gammapy.utils.coordinates.D_SUN_TO_GALACTIC_CENTER = <Quantity 8.5 kpc>#

A Quantity represents a number with some associated unit.

See also: https://docs.astropy.org/en/stable/units/quantity.html

valuenumber, ndarray, Quantity (sequence), or str

The numerical value of this quantity in the units given by unit. If a Quantity or sequence of them (or any other valid object with a unit attribute), creates a new Quantity object, converting to unit units as needed. If a string, it is converted to a number or Quantity, depending on whether a unit is present.


An object that represents the unit associated with the input value. Must be an UnitBase object or a string parseable by the units package.

dtype~numpy.dtype, optional

The dtype of the resulting Numpy array or scalar that will hold the value. If not provided, it is determined from the input, except that any integer and (non-Quantity) object inputs are converted to float by default. If None, the normal numpy.dtype introspection is used, e.g. preventing upcasting of integers.

copybool, optional

If True (default), then the value is copied. Otherwise, a copy will only be made if __array__ returns a copy, if value is a nested sequence, or if a copy is needed to satisfy an explicitly given dtype. (The False option is intended mostly for internal use, to speed up initialization where a copy is known to have been made. Use with care.)

order{‘C’, ‘F’, ‘A’}, optional

Specify the order of the array. As in array. This parameter is ignored if the input is a Quantity and copy=False.

subokbool, optional

If False (default), the returned array will be forced to be a Quantity. Otherwise, Quantity subclasses will be passed through, or a subclass appropriate for the unit will be used (such as Dex for u.dex(u.AA)).

ndminint, optional

Specifies the minimum number of dimensions that the resulting array should have. Ones will be pre-pended to the shape as needed to meet this requirement. This parameter is ignored if the input is a Quantity and copy=False.


If the value provided is not a Python numeric type.


If the unit provided is not either a Unit object or a parseable string unit.


Quantities can also be created by multiplying a number or array with a Unit. See https://docs.astropy.org/en/latest/units/

Unless the dtype argument is explicitly specified, integer or (non-Quantity) object inputs are converted to float by default.