Define a quantity from scalars and units:

>>> from astropy import units as u

>>> 15.1 * u.m / u.s

<Quantity 15.1 m / s>

Convert a distance:

>>> (1.15e13 * u.km).to(u.pc)

<Quantity 0.372689618289 pc>

Make use of the unit equivalencies:

>>> e = 130. * u.eV

>>> e.to(u.Angstrom, equivalencies=u.spectral())

<Quantity 95.37245609234003 Angstrom>

Combine quantities:

>>> x = 1.4e11 * u.km / (0.7 * u.Myr)

>>> x

<Quantity 2e+11 km / Myr>

Convert to SI and CGS units:

>>> x.si

<Quantity 6.33761756281 m / s>

>>> x.cgs

<Quantity 633.761756281 cm / s>

Use units with NumPy arrays

>>> import numpy as np

>>> d = np.array([1, 2, 3, 4]) * u.m

>>> d.to(u.cm)

<Quantity [ 100. 200. 300. 400.] cm>

>>> d * 1. / 50. * u.s ** -1

<Quantity [ 2. 4. 6. 8.] cm / s>