def obs_lat_from_name(observatory):
if observatory in OBSERVATORY_ALIASES:
obs_string = OBSERVATORY_ALIASES[observatory]
else:
obs_string = observatory
obs_id, obs_name, obs_long, obs_lat, obs_height = sla_obs(0, obs_string)
return coord.Latitude(obs_lat, u.radian)
def azza_to_radec(az, za, MJD, fctr=350.0, atm=1010.0, temp=283.0, humid=0.5, scope='GBT'):
"""
azza_to_radec(az, za, MJD):
Return RA and DEC (J2000 in deg) from AZ and ZA (in deg) at MJD. Keyword params
are fctr=350.0, atm=1010.0, temp=283.0, humid=0.5, scope='GBT'.
"""
scope, x, lon, lat, hgt = s.sla_obs(0, scope)
microns = 3e8/(fctr*1e6)*1e6
app_rarad, app_decrad = s.sla_oap('a',az*DEGTORAD,za*DEGTORAD,MJD,
0.0,-lon,lat,hgt,0.0,0.0,temp,atm,humid,microns,0.0065)
ra2000, dec2000 = s.sla_amp(app_rarad, app_decrad, MJD, 2000.0)
return ra2000*RADTODEG, dec2000*RADTODEG
def radec_to_azza(ra, dec, MJD, fctr=350.0, atm=1010.0, temp=283.0, humid=0.5, scope='GBT'):
"""
redec_to_azza(ra, dec, MJD):
Return AZ and ZA (in deg) from RA and DEC (J2000 in deg) at MJD. Keyword params
are fctr=350.0, atm=1010.0, temp=283.0, humid=0.5, scope='GBT'.
"""
scope, x, lon, lat, hgt = s.sla_obs(0, scope)
microns = 3e8/(fctr*1e6)*1e6
app_rarad, app_decrad = s.sla_map(ra*DEGTORAD,dec*DEGTORAD,0.0,0.0,0.0,0.0,2000.0,MJD)
az, za, hob, rob, dob = s.sla_aop(app_rarad,app_decrad,MJD,
0.0,-lon,lat,hgt,0.0,0.0,temp,atm,humid,microns,0.0065)
az = s.sla_dranrm(az)
return az*RADTODEG, za*RADTODEG
def azza_to_radec(az,
za,
MJD,
fctr=350.0,
atm=1010.0,
temp=283.0,
humid=0.5,
scope='GBT'):
"""
azza_to_radec(az, za, MJD):
Return RA and DEC (J2000 in deg) from AZ and ZA (in deg) at MJD. Keyword params
are fctr=350.0, atm=1010.0, temp=283.0, humid=0.5, scope='GBT'.
"""
scope, x, lon, lat, hgt = s.sla_obs(0, scope)
microns = 3e8 / (fctr * 1e6) * 1e6
app_rarad, app_decrad = s.sla_oap('a', az * DEGTORAD, za * DEGTORAD, MJD,
0.0, -lon, lat, hgt, 0.0, 0.0, temp, atm,
humid, microns, 0.0065)
ra2000, dec2000 = s.sla_amp(app_rarad, app_decrad, MJD, 2000.0)
return ra2000 * RADTODEG, dec2000 * RADTODEG
def radec_to_azza(ra,
dec,
MJD,
fctr=350.0,
atm=1010.0,
temp=283.0,
humid=0.5,
scope='GBT'):
"""
redec_to_azza(ra, dec, MJD):
Return AZ and ZA (in deg) from RA and DEC (J2000 in deg) at MJD. Keyword params
are fctr=350.0, atm=1010.0, temp=283.0, humid=0.5, scope='GBT'.
