Angle Units

class coord.AngleUnit(value)

A class for defining angular units used by Angle objects.

Initialization:

An AngleUnit takes a single argument for initialization, a float that specifies the size of the desired angular unit in radians. For example:

coord.AngleUnit.__init__()

>>> gradian = AngleUnit(2. * math.pi / 400.)
>>> print(gradian)
coord.AngleUnit(0.015707963267948967)

Built-in units:

There are five built-in AngleUnits which are always available for use:

coord.radians:

coord.AngleUnit(1.)

coord.degrees:

coord.AngleUnit(pi / 180.)

coord.hours:

coord.AngleUnit(pi / 12.)

coord.arcmin:

coord.AngleUnit(pi / 180. / 60.)

coord.arcsec:

coord.AngleUnit(pi / 180. / 3600.)

Attribute:

An AngleUnit as the following (read-only) attribute:

value:

The measure of the unit in radians.

__init__(value)

Parameters:

value – The measure of the unit in radians.

property value

A read-only attribute giving the measure of the AngleUnit in radians.

static from_name(unit)

Convert a string into the corresponding AngleUnit.

Only the start of the string is checked, so for instance ‘radian’ or ‘radians’ is equivalent to ‘rad’.

Valid options are:

rad:

AngleUnit(1.)

deg:

AngleUnit(pi / 180.)

hour or hr:

AngleUnit(pi / 12.)

arcmin:

AngleUnit(pi / 180. / 60.)

arcsec:

AngleUnit(pi / 180. / 3600.)

Note: these valid names are listed in AngleUnit.valid_names.

Parameters:

unit – The string name of the unit to return

Returns:

an AngleUnit