Marble: Constellation lines - tiny southern constellations
completed by: Illya Kovalevskyy
mentors: Torsten Rahn, René Küttner, Dennis Nienhüser
During Google Code-In the Stars Plugin has been revamped and constellation lines as well as Deep Sky objects have been added.
This task is about adding more objects. Check out Marble's source code (http://marble.kde.org/sources.php will tell you how) and open the file
marble/data/stars/constellations.dat
As a first exercise we want to add the following ones:
- Reticulum ( with exactly these constellation lines: http://en.wikipedia.org/wiki/File:Reticulum_IAU.svg)
- Corona Australis ( with exactly these constellation lines: http://upload.wikimedia.org/wikipedia/commons/d/da/Corona_Australis_constellation_map.png)
- Lupus ( with exactly these constellation lines: http://upload.wikimedia.org/wikipedia/commons/2/21/Lupus_constellation_map.png )
- Crater ( with exactly these constellation lines: http://en.wikipedia.org/wiki/File:Crater_IAU.svg )
- Ara ( with exactly these constellation lines: http://en.wikipedia.org/wiki/File:Ara_IAU.svg )
- Telescopium ( with exactly these constellation lines: http://upload.wikimedia.org/wikipedia/commons/2/21/Telescopium_constellation_map.png )
Creating the constellation lines works like this: you look up the stars one by one that are part of the lines: In the constellation Centaurus for example ( http://de.wikipedia.org/w/index.php?title=Datei:Centaurus_constellation_map.png&filetimestamp=20041212180049, done in a previous task) you could start with the Star named Toliman which is "Alpha Centauri" or short "Alp Cen". The abbreviation of the constellation name ("Cen") is listed in the Wikipedia article in the box on the right.
Now look up "Alp Cen" in the file
marble/tools/stars/catalog.dat
After some search it turns out there is no "Alp Cen" but "Alp1Cen" and "Alp2Cen" because Alpha Centauri is a double star. We take the brighter component (with the lower magnitude number which is +0.71 in this case). And we identify the first number in the catalog line which is "5459". The number "5459" is the number we need to enter into the constellations.dat filel Then we continue to do the same with the next star in the line: "Beta Centauri" ("Bet Cen") and find that the number at the start of the catalog line is 5267. etc. An index number "-1" is used to start a new line string. All stars are designated after the greek alphabet:
http://en.wikipedia.org/wiki/Greek_alphabet
You can find out more about the designation at:
http://en.wikipedia.org/wiki/Bayer_designation