Last updated 9-Nov-1999
Someone "scooped" us on SH4's 1999 recovery by three days (thanks!). Looks like the link to 1991 sighting was broken, so instead of four oppositions, we're back to three.
1998 SH4 Epoch 1999 Aug. 10.0 TT = JDT 2451400.5 Williams M 149.61490 (2000.0) P Q n 0.17317532 Peri. 107.86573 -0.41729464 +0.90840817 a 3.1877093 Node 137.44108 -0.84749964 -0.37880148 e 0.1231950 Incl. 2.17648 -0.32803892 -0.17692945 P 5.69 H 13.8 G 0.15 U 4 From 27 observations at 3 oppositions, 1996-1999, mean residual 0".55. Last observed on 1999 Nov. 4. Elements from MPEC 1999-V19.
In the August MPC status report, it appears another opposition observation was found for 1999 SH4:
1998 SH4 Epoch 1999 Aug. 10.0 TT = JDT 2451400.5 Spahr M 149.85966 (2000.0) P Q n 0.17319594 Peri. 107.62515 -0.42096109 +0.90671476 a 3.1874563 Node 137.45017 -0.84596866 -0.38222290 e 0.1232388 Incl. 2.17740 -0.32730534 -0.17825264 P 5.69 H 13.8 G 0.15 U 4 From 24 observations at 3 oppositions, 1991-1998, mean residual 0".60. Orbital elements from MPC 35716.
After 10-Oct-1998 (UT) observations:
1998 SH4 Epoch 1999 Jan. 22.0 TT = JDT 2451200.5 Williams M 114.99876 (2000.0) P Q n 0.17270732 Peri. 107.96506 -0.41428770 +0.90978400 a 3.1934655 Node 137.53124 -0.84876711 -0.37601444 e 0.1207542 Incl. 2.17856 -0.32857281 -0.17580163 P 5.71 H 14.0 G 0.15 U 6 From 20 observations at 2 oppositions, 1991-1998, mean residual 0".59. Orbital elements from MPEC 1998-T22.
1998 SH4 Epoch 1998 July 6.0 TT = JDT 2451000.5 Williams M 81.38249 (2000.0) P Q n 0.17282598 Peri. 107.32168 -0.42437897 +0.90512070 a 3.1920036 Node 137.53746 -0.84453760 -0.38543007 e 0.1184406 Incl. 2.17920 -0.32658647 -0.17944406 P 5.70 H 13.5 G 0.15 U 6 From 19 observations at 2 oppositions, 1991-1998, mean residual 0".76. Orbital elements from MPEC 1998-S43.
1998 SH4 Epoch 1998 Sept. 4.0 TT = JDT 2451060.5 Williams M 84.00403 (2000.0) P Q n 0.17215754 Peri. 117.21365 -0.27541087 +0.96099181 a 3.2002607 Node 136.77494 -0.89458546 -0.24653961 e 0.1041104 Incl. 2.12285 -0.35194559 -0.12535132 P 5.73 H 14.0 G 0.15 From 9 observations 1998 Sept. 19-23. E-assumed. Orbital elements from MPEC 1998-S25.
Elements courtesy of the
MPC .
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