FK5

class astropy.coordinates.builtin_systems.FK5(*args, **kwargs)

Bases: astropy.coordinates.coordsystems.SphericalCoordinatesBase

A coordinate in the FK5 system.

Parameters:

coordstr : str

A single string with the coordinates. Cannot be used with dec and ra nor x/y/z.

ra : Angle, float, int, str

This must be given with dec.

dec : Angle, float, int, str

This must be given with ra.

distance : Distance, optional

This may be given with dec and ra or coordstr and not x, y, or z. If not given, None (unit sphere) will be assumed.

x : number

The first cartesian coordinate. Must be given with y and z and not with ra or dec nor coordstr.

y : number

The second cartesian coordinate. Must be given with x and z and not with ra or dec nor coordstr.

z : number

The third cartesian coordinate. Must be given with x and y and not with ra or dec nor coordstr.

cartpoint : CartesianPoints

A cartesian point with the coordinates. Cannot be used with any other arguments.

unit :

The unit parameter’s interpretation depends on what other parameters are given:

• If ra and dec or coordstr are given:

  unit must be a length-2 sequence specifying the units of ra and dec, respectively. They can be either UnitBase objects or strings that will be converted using Unit. They can also be None to attempt to automatically interpret the units (see Angle for details.) If unit is just None, this will be interpreted the same as (None, None).

• If x, y, and z are given:

  unit must be a single unit with dimensions of length

equinox : Time, optional

The equinox for these coordinates. Defaults to J2000.

obstime : Time or None

The time of observation for this coordinate. If None, it will be taken to be the same as the equinox.

Alternatively, a single argument that is any kind of spherical coordinate :

can be provided, and will be converted to `FK5` and used as this :

coordinate. :

Attributes Summary

dec
equinox
obstime
ra

Methods Summary

precess_to(newequinox)

Precesses the coordinates from their current equinox to a new equinox and returns the resulting coordinate.

Attributes Documentation

dec

equinox

obstime

ra

Methods Documentation

precess_to(newequinox)

Precesses the coordinates from their current equinox to a new equinox and returns the resulting coordinate.

Parameters:

newequinox : Time

The equinox to precess these coordinates to.

Returns:

newcoord : FK5

The new coordinate