<p>Azimuth is measured along the local horizon: 0° is geographic north, 90° is east, and so on.
Lines of equal azimuth converge at the <a href="https://en.wikipedia.org/wiki/Zenith" rel="noreferrer">zenith</a> and <a href="https://en.wikipedia.org/wiki/Nadir" rel="noreferrer">nadir</a>.</p>
<p>Hour angle is measured along the celestial equator: 0h is the local <a href="https://en.wikipedia.org/wiki/Meridian_(astronomy)" rel="noreferrer">meridian</a>, 6h is in the western sky, etc.
Lines of equal hour angle converge at the celestial poles.</p>
<p>In other words, the two angles are measured around different axes.
The angle between those axes is the complement of the observer's latitude.</p>

CC BY-SA 4.0
2020-08-14T14:08:10.583Z
2020-08-14T14:08:10.583Z
Mike G
<p>What is the difference between an hour angle and an azimuth angle? When I see illustrations of the two, the angles look very similar.</p>

<observational-astronomy><coordinate>
What is the difference between azimuth angle and hour angle?
Robben
# What is the difference between azimuth angle and hour angle?

(Asked by: username_0 on 2020-08-14)

What is the difference between an hour angle and an azimuth angle? When I see illustrations of the two, the angles look very similar.

**Tags:** observational-astronomy, coordinate


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## 1 answers

### Answer by username_1 on 2020-08-14. Score: 7 | Accepted answer

Azimuth is measured along the local horizon: 0° is geographic north, 90° is east, and so on.
Lines of equal azimuth converge at the [zenith](https://en.wikipedia.org/wiki/Zenith) and [nadir](https://en.wikipedia.org/wiki/Nadir).

Hour angle is measured along the celestial equator: 0h is the local [meridian](https://en.wikipedia.org/wiki/Meridian_(astronomy)), 6h is in the western sky, etc.
Lines of equal hour angle converge at the celestial poles.

In other words, the two angles are measured around different axes.
The angle between those axes is the complement of the observer's latitude.


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