Angle¶

class astropy.coordinates.Angle(angle, unit=None, dtype=<class 'numpy.inexact'>, copy=True, **kwargs)[source]¶

Bases: SpecificTypeQuantity

One or more angular value(s) with units equivalent to radians or degrees.

An angle can be specified either as an array, scalar, tuple (see below), string, Quantity or another Angle.

The input parser is flexible and supports a variety of formats. The examples below illustrate common ways of initializing an Angle object. First some imports:

>>> from astropy.coordinates import Angle
>>> from astropy import units as u

The angle values can now be provided:

>>> Angle('10.2345d')
<Angle 10.2345 deg>
>>> Angle(['10.2345d', '-20d'])
<Angle [ 10.2345, -20.    ] deg>
>>> Angle('1:2:30.43 degrees')
<Angle 1.04178611 deg>
>>> Angle('1 2 0 hours')
<Angle 1.03333333 hourangle>
>>> Angle(np.arange(1, 8), unit=u.deg)
<Angle [1., 2., 3., 4., 5., 6., 7.] deg>
>>> Angle('1°2′3″')
<Angle 1.03416667 deg>
>>> Angle('1°2′3″N')
<Angle 1.03416667 deg>
>>> Angle('1d2m3.4s')
<Angle 1.03427778 deg>
>>> Angle('1d2m3.4sS')
<Angle -1.03427778 deg>
>>> Angle('-1h2m3s')
<Angle -1.03416667 hourangle>
>>> Angle('-1h2m3sE')
<Angle -1.03416667 hourangle>
>>> Angle('-1h2.5m')
<Angle -1.04166667 hourangle>
>>> Angle('-1h2.5mW')
<Angle 1.04166667 hourangle>
>>> Angle('-1:2.5', unit=u.deg)
<Angle -1.04166667 deg>
>>> Angle(10.2345 * u.deg)
<Angle 10.2345 deg>
>>> Angle(Angle(10.2345 * u.deg))
<Angle 10.2345 deg>

Parameters:

anglearray, scalar, Quantity, Angle

The angle value. If a tuple, will be interpreted as (h, m, s) or (d, m, s) depending on unit. If a string, it will be interpreted following the rules described above.

If angle is a sequence or array of strings, the resulting values will be in the given unit, or if None is provided, the unit will be taken from the first given value.

unitastropy:unit-like, optional

The unit of the value specified for the angle. This may be any string that Unit understands, but it is better to give an actual unit object. Must be an angular unit.

dtypedtype, optional

See Quantity.

copybool, optional

See Quantity.

Raises:

UnitsError: If a unit is not provided or it is not an angular unit.

Attributes Summary

`dms`	The angle's value in degrees, as a `(d, m, s)` named tuple.
`hms`	The angle's value in hours, as a named tuple with `(h, m, s)` members.
`hour`	The angle's value in hours (read-only property).
`signed_dms`	The angle's value in degrees, as a `(sign, d, m, s)` named tuple.

Methods Summary

`is_within_bounds`([lower, upper])	Check if all angle(s) satisfy `lower <= angle < upper`.
`to_string`([unit, decimal, sep, precision, ...])	A string representation of the angle.
`wrap_at`(wrap_angle[, inplace])	Wrap the `Angle` object at the given `wrap_angle`.

Attributes Documentation

dms¶: The angle’s value in degrees, as a (d, m, s) named tuple.

hms¶: The angle’s value in hours, as a named tuple with (h, m, s) members.

hour¶: The angle’s value in hours (read-only property).

signed_dms¶

The angle’s value in degrees, as a (sign, d, m, s) named tuple.

The d, m, s are thus always positive, and the sign of the angle is given by sign.

This is primarily intended for use with dms to generate string representations of coordinates that are correct for negative angles.

Methods Documentation

is_within_bounds(lower=None, upper=None)[source]¶

Check if all angle(s) satisfy lower <= angle < upper.

