Do the Iau2006XysData files get updated?

Where is this data sourced from?
Is it subject to get refreshed as the earth changes? Or it is fixed?

Thanks!
-Dave

Hi @dave_gould,

This data comes from the International Astronomical Union (IAU) and is based upon the position of a few hundred extragalactical objects like quasars etc. It is used to define a referance frame for our solar system. Because there is no significant change in position (relative to earth) of those extragalactical objects in the next few thousand years, I think the data will only change, if there is a major improvement of technology, which leads to less measurement uncertainty.

In Cesium it can e.g. be used to convert

  • ECEF (Earth Centered Earth Fixed, Point(0,0,0) is the earth center and the whole reference frame rotates with the earth)

to

  • ECI (Earth Centered Inertia, Point(0,0,0) is the earth center, but the referance frame does not rotate with earth rotation)

I hope that was helpful and not confusing. :wink:
Best, Lennart