Data Reduction and Related Software for Photographic Observations of Sunspots in the Yunnan Observatories

In this paper we present a data-reduction approach and related software for processing data of sunspots obtained from a photographic full-disk solar observation system established by us.When applied to data from our system the approach and software yield fundamental data and parameter values of sunspots, which can serve as the first-hand data to be accumulated and used by solar physicists to study underlying mechanisms of solar activities.The results of our data reduction include those of the relative sunspot numbers.sunspot-group numbers, sunspot locations, sunspot circular areas, sunspot surface areas, sunspot total areas, sunspot classifications, and distances from sunspots (or sunspot groups) to the solar center.As part of our data reduction we have incorporated a calculation program, which makes it possible to rapidly process daily sunspot data and give values of the mentioned parameters.Our approach may thus completely change the traditional method of manually handling photographic sunspot data, and greatly improve efficiencies of sunspot observation/data processing.It is still necessary for an observer to have certain observational experience and technical skill to use our approach, especially in grouping sunspots and evaluating group numbers.