doppler_radio#

astropy.units.equivalencies.doppler_radio(rest)[源代码]#

返回速率的无线电约定的等效对。

速度和频率之间关系的无线电约定为：

\(V = c \frac{f_0 - f}{f_0} ; f(V) = f_0 ( 1 - V/c )\)

参数:

rest ： Quantity数量: 由标准光谱当量（波长、能量、频率、波数）支持的任何数量。

工具书类

NRAO site defining the conventions

实例

>>> import astropy.units as u
>>> CO_restfreq = 115.27120*u.GHz  # rest frequency of 12 CO 1-0 in GHz
>>> radio_CO_equiv = u.doppler_radio(CO_restfreq)
>>> measured_freq = 115.2832*u.GHz
>>> radio_velocity = measured_freq.to(u.km/u.s, equivalencies=radio_CO_equiv)
>>> radio_velocity  
<Quantity -31.209092088877583 km / s>