"""
scope, x, lon, lat, hgt = s.sla_obs(0, scope)
microns = 3e8 / (fctr * 1e6) * 1e6
app_rarad, app_decrad = s.sla_map(ra * DEGTORAD, dec * DEGTORAD, 0.0, 0.0,
0.0, 0.0, 2000.0, MJD)
az, za, hob, rob, dob = s.sla_aop(app_rarad, app_decrad, MJD, 0.0, -lon,
lat, hgt, 0.0, 0.0, temp, atm, humid,
microns, 0.0065)
az = s.sla_dranrm(az)
return az * RADTODEG, za * RADTODEG
def rvcorr(hdr):
"""Calculate helio- and geo-centric corrections to radial velocities
The result should be subtracted from the observed (topocentric)
velocities in order to give velocities in the heliocentric frame.
"""
# The following page was very helpful in pointing to the relevant
# SLALIB routines and how to use them
# http://star-www.rl.ac.uk/docs/sun67.htx/node230.html
# Object coordinates
ra = coord.RA(hdr["RA"], U.hour)
dec = coord.Dec(hdr["DEC"], U.degree)
# Modified Julian Date
jdate = float(hdr["MJD"])
# Sidereal time
st = coord.Angle((hdr["ST"]), U.hour)
# line-of-sight unit vector to astronomical object
k_los = sla_dcs2c(ra.radians, dec.radians)
# Velocity and position of earth in barycentric and heliocentric frames
# Units are AU and AU/s
vel_bary, pos_bary, vel_hel, pos_hel = sla_evp(jdate, 2000.0)
# Radial velocity correction (km/s) due to helio-geocentric transformation
# Positive when earth is moving away from object
vcorr_hel = U.AU.to(U.km, -np.dot(vel_hel, k_los))
# Long/lat/altitude of observatory (radians, radians, meters)
obs_id, obs_name, obs_long, obs_lat, obs_height = sla_obs(0, "KECK1")
# Radial velocity correction (km/s) due to geo-topocentric transformation
# Positive when observatory is moving away from object
vcorr_geo = sla_rverot(obs_lat, ra.radians, dec.radians, st.radians)
return vcorr_hel + vcorr_geo
def translate_header(fits_file, skip, output_subints):
fits_hdr = fits_file['PRIMARY'].header
subint_hdr = fits_file['SUBINT'].header
fil_header = dict.fromkeys(fil_header_keys, None)
if fits_hdr['TELESCOP'] in telescope_ids:
fil_header["telescope_id"] = telescope_ids[fits_hdr['TELESCOP']]
else:
fil_header["telescope_id"] = -1
if fits_hdr['BACKEND'] in machine_ids:
fil_header["machine_id"] = machine_ids[fits_hdr['BACKEND']]
else:
fil_header["machine_id"] = -1
fil_header["data_type"] = 1 # filterbank
# Get filename in a way that is safe for old versions of pyfits
# (i.e. using private attribute)
#Let's get the center of our intended output file.
#Right now I'm assuming we're in search mode and that we'll take
#The subint offset from the first file and add skip +
#output_subints / 2 subints to get the position of the telescope.
