def transform_celestial(coords, systems):
lons, lats = np.radians(coords['lon']), np.radians(coords['lat'])
out = Table()
out['lon'] = np.zeros(len(coords), dtype='float64')
out['lat'] = np.zeros(len(coords), dtype='float64')
for ii, (lon, lat) in enumerate(zip(lons, lats)):
# First convert to FK5 J2000 in all cases
if systems['in'] == 'fk4':
lon, lat = slalib.sla_fk45z(lon, lat, 2000.0012775136652)
elif systems['in'] == 'icrs':
lon, lat = slalib.sla_hfk5z(lon, lat, 2000)[:2]
elif systems['in'] == 'galactic':
lon, lat = slalib.sla_galeq(lon, lat)
elif systems['in'] == 'ecliptic':
lon, lat = slalib.sla_ecleq(lon, lat, 51544)
# Now convert from FK5 J2000 to out system
if systems['out'] == 'fk4':
# FK5 -> FK4 at BEPOCH 2000 assuming no proper motion or parallax
lon, lat = slalib.sla_fk54z(lon, lat, 2000.0012775136652)[:2]
elif systems['out'] == 'icrs':
# FK5 -> Hipparcos (i.e. ICRF, which is as close as SLALIB
# gets to ICRS) at epoch 2000 and with no proper motion
lon, lat = slalib.sla_fk5hz(lon, lat, 2000)
elif systems['out'] == 'galactic':
# FK5 -> Galactic
lon, lat = slalib.sla_eqgal(lon, lat)
elif systems['out'] == 'ecliptic':
# FK5 -> Ecliptic at TDB (MJD) 51544 (i.e. J2000)
lon, lat = slalib.sla_eqecl(lon, lat, 51544)
out[ii]['lon'] = np.degrees(lon)
out[ii]['lat'] = np.degrees(lat)
return out
def transform_celestial(coords, systems):
lons, lats = np.radians(coords['lon']), np.radians(coords['lat'])
out = Table()
out['lon'] = np.zeros(len(coords), dtype='float64')
out['lat'] = np.zeros(len(coords), dtype='float64')
for ii, (lon, lat) in enumerate(zip(lons, lats)):
# First convert to FK5 J2000 in all cases
if systems['in'] == 'fk4':
lon, lat = slalib.sla_fk45z(lon, lat, 2000.0012775136652)
elif systems['in'] == 'icrs':
lon, lat = slalib.sla_hfk5z(lon, lat, 2000)[:2]
elif systems['in'] == 'galactic':
lon, lat = slalib.sla_galeq(lon, lat)
elif systems['in'] == 'ecliptic':
lon, lat = slalib.sla_ecleq(lon, lat, 51544)
# Now convert from FK5 J2000 to out system
if systems['out'] == 'fk4':
# FK5 -> FK4 at BEPOCH 2000 assuming no proper motion or parallax
lon, lat = slalib.sla_fk54z(lon, lat, 2000.0012775136652)[:2]
elif systems['out'] == 'icrs':
# FK5 -> Hipparcos (i.e. ICRF, which is as close as SLALIB
# gets to ICRS) at epoch 2000 and with no proper motion
lon, lat = slalib.sla_fk5hz(lon, lat, 2000)
elif systems['out'] == 'galactic':
# FK5 -> Galactic
lon, lat = slalib.sla_eqgal(lon, lat)
elif systems['out'] == 'ecliptic':
# FK5 -> Ecliptic at TDB (MJD) 51544 (i.e. J2000)
lon, lat = slalib.sla_eqecl(lon, lat, 51544)
out[ii]['lon'] = np.degrees(lon)
out[ii]['lat'] = np.degrees(lat)
return out
def convert(coords, systems):
if not set(systems.values()).issubset(SUPPORTED_SYSTEMS):
return None
lons, lats = np.radians(coords['lon']), np.radians(coords['lat'])
for ii, (lon, lat) in enumerate(zip(lons, lats)):
# First convert to FK5 J2000 in all cases
if systems['in'] == 'fk4':
lon, lat = slalib.sla_fk45z(lon, lat, 2000.0012775136652)
elif systems['in'] == 'icrs':
lon, lat = slalib.sla_hfk5z(lon, lat, 2000)[:2]
elif systems['in'] == 'galactic':
lon, lat = slalib.sla_galeq(lon, lat)
elif systems['in'] == 'ecliptic':
lon, lat = slalib.sla_ecleq(lon, lat, 51544)
# Now convert from FK5 J2000 to out system
if systems['out'] == 'fk4':
# FK5 -> FK4 at BEPOCH 2000 assuming no proper motion or parallax
lon, lat = slalib.sla_fk54z (lon, lat, 2000.0012775136652)[:2]
elif systems['out'] == 'icrs':
# FK5 -> Hipparcos (i.e. ICRF, which is as close as SLALIB
# gets to ICRS) at epoch 2000 and with no proper motion
lon, lat = slalib.sla_fk5hz(lon, lat, 2000)
elif systems['out'] == 'galactic':
# FK5 -> Galactic
lon, lat = slalib.sla_eqgal(lon, lat)
elif systems['out'] == 'ecliptic':
# FK5 -> Ecliptic at TDB (MJD) 51544 (i.e. J2000)
lon, lat = slalib.sla_eqecl(lon, lat, 51544)
lons[ii], lats[ii] = lon, lat
return dict(lon=np.degrees(lons), lat=np.degrees(lats))
