0
rs = radioastronomy.Spectrum()
# now average coldest data for calibration
for filename in names:
rs.read_spec_ast(filename)
rs.azel2radec() # compute ra,dec from az,el
if rs.telel < lowel: #if elevation too low for a cold load obs
continue
# note this test excludes low galactic latitude ranges
if rs.gallat > maxGlat or rs.gallat < minGlat:
if ncold == 0:
firstutc = rs.utc
lastutc = rs.utc
ave_cold, rs, ncold, firstutc, lastutc = \
average_spec( ave_cold, rs, ncold, firstutc, lastutc)
# end of all files to average
if ncold < 1:
print("No high galactic latitude data: can not calibrate")
exit()
else:
ave_cold, ncold = normalize_spec(ave_cold, ncold, firstutc, lastutc)
if flagRfi:
yv = ave_cold.ydataA
xv = ave_cold.xdata * 1.E-6
cv = interpolate.lines(linelist, linewidth, xv, yv) # interpolate rfi
ave_cold.ydataA = cv
if doFold:
ave_cold.foldfrequency()
print("Found %3d High Galactic Latitude spectra" % (ncold))
return ave_cold, ncold
def read_hot(names, ave_hot):
"""
read_hot() reads in all files in the names list and averages hot load
observations. The hot load file is returned.
While reading the files, the minmum elevation and galactic latitudes are recorded
"""
rs = radioastronomy.Spectrum()
nhot = 0 # init count of hot files
minGlat = +90.
maxGlat = -90.
minel = 200.
maxel = -200.
# now run through and find hot and cold loads obs
for filename in names:
parts = filename.split('/')
nparts = len(parts)
if nparts == 1:
aname = parts[0]
else:
aname = parts[nparts - 1]
parts = aname.split('.')
nparts = len(parts)
if nparts < 2:
print('File is not an astronomy file: ', filename)
continue
else:
extension = parts[nparts - 1]
extension = extension.upper()
if (extension != 'HOT') and (extension != 'AST') and (extension !=
'CLD'):
print('Extension not recognized : ', parts[nparts - 1])
continue
rs.read_spec_ast(filename)
rs.azel2radec() # compute ra,dec from az,el
# if a hot load observation
if rs.telel < 0:
if nhot == 0:
firstutc = rs.utc
lastutc = rs.utc
# accumulate spectra
ave_hot, rs, nhot, firstutc, lastutc = \
average_spec( ave_hot, rs, nhot, firstutc, lastutc)
else: # else above horizon, find min, max galactic latitudes
if rs.gallat > maxGlat:
maxGlat = rs.gallat
if rs.gallat < minGlat:
minGlat = rs.gallat
if minel > rs.telel:
minel = rs.telel
if maxel < rs.telel:
maxel = rs.telel
# end for all files
if nhot > 0:
print("Found %3d Hot load observations" % (nhot))
ave_hot, nhot = normalize_spec(ave_hot, nhot, firstutc, lastutc)
else:
print("No Hot load data, can not calibrate")
exit()
# do more cleanup on spectra for RFI
if flagRfi:
yv = copy.deepcopy(ave_hot.ydataA)
xv = ave_hot.xdata * 1.E-6
hv = interpolate.lines(linelist, linewidth, xv, yv) # interpolate rfi
ave_hot.ydataA = hv
# now obsolete option to fold spectra, when a problem with SDR I-Q balance
if doFold:
ave_hot.foldfrequency()
return ave_hot, minel, maxel, minGlat, maxGlat
def findzero( names, gain, vel, azoffset, eloffset, avetimesec):
lastgain = 0.
global nprint
# flag start of search for a latitude zero crossing
ncrossings = -1
crossingsum = 0.
lastgallat = -100.
lastsum = 0.
nData = len(vel)
minGlat = +90.
maxGlat = -90.
nhot = 0 # number of obs with el < 0
ncold = 0
nhigh = 0 # highest galactic latitude
lastfreq = 0.
lastbw = 0.
lastgain = 0.
lastel = 0.
lastaz = 0.
firstrun = True
avetime = datetime.timedelta(seconds=avetimesec)
firstgallon = -1.
ncrossings = 0
nread = 0
# now read through all data and average cold sky obs
for filename in names:
parts = filename.split('/')
nparts = len(parts)
aname = parts[nparts-1]
parts = aname.split('.')
aname = parts[0]
extension = parts[1]
parts = aname.split('T')
date = parts[0]
time = parts[1]
time = time.replace('_', ':') # put time back in normal hh:mm:ss format
# exclude hot load data for averaging
if extension == 'hot':
continue
rs = radioastronomy.Spectrum()
# print filename
rs.read_spec_ast(filename)
rs.telaz = rs.telaz + azoffset
rs.telel = rs.telel + eloffset
rs.azel2radec() # compute ra,dec from az,el
# if a sky observation and close to galactic plane
if rs.telel > 0. and (rs.gallat > -5.0 and rs.gallat < 5.0) :
# if first time reading data, set obs parameters
if lastfreq == 0.:
lastfreq = rs.centerFreqHz
lastbw = rs.bandwidthHz
lastgain = rs.gains[0]
lastaz = rs.telaz
lastel = rs.telel
cold = copy.deepcopy( rs)
ncold = 0
timesum = 0.
