1. Calc - Updating for IERS Conventions (2010): Precession/Nutation – change to use IAU2006 precession model. Makes a difference of ~0.5 µas/yr from 2000.0. Add and/or modify UT1 and polar motion libration model (formerly called short period nutation effects). Typically a few µas effect on EOP’s, sub-psec effect on delays. Pole Tide – new mean pole model. Ocean loading – calculate new coefficients. Ocean pole tide loading (new model). Effect is typically no larger than 1.8/0.5/0.5 mm in U/E/N. Antenna thermal expansion model - ? [In Solve] Pressure loading and S1/S2 atmosphere tides - ? [In Solve] VMF - ? [In Solve]

2. Plans/Wishlist for Calc: Update to version 11: For IERS Conventions (2010). Finite distance model Thermal deformation (?) Pressure loading (?) VMF (?) ????? Modify inputs/outputs for νSolve and DiFX. Create C++ version.

3. Other Issues: Work with VLBA and/or other DiFX users for efficient use Of Calc. If processing time becomes an issue, several things can be done. Usage can be structured or computations saved to avoid re-computing the same things many times. Unused time derivatives and partials computations can be removed.