<p>Is there any way of drawing the horizon on sky maps similar to the one attached?</p>
<p><a href="https://i.sstatic.net/VoQYp.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/VoQYp.png" alt="enter image description here" /></a></p>
<p>This is the complete chart in Stellarium:
<a href="https://i.sstatic.net/Huc37.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/Huc37.png" alt="enter image description here" /></a></p>

CC BY-SA 4.0
2021-07-18T16:01:42.183Z
If zenith angle is 0 degrees in the center and 90 degrees at the edge and you've been careful to plot your star map in polar coordinates with $r$ as zenith angle and $\theta$ as azimuth (or negative azimuth) then draw the zenith angle=90 degrees circle as your horizon. However, if all of that is not true, then your question should really be "How to convert a star map in RA/Dec to a sky map in zenith angle and azimuth?"
uhoh
CC BY-SA 4.0
2021-07-18T16:33:52.070Z
I added an image of the sky map with the horizon (the green circle). The map is a oblique stereographic projection (I think that's what it's called). I don't know how to make my question more specific, I want to know if there is any way of drawing the horizon without knowing the latitude of the observer.
John
CC BY-SA 4.0
2021-07-18T16:38:29.013Z
I see, thanks! I think you will need to find a different projection. I haven't used Stellarium in a long time, but I'll bet there is an option to make a star chart for you. I think that viewed like this it's impossible to draw a horizon and make a reasonably useful star chart.
uhoh
<star-maps>
How should I draw the horizon on a sky map?
John
# How should I draw the horizon on a sky map?

(Asked by: username_0 on 2021-07-18)

Is there any way of drawing the horizon on sky maps similar to the one attached?

[![enter image description here](https://i.sstatic.net/VoQYp.png)](https://i.sstatic.net/VoQYp.png)

This is the complete chart in Stellarium:
[![enter image description here](https://i.sstatic.net/Huc37.png)](https://i.sstatic.net/Huc37.png)

**Tags:** star-maps

> **Comments:**
> **username_1**: If zenith angle is 0 degrees in the center and 90 degrees at the edge and you've been careful to plot your star map in polar coordinates with $r$ as zenith angle and $\theta$ as azimuth (or negative azimuth) then draw the zenith angle=90 degrees circle as your horizon. However, if all of that is not true, then your question should really be "How to convert a star map in RA/Dec to a sky map in zenith angle and azimuth?"  
> **username_0**: I added an image of the sky map with the horizon (the green circle). The map is a oblique stereographic projection (I think that's what it's called). I don't know how to make my question more specific, I want to know if there is any way of drawing the horizon without knowing the latitude of the observer.  
> **username_1**: I see, thanks! I think you will need to find a different projection. I haven't used Stellarium in a long time, but I'll bet there is an option to make a star chart for you. I think that viewed like this it's impossible to draw a horizon and make a reasonably useful star chart.  

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## 0 answers

