Reducing data with error propagation

In order to avoid losing your error information during the reduction process, the recipe outlined below describes a recommended reduction path. Note that routines from both CCDPACK and KAPPA are employed. If you are working at a Starlink site, these will already be installed ready for your use. If you are not working from a Starlink site, you might wish to get these packages (e.g. from the Starlink Software Store on the World Wide Web) if you don't already have them.