Abhijit Saha and Richard Green
The queue observing experiment on the WIYN telescope has been very successful. We have been able to explore techniques of ground-based queue observing well in advance of the advent of Gemini. We have learned important lessons about the impact of tuning the "rules" of executing the queue and the relation of expectations to user satisfaction. We have quantitative information to assess the success rate of executing programs that depend on special conditions. We have the growing body of literature to explore the relative rates of publication for queue vs. classical observing. The success of this experiment was made possible by the extraordinary expertise and care of the queue observers.
NOAO is now preparing to take on support for observations with the Gemini telescopes, including enhancement of its queue observing program. Consequently, a shift in observing support resources has been required. We must therefore conclude queue observing on the WIYN telescope in the manner that has become familiar to users at the end of the current semester (2000A). Most WIYN proposals for upcoming semesters must be submitted for classically scheduled programs. We hope that for most this decision creates only a minor increase in inefficiency and/or inconvenience, with the science goals still obtainable in the "classical" way.
However, there are some types of programs that are uniquely suited to service/queue observing. They include trying out ideas to obtain proof of concept or acquisition of optical ground-based data to support multi-wavelength observations through the "2-hour queue". Also valued are synoptic monitoring (a small fraction of a night, every so often) and target of opportunity (ToO) programs. In order to retain some of these unique science-enabling modes, we will continue with a modified "2-hour queue" and explicit support for synoptic observations.
A few nights will be reserved, mainly for "2-hour" queue programs. On other nights, which are allocated to observers in classical mode, some fraction of the night may be reserved for synoptic and ToO observations. These programs will be scheduled in advance, including the specific part of the night that will be used by an NOAO queue-observer. The total amount of time that is allocated in these ways will depend on both the number of proposals highly ranked and the observing resources available. As a very rough guide, we expect to be able to support 3 or 4 full nights for the "2-hour queue" mode, and some 10 additional quarter nights for synoptic monitoring and ToO programs.
With the current instrument complement and the limited number of queue observing hours, there will be restrictions on available modes. Synoptic programs will be confined to imaging only. Spectroscopic monitoring programs cannot be done on nights shared with the queue, since the regularly scheduled observer's setup will presumably be different from that of the monitoring program. For 2-hour queue programs, the highest ranked proposal will determine the configuration of Hydra or Densepak and the bench spectrograph on any given night. Thus, a maximum of three or four configurations will be used in a semester, based on TAC ranking.
Within this framework, the queue observers will do their best to match the best observing conditions to programs that require it. However, with a much reduced pool of observing time, there will be fewer instances of the "best conditions." In addition, exploitation of optimal conditions is no longer a primary objective of WIYN queue observing. We urge queue proposers to be mindful of this. We also urge users to obtain photometric zero-point calibrations independently of the "mini-queue," since these are an inefficient use of a now very small pool of time. With the limited resources, our eye will be towards enabling programs with high TAC grades that CANNOT be done in other ways.