TheSky with Gaia DR2 Support

Be sure to maintain your software subscription to get access to the latest software installers and updates! What is Gaia?
Gaia DR2

Why use Gaia?
Minimum System Requirements
Gaia FAQs
How can I install the latest version of TheSky?

What is the Gaia Data Release 2?

The European Space Agency’s Gaia satellite observation mission continues to produce the largest and most accurate star catalog on record, with precision astrometric, photometric and spectroscopic measurements on, at present, almost 1.7 billion stars. The current officially release catalog data is called Gaia Data Release 3 (DR3). 

Not quite billions, and billions of stars, but getting closer!

TheSky Professional Edition versions 10.5.0 build 13096 and later (initially released in June, 2021) can display Gaia star positions with milliarcsecond accuracy, their G/BP/RP mean magnitudes, spectral class, stellar temperature, and proper motion…that means TheSky can show you the stars’ distance from Earth, in light years, for up to 1.7 billion stars!

Why do I need Gaia stars?

In a nutshell, the more accurate the star catalog’s positions, the more accurate your measurements based on these stars will be.

Whether you’re using TheSky’s Image Link to perform an Automated Pointing Calibration and produce a TPoint Super Model that improves your telescope’s pointing and tracking, running a script that finds the astrometric position of double star companions, or studying dynamic nature of stellar proper motion for the past thousand years, you can count on the Gaia catalog to provide the best star accuracy.

Gaia DR2 Database Details

The native Gaia DR2 dataset contains over 1.2 terrabytes (TB) of star data. The entire database can be downloaded from the Gaia archive page.   When the complete dataset is present, TheSky Professional Edition’s Sky Chart displays every star from the Gaia catalog and can access the accompanying “metadata.”

If you do not have a super-fast internet connection, or do not want to clutter your computer’s drive with unnecessary data you may not need, TheSky Professional Edition offers two different Gaia star catalog subsets that should suit the needs of even the most ardent astronomer.

  • Large Gaia Subset: The larger Gaia subset contains the RA, Dec, magnitude, spectral class and proper motion for 1.7 billion stars.
  • Small Gaia Subset: The smaller Gaia subset contains about 100 million stars that are equally distributed across the celestial sphere and is ideal for determining the astrometric solution (a.k.a. plate solution) for photos as small as about 3 arc minutes across.

Table 1: Gaia DR2 Subset Databases

Catalog NameNumber of StarsLimiting
Size (GB)
Large Gaia Subset1.7 billion~1994
Small Gaia Subset100 millionn/a* 5

*Not applicable. TheSky’s Smaller Gaia Subset database was created to have a relatively equal distribution of stars across the entire celestial sphere. This ensures that the astrometric solution can be found for most optical systems in photos taken anywhere in the sky. While there are some 18th magnitude stars, we do not publish a specific limiting magnitude for this subset.

Minimum System Requirements

  • TheSkyX version 10.5.0 build 12940 and later is required to display Gaia data.  Choose the About TheSky command (Help menu on Windows/Linux, TheSkyX menu on macOS) to make sure you have a compatible version installed.  If not, click Help > Check for Updates and install the latest daily build.
  • The Databases module SSD Version 3 and later includes the small and large Gaia subset databases.
  • The small Gaia subset can be downloaded here (log in required).


Q. I already own TheSky Professional or TheSky Imaging and my subscription is up to date. How can I get the Gaia star catalog?

A. First, install the latest daily build from My account > My Downloads. Next, download the Gaia subset and follow the instructions on the Gaia subset download page to view them. If you want the Large Subset, purchase the Databases module.

Q. How do I configure TheSky to use the Gaia data?

A. Please see TheSky User Guide for details.

Q. Does TheSky support the Gaia Data Release 3 (DR3)?

A. Software Bisque is working on rebuilding TheSky’s Gaia DR3 subset databases now that Gaia DR3 has officially been released.

Q. I have a version of TheSky installed (versions 10.5.0 build 12978 and earlier) with no Gaia support. How to I get Gaia support?

A. If you have an older version of TheSky installed that does not support Gaia, and want to install a version of TheSky that includes Gaia support, first log in to and renew your subscription. Then, either:

The steps below describe two ways to install the latest version of TheSky with Gaia star catalog support.

Download and Install the Latest TheSky Pro Full Installer
  1. Determine the folder where TheSky was originally installed on your computer.
    • macOS: TheSky is always installed to the computer’s Applications folder.
    • Linux: TheSky AMD64 is installed to a folder named TheSky on the Desktop.
    • Windows: By default, TheSky is installed to the computer’s C:\Program Files (x86)\Software Bisque\TheSkyX Professional Edition folder. Otherwise, use Windows File Explorer to search for the file named “TheSkyX.exe” and note the name of the folder where this file resides.
  2. Before installing the later version of TheSky, backup TheSky’s settings first as described in this article.
  3. Click My account > My downloads, and download the latest TheSky Full Installer for your operating system. The latest full installer (about 6 GB in size) includes the Gaia star catalog.
  4. Run the latest full installer.
    • macOS: Drag and drop TheSky to the Applications folder.
    • Linux: When prompted, select TheSky folder on the computer’s Desktop for the destination.
    • Windows: When prompted, select the same installation folder as the existing version of TheSky (as determined in Step 1 above). Your existing TheSky settings will be preserved.


Download the Latest Daily Build and the Gaia Subset Separately
  1. Click My account > My downloads, and download the latest TheSky Daily Build Installer for your operating system.
  2. Download the Gaia DR2 Small Subset database and follow the Installing the Gaia DR2 Subset instructions on the download page.