Re: undisplayed (but maybe helpful) data

andrew_j_walker Oct 12 12:39 AM

In the devel version (haven't checked the main version) these
are given right at the end of the file. Mine at the moment has this:

sigma_Tp 0.0429 days
sigma_e 0.000197
sigma_q 9.15e-005 AU
sigma_Q 13.1 AU
sigma_1/a 6.37e-005 1/AU
sigma_i 0.00208 deg
sigma_M 2.6e-005 deg
sigma_omega 0.0107 deg
sigma_Omega 0.000164 deg
sigma_a: 6.54 AU
sigma_P: 6.41e+004 days
P = 5734.34 years; U=4.6

Andrew

--- In find_orb@yahoogroups.com, "puck2017" <puck2017@...> wrote:
>
> Hi Bill,
>
> How would I go about decoding the covar.txt file if I all I wanted was the uncertainties in the 7 main orbital parameters?
>
> Thanks,
> Andy
>
>
> --- In find_orb@yahoogroups.com, Bill J Gray <pluto@> wrote:
> >
> > 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
> >
>