<p>I've been reading about the Earth's analemma from <a href="https://en.wikipedia.org/wiki/Analemma" rel="nofollow noreferrer">Wikipedia</a>, and I am having trouble visualizing one component. Let's build up to my question.</p>

<ol>
<li><p>If the Earth had a circular orbit and no axial tilt, the analemma would be a dot.</p></li>
<li><p>If the Earth had an eccentric orbit and no axial tilt, the analemma would be a east-west line.</p></li>
<li><p>If the Earth had a circular orbit and axial tilt, the analemma would be symmetric figure eight.</p></li>
</ol>

<p>My question:  In situation 3, I understand the north-south variation of the symmetric analemma, but I don't understand why there would be symmetric east-west variation.</p>

<p>Why does the Earth's axial tilt create an east-west variation in the analemma?</p>

CC BY-SA 3.0
2018-04-24T02:15:42.760Z
Related: [Effect of the obliquity of the ecliptic / tilt of the Earth on the equation of time](https://astronomy.stackexchange.com/questions/25567/effect-of-the-obliquity-of-the-ecliptic-tilt-of-the-earth-on-the-equation-of-t)
Mike G
CC BY-SA 3.0
2018-04-24T12:08:03.930Z
There's a detailed explanation in this document [The Analemma for  
Latitudinally-Challenged People](http://www.math.nus.edu.sg/aslaksen/teaching/analemma.pdf).
StephenG - Help Ukraine
CC BY-SA 3.0
2018-04-24T15:05:51.060Z
The east-west variation in the analemma **is** the equation of time, making this a duplicate of the previously cited linked question.
David Hammen
<orbit><earth>
Why does the Earth's axial tilt create an east-west variation in the analemma?
Nick Vence
# Why does the Earth's axial tilt create an east-west variation in the analemma?

(Asked by: username_0 on 2018-04-24)

I've been reading about the Earth's analemma from [Wikipedia](https://en.wikipedia.org/wiki/Analemma), and I am having trouble visualizing one component. Let's build up to my question.

1. If the Earth had a circular orbit and no axial tilt, the analemma would be a dot.
2. If the Earth had an eccentric orbit and no axial tilt, the analemma would be a east-west line.
3. If the Earth had a circular orbit and axial tilt, the analemma would be symmetric figure eight.

My question: In situation 3, I understand the north-south variation of the symmetric analemma, but I don't understand why there would be symmetric east-west variation.

Why does the Earth's axial tilt create an east-west variation in the analemma?

**Tags:** orbit, earth
> **Comments:**
> **username_1**: Related: [Effect of the obliquity of the ecliptic / tilt of the Earth on the equation of time](https://astronomy.stackexchange.com/questions/25567/effect-of-the-obliquity-of-the-ecliptic-tilt-of-the-earth-on-the-equation-of-t)  
> **username_2**: There's a detailed explanation in this document [The Analemma for   Latitudinally-Challenged People](http://www.math.nus.edu.sg/aslaksen/teaching/analemma.pdf).  
> **username_3**: The east-west variation in the analemma **is** the equation of time, making this a duplicate of the previously cited linked question.  

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## 0 answers