time_subint = subint_hdr['TBIN'] * subint_hdr['NSBLK']
time_offset = subint_hdr['NSUBOFFS'] * time_subint + \
skip * time_subint
#Let's set some variables that we'll use to update our position
#via pyslalib
type = "A" #We need this for SLA
dtmp = 0.0 #Delta UT
atm = 1010.0 #Local atmospheric pressure in mB
temp = 283.0 #Local temperature in DegK
humid = 0.5 #Local relative humidity in range 0.0-1.0
tlr = 0.0065 #Tropospheric lapse rate (DegL/meter)
eq = 2000.0 #Julian epoch of mean place
microns = 3e8 / fits_hdr['OBSFREQ'] * 1e6 * 1e6
az = radians(fits_file['SUBINT'].data[0]['TEL_AZ']) #azimuth
za = radians(fits_file['SUBINT'].data[0]['TEL_ZEN']) #zenith
tstart = fits_hdr['STT_IMJD'] + \
fits_hdr['STT_SMJD']/86400.0 + \
fits_hdr['STT_OFFS']/86400.0 + \
time_offset/86400.0 #tstart of new file
#Now let's get the MJD of the center of the new file
#so that we can update the RA/DEC for the new file
MJD = tstart + (time_subint * output_subints / 2) / 86400.0
#Ok, I think we're set to update our position. Let's use slalib
#to get the position of the telescope
telecope,telescope_name,tel_lon,tel_lat,tel_hgt = \
sla.sla_obs(0,fits_hdr['TELESCOP'])
#Now we have tel_lon,tel_lat and tel_ght. We need to flip the lon
tel_lon = -tel_lon
#Let's get the geocentric apparent RA and DEC
rap,dap = sla.sla_oap(type,az,za,MJD,dtmp,tel_lon,tel_lat,tel_hgt,\
dtmp,dtmp,temp,atm,humid,microns,tlr)
#OK, for reals we are almost there Let's convert to FK5 (mean place)
rmn, dmn = sla.sla_amp(rap, dap, MJD, eq)
hours, hmin, hsec = presto.hours2hms(degrees(rmn) / 15.0)
deg, dmin, dsec = presto.deg2dms(degrees(dmn) / 15.0)
fil_header["src_raj"] = float(hours * 10000.0 + hmin * 100.0 + hsec)
fil_header["src_dej"] = float(deg * 10000.0 + dmin * 100.0 + dsec)
fn = fits_file._HDUList__file.name
fil_header["rawdatafile"] = os.path.basename(fn)
fil_header["source_name"] = fits_hdr['SRC_NAME']
fil_header["barycentric"] = 0 # always not barycentered?
fil_header["pulsarcentric"] = 0 # whats pulsarcentric?
fil_header["az_start"] = fits_file['SUBINT'].data[0]['TEL_AZ']
fil_header["za_start"] = fits_file['SUBINT'].data[0]['TEL_ZEN']
# fil_header["src_raj"] = float(fits_hdr['RA'].replace(':',''))
# fil_header["src_dej"] = float(fits_hdr['DEC'].replace(':',''))
fil_header["tstart"] = fits_hdr['STT_IMJD'] + \
fits_hdr['STT_SMJD']/86400.0 + \
fits_hdr['STT_OFFS']/86400.0 + \
time_offset/86400.0
fil_header["tsamp"] = subint_hdr['TBIN']
fil_header["nbits"] = None # set by user. Input should always be 4-bit.
# first channel (fch1) in sigproc is the highest freq
# foff is negative to signify this
fil_header["fch1"] = fits_hdr['OBSFREQ'] + \
np.abs(fits_hdr['OBSBW'])/2.0 - \
np.abs(subint_hdr['CHAN_BW'])/2.0
fil_header["foff"] = -1.0 * np.abs(subint_hdr['CHAN_BW'])
fil_header["nchans"] = subint_hdr['NCHAN']
fil_header["nifs"] = subint_hdr['NPOL']
return fil_header
def translate_header(fits_file,skip,output_subints):
fits_hdr = fits_file['PRIMARY'].header
subint_hdr = fits_file['SUBINT'].header
fil_header = dict.fromkeys(fil_header_keys,None)
if fits_hdr['TELESCOP'] in telescope_ids:
fil_header["telescope_id"] = telescope_ids[fits_hdr['TELESCOP']]
else:
fil_header["telescope_id"] = -1
if fits_hdr['BACKEND'] in machine_ids:
fil_header["machine_id"] = machine_ids[fits_hdr['BACKEND']]
else:
fil_header["machine_id"] = -1
fil_header["data_type"] = 1 # filterbank
# Get filename in a way that is safe for old versions of pyfits
# (i.e. using private attribute)
#Let's get the center of our intended output file.
