<p>The central part of the diagram looks like it's illustrating the obliquity of the ecliptic. My guess is that the main vertical line is the ecliptic and the curve shows the declination of the Sun.</p>
<p>From top to bottom, the <a href="https://en.wikipedia.org/wiki/Ecliptic_coordinate_system#Spherical_coordinates" rel="nofollow noreferrer">ecliptic longitude</a> runs down from 0° to 180° (March equinox, June solstice, September equinox) with the corresponding declination curve on the right / south side, and then back up again from 180° to 360° (September equinox, December solstice, March equinox) on the left side.</p>
<p>Here's an equivalent diagram, using more modern conventions, and the J2000 value for the obliquity (~23.44°).</p>
<p><a href="https://i.sstatic.net/freWx.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/freWx.png" alt="Declination diagram" /></a></p>
<p><a href="https://sagecell.sagemath.org/?z=eJxdkD9PwzAQxfdI-Q4nT3blhvwpqAzeYO_AVlWRiY_gNrGjOAXDp-ecdmK653e_e6ezwR4UTBYeoNqXeeaRnnVT7Jrnep9nwbp2tUhwEhsw2Is8M9jxKMjXqXGnNisV75CgSKp5dkgLBr_w421KQqrNU7mN4iSBRwmlTNuFzDOAxXaXoI5N8krq_4zWqW39mJSOikSidMTQDvodB2LZazfYiQZh8K63y9Ugk8BekGynF-sdO_2faoP9RVUVFQX3szVEYlBs1Gc_sxX-mPWI6m2-oqQzJ-yWdk5hqqIPOBTh03_zm9JfyBkdVUyuZ-IP5BZjDw==&amp;lang=sage" rel="nofollow noreferrer">Plotting script</a></p>

CC BY-SA 4.0
2023-01-16T17:10:04.277Z
2023-01-16T17:29:57.593Z
2023-01-16T17:29:57.593Z
PM 2Ring
<p><a href="https://archive.org/details/KitabAlBulhan/page/n225/mode/2up" rel="nofollow noreferrer">Kitab al bulhan</a> or &quot;book of surprises&quot; is medieval Persian manuscript written in Arabic.</p>
<p>According to <a href="https://en.wikipedia.org/wiki/Book_of_Wonders" rel="nofollow noreferrer">Wikipedia</a>:</p>
<blockquote>
<p>The contents include subjects on astronomy, astrology and geomancy, including a section of full-page illustrations, with plates dedicated to the discourse topic, e.g. a folktale, a sign of the zodiac, a prophet, etc.</p>
</blockquote>
<p>It has following illustration in one of its pages (archive.org page 243). It is the only drawing in the book that has geometrical figures in it. (edit: i was wrong - there are actually many tables and diagrams)</p>
<p>Do you have any idea what it is about and is it related to astronomy?
Is it some kind of calendar?</p>
<p><a href="https://i.sstatic.net/l3SNA.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/l3SNA.jpg" alt="enter image description here" /></a></p>
<p>Google text translation works some of the words:</p>
<p><a href="https://i.sstatic.net/s8jh3.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/s8jh3.jpg" alt="enter image description here" /></a></p>
<p>So it looks like there are &quot;north&quot; and &quot;south&quot; and some names of star constellations, stars etc. Maybe zodiac stars/constellations? It may be related to astronomy or astrology.</p>

CC BY-SA 4.0
2023-01-16T12:23:41.163Z
Any context? Can you translate any of the writing?
ProfRob
CC BY-SA 4.0
2023-01-16T13:58:39.903Z
i found this article about the book https://www.slv.vic.gov.au/sites/default/files/La-Trobe-Journal-91-Stefano-Carboni.pdf . according to wikipedia "The contents include subjects on astronomy, astrology and geomancy, including a section of full-page illustrations, with plates dedicated to the discourse topic, e.g. a folktale, a sign of the zodiac, a prophet, etc. " https://en.wikipedia.org/wiki/Book_of_Wonders. I dont know is this drawing related to astronomy or something else. This looks like to be only drawing in the book that looks to have geometric figures. I can't translate it.
SamiM
CC BY-SA 4.0
2023-01-16T14:09:00.777Z
looks like all or most of the drawings of kitab al bulhan can be found in wikimedia commons site: https://commons.wikimedia.org/w/index.php?search=kitab+al+bulhan&title=Special:MediaSearch&go=Go&type=image
SamiM
CC BY-SA 4.0
2023-01-16T14:35:18.467Z
Perhaps a better subject for [history.se] or [hsm.se].
StephenG - Help Ukraine
CC BY-SA 4.0
2023-01-16T20:23:24.910Z
Aye, the translation somewhat hints that it is about astronomy. I retracted my close vote.
planetmaker
CC BY-SA 4.0
2023-01-17T01:28:59.883Z
I also retracted my close vote although I am still not convinced as most of it is Astrology. Also, you might want to add the details in the question itself and delete your comments.
Nilay Ghosh
<star><history><constellations><zodiac>
What is this drawing about in "kitab al bulhan"?
SamiM
# What is this drawing about in "kitab al bulhan"?

