Flexible observing modes employed at the WIYN Observatory

The WIYN 3.5 meter telescope on Kitt Peak, Arizona is operated by a consortium involving three universities and the National Optical Astronomical Observatories (NOAO) each with their own set of scientific requirements and research objectives. To meet this diversity a variety of operational modes are being used. It is the purpose of this paper to describe the experience acquired so far with queue scheduling, remote observing, consortium-wide coordinated programs, and student involvement. Observing time is block scheduled in such a way that each WIYN member receives their equitable distribution with respect to season and lunation. NOAO provides operations support and receives 40 percent of the observing time which is made available to the general astronomical community through the same mechanism as for other NOAO facilities. The largest fraction of this time, however, is devoted to queue scheduling. The remaining 60 percent of the observing time is divided among the three universities in proportion to their contribution to the capital costs of the observatory. Each university has its own approach to assigning observing time and utilizing their blocks. Among the modes employed are traditional on-site, service, and remote observing. The WIYN telescope supports rapid changing of instrumentation and it is common to do multiple-instrument observing during the course of a night. This also expedites the sharing of nights by more than one observer. The flexibility also provides the means to respond to targets of opportunity. In this paper we shall try to evaluate the ways in which this flexibility has been able to enhance scientific return.