Where can we get historical data of planetary orbits?

[moonomaly]

I've seached a bit but can't find historical data on planetary orbits, specifically their orbital eccentricity.

Does something like that exist?

 

 

[furrysocks2]

16 minutes ago, moonomaly said:

I've seached a bit but can't find historical data on planetary orbits, specifically their orbital eccentricity.

Does something like that exist?

Define "historical"?

[moonomaly]

Records kept to record any changes, ie; is the orbital eccentricity decreasing over time.

[Stu]

Just now, moonomaly said:

Records kept to record any changes, ie; is the orbital eccentricity decreasing over time.

Over what sort of time period though?

[moonomaly]

As long as possible would be good to get a larger dataset.

[Stu]

Any good?

http://ephemeris.com/ephemeris.php

[furrysocks2]

Found a graph for Earth...

Source: http://www.museum.state.il.us/exhibits/ice_ages/eccentricity_graph.htm

[moonomaly]

Ephemeris! That's the word i couldn't remember when searching :/  Thank you both.

 

[furrysocks2]

What are you up to?

[furrysocks2]

17 minutes ago, moonomaly said:

Ephemeris! That's the word i couldn't remember when searching :/  Thank you both.

 

As an aside, here's some more words I've just learnt that may be useful to you in some context...

Quote

For a body orbiting the Sun, the point of least distance is the perihelion, and the point of greatest distance is the aphelion.
The terms become periastron and apastron when discussing orbits around other stars.
For any satellite of Earth including the Moon the point of least distance is the perigee and greatest distance the apogee.
For objects in Lunar orbit, the point of least distance is the pericynthion and the greatest distance the apocynthion.
For any orbits around a center of mass, there are the terms pericenter and apocenter. Periapsis and apoapsis (or apapsis) are equivalent alternatives.

Source: https://en.wikipedia.org/wiki/Apsis

[rockystar]

36 minutes ago, furrysocks2 said:

pericynthion

I've been looking for that word since I heard it for the first time in a talk at an astro meeting, about 6 weeks ago.

[furrysocks2]

A minor planet...

Quote

Chiron's orbit was found to be highly eccentric (0.37), with perihelion just inside the orbit of Saturn and aphelion just outside the perihelion of Uranus (it does not reach the average distance of Uranus, however). According to the program Solex, Chiron's closest approach to Saturn in modern times was around May 720, when it came within 30.5±2.0 million km of Saturn. During this passage Saturn's gravity caused Chiron's semi-major axis to decrease from 14.55±0.12 AU to 13.7 AU.

Source: https://en.wikipedia.org/wiki/2060_Chiron