(Asked by: username_0 on 2023-01-16)

[Kitab al bulhan](https://archive.org/details/KitabAlBulhan/page/n225/mode/2up) or "book of surprises" is medieval Persian manuscript written in Arabic.

According to [Wikipedia](https://en.wikipedia.org/wiki/Book_of_Wonders):

> The contents include subjects on astronomy, astrology and geomancy, including a section of full-page illustrations, with plates dedicated to the discourse topic, e.g. a folktale, a sign of the zodiac, a prophet, etc.

It has following illustration in one of its pages (archive.org page 243). It is the only drawing in the book that has geometrical figures in it. (edit: i was wrong - there are actually many tables and diagrams)

Do you have any idea what it is about and is it related to astronomy?
Is it some kind of calendar?

[![enter image description here](https://i.sstatic.net/l3SNA.jpg)](https://i.sstatic.net/l3SNA.jpg)

Google text translation works some of the words:

[![enter image description here](https://i.sstatic.net/s8jh3.jpg)](https://i.sstatic.net/s8jh3.jpg)

So it looks like there are "north" and "south" and some names of star constellations, stars etc. Maybe zodiac stars/constellations? It may be related to astronomy or astrology.

**Tags:** star, history, constellations, zodiac
> **Comments:**
> **username_1**: Any context? Can you translate any of the writing?  
> **username_0**: i found this article about the book https://www.slv.vic.gov.au/sites/default/files/La-Trobe-Journal-91-Stefano-Carboni.pdf . according to wikipedia "The contents include subjects on astronomy, astrology and geomancy, including a section of full-page illustrations, with plates dedicated to the discourse topic, e.g. a folktale, a sign of the zodiac, a prophet, etc. " https://en.wikipedia.org/wiki/Book_of_Wonders. I dont know is this drawing related to astronomy or something else. This looks like to be only drawing in the book that looks to have geometric figures. I can't translate it.  
> **username_0**: looks like all or most of the drawings of kitab al bulhan can be found in wikimedia commons site: https://commons.wikimedia.org/w/index.php?search=kitab+al+bulhan&title=Special:MediaSearch&go=Go&type=image  
> **username_2**: Perhaps a better subject for [history.se] or [hsm.se].  
> **username_3**: Aye, the translation somewhat hints that it is about astronomy. I retracted my close vote.  
> **username_4**: I also retracted my close vote although I am still not convinced as most of it is Astrology. Also, you might want to add the details in the question itself and delete your comments.  

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## 1 answers

### Answer by username_5 on 2023-01-16. Score: 3

The central part of the diagram looks like it's illustrating the obliquity of the ecliptic. My guess is that the main vertical line is the ecliptic and the curve shows the declination of the Sun.

From top to bottom, the [ecliptic longitude](https://en.wikipedia.org/wiki/Ecliptic_coordinate_system#Spherical_coordinates) runs down from 0° to 180° (March equinox, June solstice, September equinox) with the corresponding declination curve on the right / south side, and then back up again from 180° to 360° (September equinox, December solstice, March equinox) on the left side.

Here's an equivalent diagram, using more modern conventions, and the J2000 value for the obliquity (~23.44°).

[![Declination diagram](https://i.sstatic.net/freWx.png)](https://i.sstatic.net/freWx.png)

[Plotting script](https://sagecell.sagemath.org/?z=eJxdkD9PwzAQxfdI-Q4nT3blhvwpqAzeYO_AVlWRiY_gNrGjOAXDp-ecdmK653e_e6ezwR4UTBYeoNqXeeaRnnVT7Jrnep9nwbp2tUhwEhsw2Is8M9jxKMjXqXGnNisV75CgSKp5dkgLBr_w421KQqrNU7mN4iSBRwmlTNuFzDOAxXaXoI5N8krq_4zWqW39mJSOikSidMTQDvodB2LZazfYiQZh8K63y9Ugk8BekGynF-sdO_2faoP9RVUVFQX3szVEYlBs1Gc_sxX-mPWI6m2-oqQzJ-yWdk5hqqIPOBTh03_zm9JfyBkdVUyuZ-IP5BZjDw==&lang=sage)


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