def _calculate_pos_crs(self, source):
"""Calculate position for a source
Args:
source (String): Key saying which source to calculate position for.
Returns:
Array: Positions, one 2-vector
"""
ga = 0.0058 * Unit.mas2rad # Aberration constant (mas/yr)
mjd_2015 = 57023.0 # # Reference epoch of aberration model
# Galactic center
gc = Direction(ra=Unit.hms_to_rad(17, 45, 40.04),
dec=Unit.dms_to_rad(-29, 0, 28.1))
# Radio source
src = Direction(ra=self.data[source]["ra"],
dec=self.data[source]["dec"])
# Compute correction
dra = ga * gc.unit_vector @ src.dsrc_dra
ddec = ga * gc.unit_vector @ src.dsrc_ddec
dt = (self.time.mean.mjd - mjd_2015) * Unit.day2julian_year
ra = src.right_ascension + dra * dt
dec = src.declination + ddec * dt
return np.squeeze(Direction(ra=ra, dec=dec, time=self.time))
def _calculate_pos_crs(self, source):
"""Calculate position for a source
Args:
source (String): Key saying which source to calculate position for.
Returns:
Array: Positions, one 2-vector
"""
ga = 0.0058 * Unit.mas2rad # Aberration constant (mas/yr)
mjd_2015 = 57023.0 # # Reference epoch of aberration model
# Galactic center
gc_ra = Unit.hms_to_rad(17, 45, 40.04)
gc_dec = Unit.dms_to_rad(-29, 0, 28.1)
gc = radec2unitvector(gc_ra, gc_dec)
source_info = self.data[source]
# Compute correction
dra = ga * gc @ dsrc_dra(source_info["ra"], source_info["dec"])
ddec = ga * gc @ dsrc_ddec(source_info["ra"], source_info["dec"])
dt = (self.time.mean.mjd - mjd_2015) * Unit.day2julian_year
return np.array(
[source_info["ra"] + dra * dt, source_info["dec"] + ddec * dt])
def _convert_dms2rad(self, field: bytes) -> float:
"""Convert DMS (degrees, minutes, seconds) to radians
Args:
field: Original field with degrees, minutes, seconds separated by whitespace.
Returns:
Field converted to radians.
"""
degrees, minutes, seconds = [float(f) for f in field.split()]
return Unit.dms_to_rad(degrees, minutes, seconds)
def parse_radio_source(self, line, _):
"""Read station position
Reads the station position from the NGS file.
Args:
line: Input data from NGS file
"""
src_name = line["name"]
self.data[src_name] = dict()
self.data[src_name]["ra"] = Unit.hms_to_rad(float(line["ra_hrs"]),
int(line["ra_mins"]),
float(line["ra_secs"]))
self.data[src_name]["dec"] = Unit.dms_to_rad(
float(line["dec_degs"].replace(" ", "")), int(line["dec_mins"]),
float(line["dec_secs"]))
def structure_data(self):
ra = Unit.hms_to_rad(self._array["ra_h"], self._array["ra_m"],
self._array["ra_s"])
dec = Unit.dms_to_rad(self._array["dec_deg"], self._array["dec_m"],
self._array["dec_s"])
src_type = dict(vcs=False, non_vcs=True, undefined=False)
self.data = {
src["iers_name"]: dict(icrf_name=src["icrf_name"],
defining=src["defining"],
special=src["special"],
ra=ra[i],
dec=dec[i],
**src_type)
for i, src in enumerate(self._array)
}
