# Calculating the redshift drift

I am trying to calculate the redshift drift where its written as

$$\frac{dz}{dt} = (1+z)H_0 - H \tag{1}$$

We also know that $$1+z = a(t_o) / a(t_e) \tag{2}$$

and $$H_0 = \frac{\dot{a}(t_0)}{a(t_0)}$$

$$H = \frac{\dot{a}(t_e)}{a(t_e)}$$

• Related question: physics.stackexchange.com/q/400386 Sep 30, 2020 at 12:45
• Layla, can you specify your problem? If you know the scale factors then the redshift is given by your equation (2).
– psm
Sep 30, 2020 at 15:13
• @psm What information do you need ? Oct 3, 2020 at 18:29