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kheider
2011-Sep-19, 07:38 PM
Do you guys think it would be better to list Proper orbital elements for main-belt asteroids (such as Ceres) on Wikipedia or do you think Osculating orbital elements (at a recent epoch) are easier for Joe Q. Public to understand? I feel Osculating orbital elements are easier for the public to verify without getting lost in conversions.

Ceres at JPL (epoch 2010-Jul-23):
http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=1

Ceres at AstDyS-2 (Synthetic Proper Elements):
http://hamilton.dm.unipi.it/astdys/index.php?pc=1.1.6&n=1

There is a discussion on Wikipedia about this and I would appreciate any feedback/comments.
http://en.wikipedia.org/wiki/Template_talk:Infobox_planet#Proper_Orbital_Elemen ts

-- Kevin Heider

cjameshuff
2011-Sep-19, 09:02 PM
Do you guys think it would be better to list Proper orbital elements for main-belt asteroids (such as Ceres) on Wikipedia or do you think Osculating orbital elements (at a recent epoch) are easier for Joe Q. Public to understand? I feel Osculating orbital elements are easier for the public to verify without getting lost in conversions.

Proper elements can be derived by simulation from osculating elements, the reverse is not true. Osculating elements give initial conditions that can be used to compute actual location, proper elements only give "typical" values that are rather useless for this purpose. If you have to pick one in exclusion to the other, osculating elements seem like the better choice.

TonyE
2011-Sep-19, 09:16 PM
I'll vote for osculating elements too!

kheider
2011-Sep-19, 11:05 PM
Do you guys think listing bother proper elements and osculating elements will confuse the casual reader?

Someone on Wikipedia is concerned with Wikipedia listing Ceres orbital period as 1680.5 days (Epoch 2009). Where as the proper elements show it to be closer to 1681.60 days. (The commenter is worried about people trying to calculate the synodic period and other values.)
Math: 360 degrees / "Synthetic mean motion in degrees/year (n)" * Julian years
Math: 360/78.1933*365.25=1681.601

I am thinking of adding a paragraph to explain the long-term "proper" orbital period, semi-major axis, eccentricity, and inclination. But I think listing any elements that would need to be solved by the reader to verify the source would only lead to needless confusion.

Hornblower
2011-Sep-20, 02:12 AM
To me this is a no-brainer. Put both sets of elements in, with a concise explanation of the differences. With good writing, there should be no confusion.

grapes
2011-Sep-20, 03:11 AM
Someone on Wikipedia is concerned with Wikipedia listing Ceres orbital period as 1680.5 days (Epoch 2009). Where as the proper elements show it to be closer to 1681.56 days. (The commenter is worried about people trying to calculate the synodic period and other values.)
Math: 360 degrees / "Synthetic mean motion (n)" * Gregorian calendar
Math: 360/78.1933*365.2425=1681.567Wait, the other link has n as .2143281753212812 degrees per day, 360 divided by that is 1679.667 days?

kheider
2011-Sep-20, 05:49 AM
AstDys lists mean motion in deg/yr. JPL lists it in deg/d. (I will need to detail this in the explanation)
The epoch 2010-Jul-23 osculating period is 1679.6 days.

Ceres at JPL (epoch 2010-Jul-23):
http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=1

Ceres at AstDyS-2 (Synthetic Proper Elements):
http://hamilton.dm.unipi.it/astdys/index.php?pc=1.1.6&n=1

-- Kevin Heider

kheider
2011-Oct-01, 09:37 PM
Ceres now has osculating and proper orbital elements...
http://en.wikipedia.org/wiki/Ceres_(dwarf_planet)

-- Kevin Heider