先前老看到一堆資料
MPC FORMAT 內的資料說明
http://www.cfa.harvard.edu/iau/info/OrbElsExplanation.htmlEpoch
The epoch of osculation of the orbital elements.
M
Mean anomaly at the epoch.
n
Mean daily motion (in degrees/day).
a
Semimajor axis (in AU).
z
Reciprocal semimajor axis (in 1/AU).
q
Perihelion distance (in AU).
e
Orbital eccentricity.
P
Orbital period (in years).
Peri.
The J2000.0 argument of perihelion (in degrees).
Node
The J2000.0 longitude of the ascending node (in degrees).
Incl.
The J2000.0 inclination (in degrees).
P and Q vectors
The vectors P and Q are an alternate form of representing the angular elements Peri., Node and Incl. For an explanation of how to convert between the two sets of quantities you are referred to standard celestial mechanics textbooks.
U
Uncertainty parameter.
Not all of these quantities will be given with every orbit, but enough information will always be given to describe an orbit completely.
The following two quantities are not orbital elements but are generally given with them.
H
Absolute visual magnitude. A table converting H to a diameter is available.
G
Slope parameter. For an explanation of the H,G magnitude system refer to Application of Photometric Models to Asteroids, Bowell et al., in Asteroids II, 524-556 (published by the University of Arizona Press, ISBN 0-8165-1123-3) and the references therein.
另個是彗星亮度
RA, Dec分別是赤經(Right Accession)和赤緯(Declination),
Delta(Δ)是彗星到地心的距離(以天文單位為單位) 表彗地距 (AU)
r是彗星到日心的距離(以天文單位為單位)
Elong是從地球看, 彗星相對太陽的張角 (太陽 -- 地球 -- 彗星)
。
Phase是從彗星看, 地球相對太陽的張角，也就是位相 (太陽 -- 彗星 -- 地球)
m1是彗星的亮度(單位是星等). (m2是彗核的亮度)
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軌道6 要素
q (perihelion distance近日點距離) AU
e (eccentricity偏心率) = 1.000301
i (inclination軌道斜角) = 77.827680
q (perihelion distance近日點距離) = 0.1707540 AU
TP (time of perihelion passage過近日點時刻) = 2007-01-12.80
OMEGA (longitude of ascending node 升交點黃經) = 267.413470
小寫omega (argument of perihelion近日點幅角) = 155.972290
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