<p>No. The apparent magnitude of the sun is constant to within 0.2%  How long it has been that way is only speculation since measurements aren't available. 1000 years is a very short time period in the life cycle of a star. Its safe to say yes its been constant for 1,000 years. There is a small variation based on the 11 year sun spot cycle but this variation is reported at less than 0.1%. There is also a larger variation due to the difference in Earth-to-Sun distance caused by the earths elliptical orbit. This effect is about 7%. This is no due to the sun but rather due to the eccentricity of Earths orbit. There are also minor effects with a cycle time or much greater than 1,000 years. These also due to variations in Earths orbit.</p>

CC BY-SA 3.0
2017-06-19T20:33:27.337Z
Don't discount the variation due to Earth's orbit eccentricity.
John Dvorak
CC BY-SA 3.0
2017-06-19T20:39:45.010Z
@Jan Dvorak. Absolutely correct.  I assumed questioner was looking for a variation due to the sun itself.  A bad assumption on my part. I will update my answer after I determine difference.
Natsfan
CC BY-SA 3.0
2017-06-20T06:39:26.897Z
Could you add how the brightness of the Sun 1000 years ago is known?
ProfRob
CC BY-SA 3.0
2017-06-20T11:09:52.007Z
I stated it was only speculation really.
Natsfan
CC BY-SA 3.0
2017-06-19T20:18:55.350Z
2017-06-19T21:20:13.883Z
2017-06-19T21:20:13.883Z
Natsfan
<p>Did the apparent magnitude of the Sun change in the past 1000 years or so? If so, for what reasons?</p>

CC BY-SA 3.0
2017-06-19T20:38:15.690Z
@Jan Dvorak. Absolutely correct.  I assumed questioner was looking for a variation due to the sun itself.  A bad assumption on my part. I will update my answer after I determine difference.
Natsfan
<the-sun><apparent-magnitude>
How much has the apparent magnitude of the Sun changed?
JobHunter69
# How much has the apparent magnitude of the Sun changed?

(Asked by: username_0 on 2017-06-19)

Did the apparent magnitude of the Sun change in the past 1000 years or so? If so, for what reasons?

**Tags:** the-sun, apparent-magnitude

> **Comments:**
> **username_1**: @Jan Dvorak. Absolutely correct.  I assumed questioner was looking for a variation due to the sun itself.  A bad assumption on my part. I will update my answer after I determine difference.  

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## 1 answers

### Answer by username_1 on 2017-06-19. Score: 2 | Accepted answer

No. The apparent magnitude of the sun is constant to within 0.2% How long it has been that way is only speculation since measurements aren't available. 1000 years is a very short time period in the life cycle of a star. Its safe to say yes its been constant for 1,000 years. There is a small variation based on the 11 year sun spot cycle but this variation is reported at less than 0.1%. There is also a larger variation due to the difference in Earth-to-Sun distance caused by the earths elliptical orbit. This effect is about 7%. This is no due to the sun but rather due to the eccentricity of Earths orbit. There are also minor effects with a cycle time or much greater than 1,000 years. These also due to variations in Earths orbit.

> **Comments:**
> **username_2**: Don't discount the variation due to Earth's orbit eccentricity.  
> **username_1**: @Jan Dvorak. Absolutely correct.  I assumed questioner was looking for a variation due to the sun itself.  A bad assumption on my part. I will update my answer after I determine difference.  
> **username_3**: Could you add how the brightness of the Sun 1000 years ago is known?  
> **username_1**: I stated it was only speculation really.  

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