packaging catalogs and license questions

[Mattia Verga]

Hello,
I would like to package some additional catalogs for Skychart, but I 
have some questions regarding license and to the package process.

First of all, as you can see on skychart download page [1], each package 
has more than one catalog inside. All of these catalogs are known to be 
public domain, but there's no license file specified either in catalogs 
or on original websites of the catalogs [2] [3]. Moreover, original 
catalog data is reworked by skychart's developer to fit the main program.
So, questions about license: Should I ask for a license file to be 
integrated? Who I should ask for the license file, skychart's developer 
or who make the original catalog data?

Now the technical questions. I suppose I must create new packages and 
requesting reviews for each catalog source instead of creating 
subpackages inside the main skychart specfile, right? For example, 
skychart-data-stars.spec will have stars catalogs and 
skychart-data-dso.spec will have dso catalogs, like on the skychart's 
website?
But what if inside the stars catalogs package two catalogs have 
different licenses?I must create different subpackages, right?

Final question. Since all these catalogs contain only data that only 
requires to be copied in the appropriate directory, there's no need to 
build anything. Can the specfile have a void %build section?

...well, quite a lot of questions! ;-) I hope someone can clarify me on 
this...
Mattia

[1] http://www.ap-i.net/skychart/en/download
[2] http://ad.usno.navy.mil/wds/
[3] http://www.astro.ku.dk/~erik/Tycho-2/