eLSST Operations Simulations
The LSST Operations Simulator
(OpSim) team in Tucson has developed a simulator to mimic actual day-to-day operations
of the telescope. The OpSim generates a database of "observations"
which contains information about the fields observed and conditions of each observation in that OpSim run.
How the OpSim chooses which fields to observe throughout the simulation is
controlled by a proposal system, where different science programs request RA/Dec
pointings appropriate for the weather conditions and time of observation. The
fields requested by each proposal are ranked depending on time constraints, slew
and filter change requirements, and priority of observation. While the OpSim can
be run many times with different proposal setups, the OpSim output currently being
used for science evaluation purposes is 'opsim3.61'. (Please note, we're still in a bit of a state of transition between opsim1.29 and opsim3.61, so please be patient until the switch is complete. The simulations are very similar).
For more background on the operations simulation, please see the documentation on the OpSim website.
Here at UW, we have been working with the Opsim team, adding some extra information to the basic Opsim output and creating tools to help evaluate science that depends on the cadence or pointing history in the Opsim. More documentation about this is available.
eLSST OpSim Tools
Quick Query InterfaceThe first tool available is the quick query interface, which provides an easy method to query the opsim pointing history. You can enter an RA and Dec pair, along with optional constraints (such as filter='g', for example) and the quick query tool will return to you the MJD and limiting magnitudes of each exposure which cover the given RA/Dec and fulfills the constraints. You can also optionally have all columns in the opsim output returned to you, either in a downloadable text file or an HTML table.
Lightcurve Sampling ToolThe second tool available is a lightcurve sampling query tool, where users can provide a lightcurve in one or more filters and receive magnitudes as could be measured in the operations simulation output. This is a set of python scripts.
Pixelization of the UW OpSim Database
To evaluate considerations such as the effect of dithering on weak lensing or photometric calibration, we are developing a pixelation of the opsim output which will support maps of whatever data is required (median seeing, number of visits, cumulative limiting magnitude, etc.). These are not online yet, but please let us know if there is a particular map you would find interesting.A preliminary report on the effects of dithering on cumulative limiting magnitude is available, as an example of the potential of pixelization.