Star catalogues
The star catalogue used by WinStars is the Gaia Early Data Release 3 (Gaia EDR3) published by the European Space Agency (ESA) on 15 December 2020. It contains 1,811,704,130 sources, with positions, parallaxes, proper motions and photometry; the G magnitude of the faintest sources is about 21. Full references are on the Sources of calculations and data page.
In the software, the catalogue is divided into three parts:
The part 1 contains objects of magnitude less than 10. It is the basic catalogue of WinStars.
The part 2 covers magnitudes between 10 and 13. This represents more than three million additional stars.
Finally, the third part requires an Internet connection to work. The magnitudes go from 13 to 20. This concerns more than one billion additional stars. The Gaia EDR3 catalogue itself reaches magnitude
Gof about 21: the third part stops before its faintest sources.
Note
Parts 2 and 3 are available to everyone. They are downloaded on demand and require an Internet connection.
Note
What the Gaia catalogue is. Gaia, an ESA mission launched in 2013, measures the positions, parallaxes and proper motions of a billion objects with an angular precision of about 0.02 to 0.03 milliarcsecond (mas) for the brightest stars, and about 0.5 mas near magnitude G = 20. The EDR3 release (15 December 2020) provides 1,811,704,130 sources with G, GBP and GRP photometry. The DR3 release (13 June 2022) adds about 333 million six-parameter astrometric solutions, radial velocities, classified spectra and light curves. Full references are on the Sources of calculations and data page.