firstutc = cold.utc
lastutc = cold.utc
newAzEl = (lastaz != rs.telaz) or (lastel != rs.telel)
if newAzEl and nprint < 5:
print 'Must keep az,el constant to find pointing offsets!'
print 'Last %7.2f,%7.2f; New: %7.2f,%7.2f' % (lastaz, lastel, rs.telaz, rs.telel)
lastaz = rs.telaz
lastel = rs.telel
nprint = nprint + 1
break
if ncold > 1:
# time difference is between mid-points of integrations
dt = rs.utc - cold.utc
# add the time since midpoint of latests
dt = dt + datetime.timedelta(seconds=rs.durationSec)
lastutc = rs.utc
# if time to average (or end of all files)
if (dt > avetime) or (filename == sys.argv[nargs-1]):
cold.ydataA = cold.ydataA/float(timesum)
# have complicated steps to simple get the average time.
deltatime = endtime - starttime
aveutc,duration = radioastronomy.aveutcs( firstutc, lastutc)
cold.utc = aveutc
cold.azel2radec() # recompute coordinates for average time
ra = cold.ra
dec = cold.dec
gallat = cold.gallat
gallon = cold.gallon
if ncrossings < 0:
lastgallat = gallat
ncrossings = 0
crossingsum = 0.
xv = cold.xdata * 1.E-6
yv = cold.ydataA * scalefactor
yv = interpolate.lines( linelist, linewidth, xv, yv) # interpolate rfi
xmin = min(xv)
xmax = max(xv)
count = cold.count
note = cold.noteA
#print('%s' % note)
ncolor = min(nmax-1, nplot)
tsky = np.zeros(nData) # initialize arrays
for jjj in range (0, nData):
tsky[jjj] = yv[jjj]/gain[jjj]
imin, imax = velocity_to_indicies( vel, minvel, maxvel)
ymed = np.median(tsky[imin:imax])
ya = np.median(tsky[(imin-10):(imin+10)])
yb = np.median(tsky[(imax-10):(imax+10)])
slope = (yb-ya)/(imax-imin)
nFit = 20
baseline = fit_baseline( vel, tsky, imin, imax, nFit)
tsky = tsky - baseline
ymin = min(tsky[imin:imax])
ymax = max(tsky[imin:imax])
thesum = compute_sum( minvel, maxvel, ra, dec, gallon, gallat, vel, tsky, ncold)
# finallly if this is a latitude crossing sum.
if ((lastgallat < 0. and gallat > 0.) or (lastgallat > 0. and gallat < 0.)) and lastgallat > -100.:
if abs(gallat) < 5.:
# if first crossing, init sum
if ncrossings == 0:
ncrossings = 1
crossingsum = thesum
# print 'Zero Latitude: %7.1f %7.1f: %10.0f, %10.0f' % (lastgallat, gallat, lastsum, thesum)
else:
# else average crossings
ncrossings = ncrossings + 1
crossingsum = crossingsum + thesum
if abs(lastgallat) < 5.:
if ncrossings == 0:
ncrossings = 1
crossingsum = lastsum
# print 'Zero Latitude: %7.1f %7.1f: %10.0f, %10.0f' % (lastgallat, gallat, lastsum, thesum)
else:
# else average crossings
ncrossings = ncrossings + 1
crossingsum = crossingsum + lastsum
lastgallat = gallat
lastsum = thesum
# computation done, start sum over gain
ncold = 0
# if this was a new obs; restart the sums
if ncold == 0:
cold = copy.deepcopy(rs) # initial spectrum is one just read
starttime = cold.utc
endtime = starttime
ncold = 1
# sums are weighted by durations
crossZero = False
crossZeroLat = False
crossZeroRa = False
firstlon = rs.gallon # try to keep track of crossing zero in angular coordinates
firstra = rs.ra #
cold.ydataA = rs.ydataA * cold.durationSec
# keep track of observing time for weighted sum
timesum = rs.durationSec
else: # else not enough time yet, average cold data
# fix wrap of longitudes
cold.count = cold.count + rs.count
ncold = ncold + 1
cold.ydataA = cold.ydataA + (rs.ydataA * rs.durationSec)
cold.ra = cold.ra + (rs.ra * cold.durationSec)
cold.dec = cold.dec + (rs.dec * cold.durationSec)
cold.gallon = cold.gallon + (rs.gallon * rs.durationSec)
cold.gallat = cold.gallat + (rs.gallat * rs.durationSec)
# keep track of observing time for weighted sum
endtime = rs.utc
timesum = timesum + rs.durationSec
# end if not a enough time
# end if a cold file
#end for all files to sum
if ncrossings > 0:
crossingsum = crossingsum/float(ncrossings)
return crossingsum
if (dt > avetime) or newObs or allFiles:
if doDebug:
medianData = np.median(ave_spec.ydataA[n6:n56])
print("Average duration: %7.1f, Median: %8.3f" %
(ave_spec.durationSec, medianData))
