Editing Orbital elements (section)

=== Elements by body type ===
The choice of elements can differ depending on the type of astronomical body. The eccentricity (''{{mvar|e}}'') and either the semi-major axis (''{{mvar|a}}'') or the distance of periapsis (''{{mvar|q}}'') are used to specify the shape and size of an orbit. The longitude of the ascending node ({{math|Ω}}) the inclination (''{{mvar|i}}'') and the argument of periapsis (''{{mvar|ω}}'') or the [[longitude of periapsis]] (''{{mvar|ϖ}}'') specify the orientation of the orbit in its plane. Either the Mean longitude at epoch ({{math|''L''<sub>0</sub>}}) the mean anomaly at epoch ({{math|''M''<sub>0</sub>}}) or the time of periapsis passage ({{math|''T''<sub>0</sub>}}) are used to specify a known point in the orbit. The choices made depend whether the vernal equinox or the node are used as the primary reference.<ref name="Green2">{{cite book |last=Green |first=Robin M. |title=Spherical Astronomy |date=1985 |publisher=Cambridge University Press |isbn=978-0-521-23988-2}}</ref><ref name="Danby2">{{cite book |last=Danby |first=J. M. A. |title=Fundamentals of Celestial Mechanics |date=1962 |publisher=Willmann-Bell |isbn=978-0-943396-20-0}}</ref>
{| class="wikitable"
|+Sets of orbital elements
!Object
!Elements used
|-
|Major planet
|{{math|''e'', ''a'', [[inclination|''i'']], [[ascending node|Ω]], [[longitude of periapsis|''ϖ'']], [[mean longitude|''L''<sub>0</sub>]]}}
|-
|Comet
|{{math|''e'', [[periapsis|''q'']], ''i'', Ω, [[argument of periapsis|''ω'']], ''T''<sub>0</sub>}}
|-
|Asteroid
|{{math|''e'', ''a'', ''i'', Ω, ''ω'', [[mean anomaly|''M''<sub>0</sub>]]}}
|}