<p>That's about right.  There are several motions of the axis of Earth's rotation. There is precession (with a period of 25772 yr), but there is also nutation. The nutation of the Earth adds a small wobble of 9.2 arcseconds and a period of 18.6 years. So at some point in the early 31st century there will be several times when polaris and Gamma Cep are the same distance from the pole.</p>
<p>Moreover, precession is a perturbed motion, and not perfectly constant, if you are measuring it at the highest accuracy. To predict this, you need a model for precession, and different models will give slightly different answers.</p>
<p>For what it's worth, using the model in Stellarium, I find that the two stars are the same distance from the pole in December 3157. Of course there are other stars that are closer, and Gam Cep doesn't become visibly closer than Polaris until several hundred years after that.</p>

CC BY-SA 4.0
2024-03-17T06:41:04.550Z
see https://www.youtube.com/watch?v=k4QdAdm6-js for more
James K
CC BY-SA 4.0
2024-03-17T08:16:01.247Z
Great Video with visualisation!
planetmaker
CC BY-SA 4.0
2024-03-17T06:34:42.860Z
2024-03-17T06:34:42.860Z
James K
<p>I tried googling but I couldn't get any exact year, just any time between 3000 and 3100 CE. I want to know the exact year the north pole becomes closer to Gamma Cephei than Polaris. Apparently Polaris needs to be within 0.5 degrees of the pole, and GC needs to be within 3 degrees.</p>

<time><positional-astronomy><mathematics><night-sky>
What year will Gamma Cephei become the North Star?
Papa Solen'ya
# What year will Gamma Cephei become the North Star?

(Asked by: username_0 on 2024-03-17)

I tried googling but I couldn't get any exact year, just any time between 3000 and 3100 CE. I want to know the exact year the north pole becomes closer to Gamma Cephei than Polaris. Apparently Polaris needs to be within 0.5 degrees of the pole, and GC needs to be within 3 degrees.

**Tags:** time, positional-astronomy, mathematics, night-sky


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## 1 answers

### Answer by username_1 on 2024-03-17. Score: 2

That's about right. There are several motions of the axis of Earth's rotation. There is precession (with a period of 25772 yr), but there is also nutation. The nutation of the Earth adds a small wobble of 9.2 arcseconds and a period of 18.6 years. So at some point in the early 31st century there will be several times when polaris and Gamma Cep are the same distance from the pole.

Moreover, precession is a perturbed motion, and not perfectly constant, if you are measuring it at the highest accuracy. To predict this, you need a model for precession, and different models will give slightly different answers.

For what it's worth, using the model in Stellarium, I find that the two stars are the same distance from the pole in December 3157. Of course there are other stars that are closer, and Gam Cep doesn't become visibly closer than Polaris until several hundred years after that.

> **Comments:**
> **username_1**: see https://www.youtube.com/watch?v=k4QdAdm6-js for more  
> **username_2**: Great Video with visualisation!  

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