final boolean relativity = false; // whether to include relativity
final double lambda = 600.0; // wavelength in nm
GaiaSimuTime time = tr.getGSTime();
Astrometry ast = star.getAstrometry();
double trAlpha = ast.getCoMRSAstrometricParam(time, relativity).getAlpha();
double trDelta = ast.getCoMRSAstrometricParam(time, relativity).getDelta();
GVector3d comrs = ast.getCoMRSPosition(time, relativity);
System.out.println(comrs);
System.out.println(time);
System.out.println(tr.getFov());
GVector3d fprs = gaia.fromCoMRStoFPRS(comrs, time, tr.getFov(), GaiaSimuEnums.FpField.AF, lambda);
GVector3d fieldAngles = gaia.fromFPRStoFieldAngles(fprs, tr.getFov());