If lower is not specified (or None) then no lower bounds check is performed. Likewise upper can be left unspecified. For example:

>>> from astropy.coordinates import Angle
>>> import astropy.units as u
>>> a = Angle([-20, 150, 350] * u.deg)
>>> a.is_within_bounds('0d', '360d')
False
>>> a.is_within_bounds(None, '360d')
True
>>> a.is_within_bounds(-30 * u.deg, None)
True

Parameters:

lowerastropy:angle-like or None: Specifies lower bound for checking. This can be any object that can initialize an Angle object, e.g. '180d', 180 * u.deg, or Angle(180, unit=u.deg).
upperastropy:angle-like or None: Specifies upper bound for checking. This can be any object that can initialize an Angle object, e.g. '180d', 180 * u.deg, or Angle(180, unit=u.deg).

Returns:

is_within_boundsbool: True if all angles satisfy lower <= angle < upper

to_string(unit=None, decimal=False, sep='fromunit', precision=None, alwayssign=False, pad=False, fields=3, format=None)[source]¶

A string representation of the angle.

Parameters:

unitUnitBase, optional

Specifies the unit. Must be an angular unit. If not provided, the unit used to initialize the angle will be used.

decimalbool, optional

If False, the returned string will be in sexagesimal form if possible (for units of degrees or hourangle). If True, a decimal representation will be used. In that case, no unit will be appended if format is not explicitly given.

sepstr, optional

The separator between numbers in a sexagesimal representation. E.g., if it is ‘:’, the result is '12:41:11.1241'. Also accepts 2 or 3 separators. E.g., sep='hms' would give the result '12h41m11.1241s', or sep=’-:’ would yield '11-21:17.124'. Alternatively, the special string ‘fromunit’ means ‘dms’ if the unit is degrees, or ‘hms’ if the unit is hours.

precisionint, optional

The level of decimal precision. If decimal is True, this is the raw precision, otherwise it gives the precision of the last place of the sexagesimal representation (seconds). If None, or not provided, the number of decimal places is determined by the value, and will be between 0-8 decimal places as required.

alwayssignbool, optional

If True, include the sign no matter what. If False, only include the sign if it is negative.

padbool, optional

If True, include leading zeros when needed to ensure a fixed number of characters for sexagesimal representation.

fieldsint, optional

Specifies the number of fields to display when outputting sexagesimal notation. For example:

fields == 1: '5d'

fields == 2: '5d45m'

fields == 3: '5d45m32.5s'

By default, all fields are displayed.

formatstr, optional

The format of the result. If not provided, an unadorned string is returned. Supported values are:

‘latex’: Return a LaTeX-formatted string
‘latex_inline’: Return a LaTeX-formatted string which is the same as with format='latex' for Angle instances
‘unicode’: Return a string containing non-ASCII unicode characters, such as the degree symbol

Returns:

strreprstr or array: A string representation of the angle. If the angle is an array, this will be an array with a unicode dtype.

wrap_at(wrap_angle, inplace=False)[source]¶

Wrap the Angle object at the given wrap_angle.

This method forces all the angle values to be within a contiguous 360 degree range so that wrap_angle - 360d <= angle < wrap_angle. By default a new Angle object is returned, but if the inplace argument is True then the Angle object is wrapped in place and nothing is returned.

For instance:

>>> from astropy.coordinates import Angle
>>> import astropy.units as u
>>> a = Angle([-20.0, 150.0, 350.0] * u.deg)

>>> a.wrap_at(360 * u.deg).degree  # Wrap into range 0 to 360 degrees  
array([340., 150., 350.])

>>> a.wrap_at('180d', inplace=True)  # Wrap into range -180 to 180 degrees  
>>> a.degree  
array([-20., 150., -10.])

Parameters:

wrap_angleastropy:angle-like: Specifies a single value for the wrap angle. This can be any object that can initialize an Angle object, e.g. '180d', 180 * u.deg, or Angle(180, unit=u.deg).
inplacebool: If True then wrap the object in place instead of returning a new Angle

Returns:

outAngle or None: If inplace is False (default), return new Angle object with angles wrapped accordingly. Otherwise wrap in place and return None.

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Angle¶