1. How are the charts produced?
All charts are computer generated with finishing touches applied using vector graphics program Inkscape. The star data for the charts comes from the Hipparcos and Tycho-2 Catalogues of the Hipparcos satellite, which was launched by the European Space Agency in 1989 and operational until 1993.
The Hipparcos Catalogue is a high-precision data-set of more than 100,000 stars and was published in 1997 along with the lower precision Tycho Catalogue of more than a million stars. An enhanced catalogue Tycho-2 with 2.5 million stars was published in 2000. Double stars were checked using the Washington double star catalogue. Data for deep sky objects such as nebula, galaxies, open clusters, globular clusters etc are checked against various sources.
2. Will the charts always be free?
Absolutely. All charts will be free to download and we will try to make them available in as many different formats as possible.
3. What am I allowed to do with the charts?
This work is licenced under a Creative Commons License. What that means is basically you are free to download, use and/or distribute this work for non-commercial purposes with appropriate attribution. You can create and distribute derived works if they follow the same license.
4. I've seen a mistake in the charts. What shall I do?
5. I like the charts so much I would like to make a small financial contribution to the running costs.
By all means, all contributions no matter how small or large that help towards our server and running costs are always welcome.
Here's to dark stars!
Your freestarcharts.com team.