Tangra is a large project that has consumed a lot of my time and continues to do so. It has taken more than a year of development, observing and testing even before the first public beta version was released. To show your support for the project and encourage future improvements you can license your copy for a small fee. Licensed users will receive technical support and will be able to use functionality that is not available in the free version (such as Astrometry). The table below shows the functionality that is available in the free version and in the paid version:

Functionality Free Version Paid Version   Functionality Free Version Paid Version Asteroidal Occultations YES YES   Use Dark and Flat Frames NO YES Exporting to FITS Format YES YES   PSF Fitting Methods 1 2 Receive Technical Support NO YES   Save Customized Colours NO YES Astrometry NO YES   Recent Files List NO YES