#Right now I'm assuming we're in search mode and that we'll take
#The subint offset from the first file and add skip +
#output_subints / 2 subints to get the position of the telescope.
time_subint = subint_hdr['TBIN']*subint_hdr['NSBLK']
time_offset = subint_hdr['NSUBOFFS'] * time_subint + \
skip * time_subint
#Let's set some variables that we'll use to update our position
#via pyslalib
type = "A" #We need this for SLA
dtmp = 0.0 #Delta UT
atm = 1010.0 #Local atmospheric pressure in mB
temp = 283.0 #Local temperature in DegK
humid = 0.5 #Local relative humidity in range 0.0-1.0
tlr = 0.0065 #Tropospheric lapse rate (DegL/meter)
eq = 2000.0 #Julian epoch of mean place
microns = 3e8 / fits_hdr['OBSFREQ']*1e6*1e6
az = radians(fits_file['SUBINT'].data[0]['TEL_AZ']) #azimuth
za = radians(fits_file['SUBINT'].data[0]['TEL_ZEN']) #zenith
tstart = fits_hdr['STT_IMJD'] + \
fits_hdr['STT_SMJD']/86400.0 + \
fits_hdr['STT_OFFS']/86400.0 + \
time_offset/86400.0 #tstart of new file
#Now let's get the MJD of the center of the new file
#so that we can update the RA/DEC for the new file
MJD = tstart + (time_subint * output_subints / 2)/86400.0
#Ok, I think we're set to update our position. Let's use slalib
#to get the position of the telescope
telecope,telescope_name,tel_lon,tel_lat,tel_hgt = \
sla.sla_obs(0,fits_hdr['TELESCOP'])
#Now we have tel_lon,tel_lat and tel_ght. We need to flip the lon
tel_lon = -tel_lon
#Let's get the geocentric apparent RA and DEC
rap,dap = sla.sla_oap(type,az,za,MJD,dtmp,tel_lon,tel_lat,tel_hgt,\
dtmp,dtmp,temp,atm,humid,microns,tlr)
#OK, for reals we are almost there Let's convert to FK5 (mean place)
rmn,dmn = sla.sla_amp(rap,dap,MJD,eq)
hours,hmin,hsec = presto.hours2hms(degrees(rmn)/15.0)
deg,dmin,dsec = presto.deg2dms(degrees(dmn)/15.0)
fil_header["src_raj"] = float(hours*10000.0 + hmin*100.0 + hsec)
fil_header["src_dej"] = float(deg*10000.0 + dmin*100.0 + dsec)
fn = fits_file._HDUList__file.name
fil_header["rawdatafile"] = os.path.basename(fn)
fil_header["source_name"] = fits_hdr['SRC_NAME']
fil_header["barycentric"] = 0 # always not barycentered?
fil_header["pulsarcentric"] = 0 # whats pulsarcentric?
fil_header["az_start"] = fits_file['SUBINT'].data[0]['TEL_AZ']
fil_header["za_start"] = fits_file['SUBINT'].data[0]['TEL_ZEN']
# fil_header["src_raj"] = float(fits_hdr['RA'].replace(':',''))
# fil_header["src_dej"] = float(fits_hdr['DEC'].replace(':',''))
fil_header["tstart"] = fits_hdr['STT_IMJD'] + \
fits_hdr['STT_SMJD']/86400.0 + \
fits_hdr['STT_OFFS']/86400.0 + \
time_offset/86400.0
fil_header["tsamp"] = subint_hdr['TBIN']
fil_header["nbits"] = None # set by user. Input should always be 4-bit.
# first channel (fch1) in sigproc is the highest freq
# foff is negative to signify this
fil_header["fch1"] = fits_hdr['OBSFREQ'] + \
np.abs(fits_hdr['OBSBW'])/2.0 - \
np.abs(subint_hdr['CHAN_BW'])/2.0
fil_header["foff"] = -1.0*np.abs(subint_hdr['CHAN_BW'])
fil_header["nchans"] = subint_hdr['NCHAN']
fil_header["nifs"] = subint_hdr['NPOL']
return fil_header
