In Stellarium version 0.9.0, star catalogues are split into 9 files, which contain stars of varying brightness. These files can be found in the <installation directory>/stars/default/. Only the smaller four of these files come with Stellarium in the main package to keep the size manageable.
Here is a list of all available catalogues. The RAM needed column is an estimate. (MNG managed to load file 7 with 512 M ram, but only just. YMMV).
|File name||Star Count||Magnitude Range||File Size||RAM needed||Availability|
|stars_0_0v0_0.cat||5,013||m < 6.0||138K||256M||In default package|
|stars_1_0v0_0.cat||21,999||6.0 <= m < 7.5||602K||256M||In default package|
|stars_2_0v0_0.cat||151,516||7.5 <= m < 9.0||4.1M||256M||In default package|
|stars_3_0v0_0.cat||434,064||9.0 <= m < 10.5||4.2M||256M||In default package|
|stars_4_1v0_0.cat||1,725,497||10.5 <= m < 12.0||17M||512M||Separate download|
|stars_5_1v0_0.cat||7,669,011||12.0 <= m < 13.5||44M||512M||Separate download|
|stars_6_2v0_0.cat||26,615,233||13.5 <= m < 15.0||153M||512M||Separate download|
|stars_7_2v0_0.cat||57,826,266||15.0 <= m < 16.5||333M||512M (just!)||Separate download|
|stars_8_2v0_0.cat||116,923,084||16.5 <= m < 18.0||674M||1024M?||Separate download|
NOTE: when downloading from this page, do not right-click and save as - left click. These are not direct download links - they are links to the list of download mirrors. Left click on them, and wait for your download to start.