Operations Simulation - Overview

The LSST Project developed the Operations Simulator to verify that the LSST Science Requirements could be met with the telescope design. It was used to demonstrated the capability of the LSST to deliver a 27,000 square degree survey probing the time domain and with 20,000 square degrees for the Wide-Fast-Deep survey, while effectively surveying for NEOs over the same area.  Currently, the Operations Simulation Team is investigating how to optimally observe the sky to obtain a single 10-year dataset that can be used to accomplish multiple science goals. 

Operations Simulator

The Simulator has a sophisticated model of the telescope and dome to properly constrain potential observing cadences.  This model has also proven useful for investigating various engineering issues ranging from sizing of slew motors, to design of cryogen lines to the camera. 

The Simulator is capable of balancing cadence goals from multiple science programs, and attempts to minimize time spent slewing as it carries out these goals. Ten years of LSST operations can be simulated using realistic seeing distributions, historical weather data, scheduled engineering downtime and current telescope and camera parameters. 

Achievements

• Demonstrated the need for a 9.6 square degree field of view.
• Motivated the need for 5 filters in the dewar instead of 4 filters based on filter usage per night.
• Provided survey coverage statistics by site to the Site Selection Committee.
• Assessed the impact on the survey of various telescope changes, such as dome crawl.
• Supported engineering requirements analysis.

 Future Work

• Develop multiple scheduling algorithms or strategies.
• Expand LSST observing modes (e.g., more flexible cadences)
• Experiment with dithering algorithms.
• Include higher fidelity sky brightness models (e.g., twilight & scattered light).
• Implement an improved weather model.
• Include logic to plan observations based on upcoming events such as sunrise, downtime, or cloudy weather (not trivial).

Hammer-Aitoff projection of coverage on the sky representative of a simulated survey.