This section gives a brief guide to the initial stages of reducing MERLIN data to produce maps. Standard continuum data contains scans of a few minutes on the target, interspersed with scans on a phase calibrator (phase-cal). In addition there are observations of a flux-cal, a point source calibrator point-cal, a bandpass calibrator bp-cal) and a polarization position angle calibrator, pa-cal. One source usually serves for several of these purposes, see Appendix C.
Many processes can be carried out at alternative stages or in different ways. The procedures below are an attempt at a straightforward routine using the best readily available software at the present date. So if you are familiar with alternative methods at some stages there is not necessarily any reason to change, although you should make sure that you are familiar with recent improvements in software (e.g. the local program tdproc, or IMAGR in AIPS).