#23662 1986-17JK has a small eccentricity, and exhibits the jumps in AOP, mentioned by Mike McGants. 1 23662U 86017JK 95330.29138255 .00095685 00000-0 69731-3 0 1091 2 23662 51.6649 61.2926 0003782 316.3693 43.6999 15.72510102558258 1 23662U 86017JK 95330.10070957 .00098678 00000-0 71949-3 0 1083 2 23662 51.6605 62.2665 0004078 280.8491 79.1598 15.72483587558223 1 23662U 86017JK 95329.71939707 .00101011 00000-0 73820-3 0 1070 2 23662 51.6581 64.2197 0004528 282.6594 77.3894 15.72417100558162 In the three revolutions 95330.10 - 95330.29, AOP leaped forward by 36 degrees, so it did only 2.9 anomalistic orbits ! I can't say this is reflected in the mean motion. I think both anomalistic and nodal period are slightly esoteric quantities. If a stable elliptic orbit had a rigid, rotating shape and low inclination (increasing AOP) and a constant MM, its nodal period would be much shorter when AOP was close to 180 degrees, which I think violates the principle of conservation of energy. If the "nodal" period, measured at an arbitrary point along the orbit, is a constant, the ellipse is not rigid, but contorted. ------------------------------------------------------------ -- bjorn.gimle@online.dextel.se +46-8-7428086 -- -- bjorn@tt-tech.se +46-8-59095739 -- --(bjorn.gimle@duesenberg.se) 59.22371 N, 18.22857 E -- ------------------------------------------------------------ ************ Sent via DN Online (Sweden) UUCP Gateway **************