# GAIA DR1

### The first GAIA data release is now available and can be used with Skychart

The first Gaia data release, Gaia DR1, consisting of astrometry and photometry for over 1 billion sources brighter than magnitude 20.7 in the white-light photometric band G of Gaia. The Gaia Data Processing and Analysis Consortium (DPAC) processed the raw measurements collected with the Gaia instruments during the first 14 months of the mission, and turned these into an astrometric and photometric catalogue.

You can read more detail about GAIA DR1 in the release documentation

DR1 is a preliminary release of the GAIA data and some sky area are still incomplete.
Do not use this data if complete sky coverage is important for you.

The same limitation with the same “hole” apply to the other catalog based on GAIA DR1, like UCAC5 or HSOY.

### Use with Skychart

You can immediately use the GAIA DR1 data with Skychart by using the VO catalog feature.

Make a chart with a FOV of less than one degree in the area of interest.
Open the Catalog settings.

Click Add in the VO catalog tab and search for GAIA, select the catalog I/337, click Select catalog.

Select the first tab I/337/gaia, enter the default magnitude: 20, click Download catalog.

Make sure the GAIA row is green and click the OK button.
You can return to the screen later to load the data for a new area with a click on the arrow in the Reload column.
Beware that the one degree FOV around M13 take 28 MB of data to download, so do not do it on large area.

### Use a local catalog

You can also download this catalog for local offline use.
The easiest way is to download the catalog I prepare using Bittorent but you have the option to process the original data yourself.
The ready to use catalog include the fields: source_id, ra, dec, phot_g_mean_mag, no search index.

You can download this catalog using Bittorent, download size is 19 GB:

- Get the torrent file
- Open the torrent file in your bittorrent client software. You can eventually select only the zone directory you want. Always get the header file gaia.hdr.zip.
- Unzip every file to the same directory but keep the directory structure. Then open the file gaia.hdr from the Skychart menu Setup/Catalog/Catalog “Add” button.
- Please keep seeding to help other to get the data!

To build the catalog yourself using Catgen process as follow:

- Download my files I use to build the above catalog and use them as example.
- The file download.txt contain the download URL and a ready to use wget command.
- The file gaia_extract.sh is a shell script to format the csv data for use with Catgen. You can edit the script if you want to include other data field but be conscious this first release do not include more than the position and magnitude for 99.99% of the stars. On Windows you can run this script from the Cygwin shell.
- From Catgen open the example gaia.prj file and make the change you want before to run.