A new candidate Reference Run, minion_1016, is being proposed to the LSST Change Control Board as a replacement for the current Reference Run, opsim3.61. An announcement will be issued here when it is approved.
The purpose of this post is to clarify some of the terminology that is used to describe simulated surveys generated by the Operations Simulator (OpSim).
- A “Reference Run” or “Reference Simulated Survey” is a specific simulated survey generated by a specific set of configuration files with a specific version of the OpSim code.
- A “Candidate Reference Run” is a specific simulated survey that is being (or will be) proposed to the CCB for approval as the new Reference Run.
- The collection of configuration files which completely specifies the cadence for each science goal (proposal) in the Reference Run is referred to as the “Baseline Cadence”, or “Baseline Observing Strategy.” Very often a set of simulations consisting of variations in the parameters of the Baseline Cadence is generated to explore a particular science objective.
There are two types of proposals (observing modes) used by OpSim and they are employed in three different ways in the Baseline Cadence. The two types are area distribution (WL) and time dependent (WLTSS).
Area distribution (weakLensConf or WL) observing modes consider how many field/filter combinations are requested versus how many have been accumulated.
- The GalacticPlaneProp.conf and the SouthCelestialPole.conf proposals collect field/filter combinations with no regard for timing or cadence, simply the number of visits to a field in a particular filter.
Time dependent (WLpropConf or WLTSS) observing modes can have complex cadence requirements in addition to field/filter observations requirements.
- The WFD.conf (WLTSS type; Wide-Fast-Deep, formerly known as Universal.conf) proposal is the primary way the WFD observing program has been simulated. The WLtype = True statement makes the proposal collect field/filter visits in tuples set with NumGroupedVisits = n, where for minion_1016 this is 2 for a pair (with the separation set by the window parameters), but otherwise does not consider cadence. It currently cannot use look ahead. The NorthEclipticSpur.conf proposal (covering the “north ecliptic spur”) is similarly designed.
- The DDcosmology1.conf (“deep drilling”) proposal is of the WLTSS type but has a more complex temporal implementation. This proposal collects sequences of observations in 5 selected fields for cosmological studies. There are two sets of sequences since the science requests all 6 filters and only 5 are mounted at any time. Once the sequence begins it is not interrupted.
More details of about the parameters in the configuration files may be found at http://ops2.lsst.org/docs/current/configuration.html