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./contrib casaframevel.pro
casaframevel |
function casaframevel(ra, dec, mjd, sitelong, sitelat, siteelev, fromframe, toframe) |
Uses CASA library call to return the velocity of toframe relative to fromframe.
See dcfixvframe or fixvframe for the procedures intended for users to use. This function is primarily for use internal to those procedures. Note that the first time this function is called there will be a small delay while the shared library is loaded. Subsequent calls will be substantially faster.
This calls a function in a shared library that in turn invokes the necessary calls in the CASA library to calculate the relative frame velocities for the given pointing direction, site location, and modified Julian date (mjd). This function is only available in Green Bank and Charlottesville on linux machines because of the nature of the CASA library calls (this does not use pure IDL). This is an interrum solution while a more permanent solution for use more transparently in GBTIDL is researched and implemented.
Contributed By: Bob Garwood, NRAO-CV
radec = getradec(dc,2000.0,/quiet) ok = decode_veldef(dc.velocity_definition, veldef, velframe) vframe = casaframevel(radec[0],radec[1],dc.mjd,dc.site_location[0], $ dc.site_location[1], dc.site_location[2], $ dc.frequency_type, velframe)