class ArbitraryPoleFrame(coord.BaseCoordinateFrame):
default_representation = coord.SphericalRepresentation
default_differential = coord.SphericalCosLatDifferential
frame_specific_representation_info = {
coord.SphericalRepresentation: [
coord.RepresentationMapping('lon', 'phi1'),
coord.RepresentationMapping('lat', 'phi2'),
coord.RepresentationMapping('distance', 'distance')
],
coord.SphericalCosLatDifferential: [
coord.RepresentationMapping('d_lon_coslat', 'pm_phi1_cosphi2'),
coord.RepresentationMapping('d_lat', 'pm_phi2'),
coord.RepresentationMapping('d_distance', 'radial_velocity')
],
coord.SphericalDifferential: [
coord.RepresentationMapping('d_lon', 'pm_phi1'),
coord.RepresentationMapping('d_lat', 'pm_phi2'),
coord.RepresentationMapping('d_distance', 'radial_velocity')
]
}
pole = coord.CoordinateAttribute(frame=coord.ICRS)
roll = coord.QuantityAttribute(default=0 * u.degree)
class SDSSMuNu(ac.BaseCoordinateFrame):
"""SDSS Great Circle Coordinates
Attributes
----------
stripe
SDSS `Stripe Number`_ .
node
Node of the great circle with respect to the celestial equator.
In SDSS, this is almost always RA = 95.0 degrees.
incl
Inclination of the great circle with respect to the celestial
equator.
phi
Counter-clockwise position angle w.r.t. north for an arc
in the +nu direction.
Parameters
----------
mu : :class:`~astropy.coordinates.Angle`
Angle corresponding to longitude measured along a stripe.
nu : :class:`~astropy.coordinates.Angle`
Angle corresponding to latitude measured perpendicular to a stripe.
Notes
-----
https://www.sdss.org/dr14/algorithms/surveycoords/
.. _`Stripe Number`: https://www.sdss.org/dr14/help/glossary/#stripe
"""
default_representation = ac.SphericalRepresentation
frame_specific_representation_info = {
'spherical': [
ac.RepresentationMapping(reprname='lon',
framename='mu',
defaultunit=u.deg),
ac.RepresentationMapping(reprname='lat',
framename='nu',
defaultunit=u.deg)
]
}
frame_specific_representation_info['unitspherical'] = (
frame_specific_representation_info['spherical'])
stripe = ac.Attribute(default=0)
node = ac.QuantityAttribute(default=ac.Angle(95.0, unit=u.deg), unit=u.deg)
# phi = ac.QuantityFrameAttribute(default=None, unit=u.deg)
@property
def incl(self):
return ac.Angle(stripe_to_incl(self.stripe), unit=u.deg)
class LMCtoGal(coord.BaseCoordinateFrame):
"""
A cartesian coordinate system that has the X-Z plane such that it crosses
through Galactic Center, the LMC, and the Southern Galactic Pole.
The z-axis is perpendicular to the Galactic plane, with positive Z pointed
towards the Southern Galactic Pole.
Requires knowing the coordinates and distance to the LMC, as well as a distance
to galactic center of the Sun's position in the Galaxy
Will default to using the same values used in Bland-Hawthorn et al. (2019)
Attributes
----------
LMC_coord: `astropy.coordinates.SkyCoord`, optional, must be keyword
Coordinate of LMC, including distance from sun
galcen_distance: `astropy.units.Quantity`, optional, must be keyword
distance of Sun to Galactic Center
Parameters
----------
x: `astropy.units.Quantity`, optional, must be keyword
The x coordinate in the LMCtoGal coordinate system
y: `astropy.units.Quantity`, optional, must be keyword
The y coordinate in the LMCtoGal coordinate system
z: `astropy.units.Quantity`, optional, must be keyword
The z coordinate in the LMCtoGal coordinate system
"""
default_representation = coord.CartesianRepresentation
# Specify frame attributes required to fully specify the frame
galcen_distance = coord.QuantityAttribute(default=8.122 * u.kpc,
unit=u.kpc)
LMC_coord = coord.CoordinateAttribute(coord.Galactic,
default=SkyCoord(
ra=80.89416667 * u.deg,
dec=-69.75611111 * u.deg,
distance=50.0 * u.kpc,
frame="icrs"))