An Example Survey
After a simulated survey is generated, post-processing of the data results in a number of statistics, graphs, and histograms designed to characterize the survey. The post-processing code base, Simulated Survey Tools for Analysis and Reporting, is flexible enough so that new figures of merit may be added. Here are some examples of currently implemented metrics.
To access data files and reports for the current Reference Survey as well as for other simulated surveys, visit the password protected Data Access page.
Summary Statistics
Duration |
10 years |
Total visits |
2,685,127 |
Visit length |
34 seconds (2x15s exposure, 2x1s shutter, 1 readout) |
Average slew time |
6.4 seconds |
Ratio of observe + slew time to possible observe time |
0.739667 |
Number of nights with no observations |
397 |
Observing Mode Statistics
| Deep Wide Survey | 20,000 square degrees to a uniform depth of u: 26.5 g: 27.4 r: 27.5 i: 26.9 z: 26.1 y: 24.9 |
| Northern Ecliptic | 3300 square degrees ~2.1 pairs per lunation |
Deep-Drilling |
70 square degrees 154 sequences of 100 days with > 85% of the requested observations |
| Galactic Plane | 1700 square degrees to uniform depth of u: 26.1 g: 26.5 r: 26.1 i: 25.6 z: 24.9 y: 23.5 |
| South Pole | 1700 square degrees to a uniform depth of u: 25.5 g: 26.4 r: 26.0 i: 25.3 z: 25.0 y:23.4 |
Depth
The 5 sigma coadded limiting magnitude (or depth) in each filter for each field is plotted in Aitoff projection for a 10-year simulated survey with the five observing modes described above. The 20,000 square degrees between -68 and +8 declination (excluding the crowded regions near the Galactic center) have limiting magnitudes of 26.5, 27.4, 27.5, 26.9, 26.1 and 24.9 in u, g, r, i, z, and y respectively.
Pairs of Visits
Showing the distribution of pairs of visits that are separated by 15 to 60 minutes per lunation, this plot is a figure of merit for determining asteroid orbits. There were 933,767 non-overlapping pairs in g, r, i, & z, yielding ~6 pairs per lunation for most of the survey area. Three pairs per lunation is needed to determine an orbit well enough to recover the object at a later time.
Source: American Astronomical Society 213th Meeting, Poster Exhibit, "LSST: Cadence Design and Simulation", K.H. Cook et al., 460.04