Updates to sims_movingObjects and sims_maf (Oct 2018)

solarsystem
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(Lynne Jones) #1

Please note that I’ve incorporated Michael Mommert’s updates to oorb into the LSST version of oorb, and thus updated sims_movingObjects accordingly! There were some other changes to accomodate this update, but ALSO, a significant update of methods available to generate the observations.

Previously, the only usable option for generating observations used (underneath) a linear interpolation between fixed true ephemeris positions in order to generate the positions at any given time.
This method is still available, but now there is an additional method available – you can use the “direct” method to generate exact ephemerides at the times of each observation. (underneath, what this does is generate a rough preliminary grid of ephemeride points, look for potential matches to observations based on a ‘roughTol’ tolerance value, and for those potential matches, then generate ephemerides at the exact time of each pointing).

In both cases, once you have an object that may be inside the field of view, you can match with either a ‘circle’ or the actual ‘camera’ footprint – new, you can now also choose a ‘rectangle’ for the field of view.
There are some changes in how you run “makeLSSTobs.py” to accomodate these new options.

You can access more detailed documentation on the sims_movingObject package, including these updates, at either https://sims-movingobjects.lsst.io/ or https://epyc.astro.washington.edu/~lynnej/sims_movingObjects/ (the first one would be the official, long-term home … but until DM Square helps me update the documentation and builds the additional framework to support sims documentation builds, it may potentially lag behind the epyc version of the documentation).

The MAF documentation has been updated in response to a request from Meg, to include a summary of what is calculated as part of the standard “run_moving.py” script: https://epyc.astro.washington.edu/~lynnej/sims_maf/ and specifically, https://epyc.astro.washington.edu/~lynnej/sims_maf/metricsRunMoving.html

Please note that sims_maf has ALSO been updated to accommodate the changes in makeLSSTobs.py.
Observations generated by makeLSSTobs.py in the current version come with metadata in the file itself; a series of comment lines starting with “#”, and will have a column called “geo_dist” which is the geocentric distance (as well as a helio_dist).
Observations generated by older versions of makeLSSTobs.py will not have this header information and will have a column called “Delta” which is the geocentric distance.
If you wish to use an older version of observations with a newer version of MAF, you should edit the column “Delta” to read “geo_dist”.