Re: undisplayed (but maybe helpful) data

Bill J Gray Sep 5, 2011

Hi Tomas,

As Maik mentions, this data is stored in 'elements.txt'... but not
actually shown in the Find_Orb dialog, along with Tisserand invariants
relative to the earth and Neptune. Also stored in that file are the
state vector, perturbers used in the solution, and MOIDs relative to
eight planets. (MOIDs are usually only shown if they are small enough
to be interesting.)

There is also some housekeeping data; for example, it sometimes has
helped me to know which version of Find_Orb generated a particular set of
elements, and/or when the elements were generated.

The last two lines are used when generating a pseudo-MPEC, for
the URLs linking to a SkyMorph search and for the JPL visualization
tool (the one where you can see the orbit in 3D relative to the
rest of the solar system).

The only other significant data Find_Orb computes and doesn't show
is that in 'covar.txt'. This has the covariance and correlation
matrices, plus the eigenvectors/eigenvalues of the covariance
matrix. My hope is to use the eigendata in computing variant
orbits; i.e., if somebody asked for an orbit at +1.3 sigma from
nominal, the eigenvector data would be used for that purpose,
giving an orbit along the line of variation. The basic idea
actually doesn't look all that difficult, though the jargon
involved was pretty daunting at first.

'covar.txt' also has the sigmas for the orbital elements. That
data _is_ highly significant and will eventually be put on-screen.
Come to think of it, the Jupiter Tisserand data probably should be
shown if the Jupiter MOID is less than, say, two AU.

-- Bill