Mikea1985 / orbit_cheby

convert input cartesian orbital positions to chebyshev representations, saved as dictionaries of chebyshev polynomials

cheby_checker

Python code related to orbital ephemeris calculations (for solar system objects) using fast chebysheb polynomial representations.

Functionalities exist/will-exist to:

• Perform n-body integrations (using a custom REBOUND wrapper) based on inital orbital states provided from an ORBFIT orbital fit to observations;
• Convert the output from n-body integrations (in the form of periodic output of posn, vel, covar, etc) into chebyshev polynomial representations;
• Conduct ephemeris calculations;
• Check the residuals between observations and expected positions from previous orbit extrapolations (pChecker-v2);
• Calculate the objects which are likely to be within the Field-of-View of a telescope (MPChecker-v2);
• Attribute observations (of unknown designation) to known objects (CheckID-v2);
• Identify archival observations (ITF or designated) of new objects (s9m-v2);

Architecture of Data Flow

• Checking_MPChecker_PCheck_CheckIDX_s9m_sifter.png

Installation / prerequisites

In order to get the NBODY part of the code working, one needs to have REBOUND/REBOUNDx installed. The proceedure pasted below was required to get the code working on machines operated by MA & MJP. Obviously this is non-optimal, but one would hope it could be automated (via setup.py) in the future.

• cd /home/mikea/Github

• git clone https://github.com/hannorein/rebound.git

• cd rebound

• make clean; make

• export REB_DIR=/home/mikea/Github/rebound

• cd ../

• git clone -b holman https://github.com/matthewholman/reboundx.git

• The following step is necessary until holman merges pull request from MA

• vi /Users/matthewjohnpayne/Envs/reboundx/examples/ephem_forces/ephem_forces.py

  This file is in :

  • ../../../reboundx/examples/ephem_forces/ephem_forces.py

  Assume that the library file will be in the same directory :

  • ../../../reboundx/examples/ephem_forces/libreboundx.so
  • rebx_location = os.path.join(os.path.dirname(os.path.realpath(file)), 'libreboundx.so' )

• cd reboundx/examples/central_force/

• perl -pi -e 's/OPENGL=1/OPENGL=0/g' Makefile

• make clean; make

• export REBX_DIR=/Users/matthewjohnpayne/Envs/reboundx

to-do : 2020-08-04

• See README in cheby_checker/cheby_checker code repo