The Naval Observatory Merged Astrometric Dataset (NOMAD) contains astrometric and photometric data for over 1 billion stars derived from the Hipparcos , Tycho-2 , UCAC2 , and USNO-B1.0 catalogs for astrometry and optical photometry, supplemented by 2MASS near-infrared photometry.
Thank to the effort of Oleg Maliy we can now use this catalog with Cartes du Ciel!
The catalog is available to download by Bittorrent. It is presented in the form of text file for each zone area (South Polar Distance).
You need to run Catgen to use this data with Skychart but this as the advantage to let you select the data you need for the catalog size you want.
This also make it easy to use this data outside of Skychart.
For each star the files contain:
Update June 9 2018: A new torrent with working tracker is now available. This version is also fixed for the two data files that where previously in error.
And a final note: Please let the torrents active after you finish to download! We need your upload capacity to make the files available to all on the best condition.