What is queue mode?

Queue mode (QM) is a type of telescope operation, where the observations are carried out by the telescope and instrument operators, without a direct involvement of investigators (PI or Co-I). Targets are selected from a number of approved programs, on the basis of various criteria, such as: the rank of the program, the priority of the target, observing conditions (seeing, sky transparency, humidity, moon phase and distance), air mass, telescope slewing time, current telescope configuration, etc. The main differences from the classical mode are that the PI and Co-Is are not present during the observations (at the summit, nor remotely), and objects from various programs can be selected for a given night. Observations for a given program can be done any time during the whole run allocated for the QM. Higher priority is given to higher-ranked programs, and the observations are carried out in conditions that are required by the PIs. The observing procedure is standardized, which ensures uniformity of all the data. Appropriate selection of objects allows to increase the effective time spent on target, thanks to reduced telescope slewing time and possibility of choosing programs that do not require certain strict criteria (for example, allow for worse seeing or sky transparency). The amount of data and scientific outcome of QM observations is thus typically higher than of the classical mode.

The difference when compared to the Subaru Telescope Service Program observations, available for some of the instruments1.1, but not for HSC, is that the service programs have fixed allocation of typically 0.5n, so their execution is dependent on many factors (like weather). Approved QM programs are executed during few runs, lasting in total at least several nights, thus there is more flexibility in observations and the probability of having the best-ranked proposals completed is much higher.

Figure 1.1: The flow of queue and classical modes from CfP to Data Delivery. The queue mode is right side blue diagrams and the classical mode is the left gray flow diagrams. Yellow circles mark Phase 1 and Phase 2.
Image Classic_Queue_flowchart

Queue operations are divided into several parts:

This document describes these steps in more details. In case of unanswered questions regarding the HSC queue mode please contact queue [at] naoj.org, or go to the QM website for more up-to-date information:
https://www.naoj.org/Observing/queue/.