The correct person to look at this is Amy and she will be back from maternity leave on Oct 28. I get back on Nov 1 from my latest trip (ADASS, NRAO-CV, etc). We have planned an overhaul of some of the interpolation things in CLCAL - but Tsys is a bad one to interpolate in that Tsys is quite often source dependent (backgroud emission, spillover etc etc) Eric Greisen