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Hello, this message is destined to developers who know well the Stellarium
I basically would like to know which source files and functions I could reuse
to find in which one of the 12 constellations the moon and the sun are, at a
given time, and at a given location (lat,lon,alt).
I would really appreciate it if a willing developer could help me, as I am
quite lost in the source after having downloaded the current trunk...
Thank you in advance!
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The constellation lines depend on the culture and details of these are in sky
The other information is calculated from data in the ssystem.ini file using
the standard astronomical algorithms.
To find the location of any of the items from stellarium you just need to
enter the date-time and location of interest and select the item required from
the find menu. The constellation lines and boundaries can then be selected
from the main menu but will depend on the sky culture.
However the information will be relevant to the science of astronomy and some
folk law and may bear little relationship to astrology or religious calendars.
For this you can write your own sky culture to draw constellation lines
anywhere you wish.
Thank you very much Barry - your reply was insightful.
OK, I got you regarding the sky cultures - in fact, I should have precised
that what mattered to me was in which constellation of the zodiac the sun
and the moon are, at a given time and place. Doing my homework, I found that I
had to use the Western culture, so that's OK.
Now, about the computation, I'd like to calculate this programmatically rather
than using the full Stellarium app, so I need a bit more details... I saw that
ssystem.ini has the sun and moon objects defined - great. Where I need more of
your time, if you could, is to help me find the function (or sequence of
functions) I need to call in order to find out the sun and moon's current
zodiac constellation, given an earth location (lat, lon, alt), using the
standard astronomical algorithms you mentioned.
The information used to make the calculations of the sky are all contained in
the src folder of stellarium. If you understand C, C++ programing you should
be able to extract the information you need. There is no one source.
If you are not a programmer you will need to learn how. A good book on how to
make astronomical calculations is Astronomy with your Personal Computer by
Peter Duffet-Smith. All the algiorithms needed are explained with examples
written in BASIC. However as I said earlier due to precession the Zodiacal
calendar is about 2000 years out of date compared to the astronomical calendar
and all the algorithms are for the astronomical calendar.
If you search the internet you may be able to find a program already written
that will satisfy your needs
Hi Barry, thanks - I am a programmer, and I was just trying to get a jump
start because I saw that the code of Stellarium has many files... I have
downloaded all the source code, and I am about to be able to compile it under
Windows using Mingw... I may even contribute to the project and develop a
I do not understand what you wanted to say when you wrote that the Zodiacal
calendar is 2000 years old - in fact, I do not have any interest in the
Zodiacal calendar, I just have interest in the Zodiacal constellations. As
explained, I am trying to find the pieces of code that will allow me to find
out the Zodiacal position of the sun and the moon at a given date/time and at
a given location on earth (lat, lon, alt). Any hint very well appreciated!
I wrote a program many years ago that calculated the position of the Sun, Moon
and Planets. It also used a data base containing the coords of the western
constellations. This data base was also used to list the constellation the
object was currently in. I don't have the program any more but it used many
sub routines to make all the calculations using the algorithms from the book I
referred to above.
OK Barry, thank you, even if your comments do not help me much with
Stellarium's code, at least you have told me about that reference book. Unless
another developer helps me I will have to spend a large amount of time to
decrypt Stellarium's source, but that's OK...
You don't need the accuracy of the routines used in Stellarium for that kind
of application. You can use routines from 'Astronomy on the Personal
Download the file 'APCe_v3_Pas.zip' under 'Pascal source codes (zip, 130 kB)'.
These are from previous editions. The source code in the 4th edition is
written in C. Find the files minisun.pas and minimoon.pas. The coördinates
from these routines are accurate enough to predict rise and set times.
Constellation boundaries: http://cdsarc.u-strasbg.fr/viz-bin/ftp-
Note that during the first half of december, the sun is in Ophiuchus. You will
need 13 constellations.
Thank you very much Hendrik. To the point. Exactly what I needed!
See the newest version of my rise and set script
It calculates the current constellation the sun, moon and planets are in.
It only does the constellations near the Ecliptic (13 Zodiac, Auriga, Cetus,
Orion, Sextans) as such it's not good for Plutoids or the asteroids that drift
far out of the ecliptic band.
You can see the source in the script file
Thank you so much, qam1! This is all I could hope for, and it replies exactly to my question. You basically did all the work for me! Take care!