# not calibrating hot load observations.
if ave_spec.telel < 0.:
# Reset the ncold count and restart sum
nave = 0
continue
ave_spec, nave = normalize_spec(ave_spec, nave, firstutc, lastutc)
xv = ave_spec.xdata * 1.E-6 # covert to MHz
yv = ave_spec.ydataA
if flagRfi:
yv = interpolate.lines(linelist, linewidth, xv,
yv) # interpolate rfi
xmin = min(xv)
xmax = max(xv)
xallmin = min(xmin, xallmin)
xallmax = max(xmax, xallmax)
count = ave_spec.count
note = ave_spec.noteA
#print('%s' % note)
ncolor = min(nmax - 1, nplot)
tsky, vel = compute_tsky_hotcold(xv, yv, hv, cv, thot, tcold)
# get tsys from averages of ends of spectra
tSys = np.median(tsky[n6:n56])
tStdA = np.std(tsky[n6:n26])
tStdB = np.std(tsky[n46:n56])
def findhotgain( names, avetimesec):
lastgain = 0.
# flag start of search for a latitude zero crossing
ncrossings = -1
crossingsum = 0.
lastgallat = -100.
lastsum = 0.
minGlat = +90.
maxGlat = -90.
nhot = 0 # number of obs with el < 0
ncold = 0
nhigh = 0 # highest galactic latitude
lastfreq = 0.
lastbw = 0.
lastgain = 0.
lastel = 0.
lastaz = 0.
firstrun = True
for filename in names:
rs = radioastronomy.Spectrum()
rs.read_spec_ast(filename)
rs.telel = rs.telel + eloffset
rs.telaz = rs.telaz + azoffset
rs.azel2radec() # compute ra,dec from az,el
if rs.gains[0] != lastgain:
if lastgain != 0:
print 'Gain Change: ', lastgain, ' -> ', rs.gains[0]
lastgain = rs.gains[0]
if rs.telel < 0:
if nhot == 0:
hot = copy.deepcopy( rs)
nhot = 1
else:
hot.ydataA = hot.ydataA + rs.ydataA
hot.count = hot.count + rs.count
nhot = nhot + 1
else: # else above horizon, find min, max galactic latitudes
if rs.gallat > maxGlat:
maxGlat = rs.gallat
if rs.gallat < minGlat:
minGlat = rs.gallat
if nhot > 0:
hot.ydataA = scalefactor * hot.ydataA / float(nhot)
print "Found %3d hot load obs" % nhot
else:
print "No hot load data, can not calibrate"
exit()
xv = hot.xdata * 1.E-6
yv = hot.ydataA
nData = len(xv)
hv = interpolate.lines( linelist, linewidth, xv, yv) # interpolate rfi
print 'Min,Max Galactic Latitudes %7.1f,%7.1f (d)' % (minGlat, maxGlat)
# assume only a limited range of galactic latitudes are available
# not range about +/-60.
use60Range = False
# all galactic latitudes above +/-60d can be used
if minGlat < -60. or maxGlat > 60.:
minGlat = -60.
maxGlat = 60.
else: # else no high galactic latitude data
# use highest galactic latitudes - +/-5.degrees
if -minGlat > maxGlat: # if negative latitudes higher
minGlat = minGlat + 5.
maxGlat = 90.
else: # else positive latitudes higher
maxGlat = maxGlat - 5.
minGlat = -90.
outnames = names
nout = 0
# now average coldest data for calibration
for filename in names:
rs = radioastronomy.Spectrum()
rs.read_spec_ast(filename)
rs.telaz = rs.telaz + azoffset
rs.telel = rs.telel + eloffset
rs.azel2radec() # compute ra,dec from az,el
if rs.telel < 0:
continue
if rs.gallat > maxGlat or rs.gallat < minGlat:
if nhigh == 0:
high = copy.deepcopy( rs)
high.ydataA = rs.ydataA
nhigh = 1
else:
high.ydataA = high.ydataA + rs.ydataA
high.count = high.count + rs.count
nhigh = nhigh + 1
else:
# if here, then only these names will be used to find zero crossings
outnames[nout] = filename
nout = nout + 1
if nhigh < 1.:
print "No high galactic latitude data: can not calibrate"
exit()
else:
high.ydataA = scalefactor * high.ydataA/nhigh
print "Found %d High Galactic Latidue spectra" % (nhigh)
yv = high.ydataA
cv = interpolate.lines( linelist, linewidth, xv, yv) # interpolate rfi
# finally compute gain on a channel by chanel basis
gain = np.zeros(nData)
vel = np.zeros(nData)
for iii in range(nData):
gain[iii] = (hv[iii] - cv[iii])/(thot - tcold)
vel[iii] = c * (nuh1 - xv[iii])/nuh1
# now interpolate over galactic velocities
gain = interpolate_range( minvel, maxvel, vel, gain)
if nout > 0:
outnames = outnames[0:(nout-1)]
else:
print 'No low latitude file names left!'
exit()
return gain, vel, outnames