Current observations

at 476 Grange Observatory




In February 2001 we all have heard about the NEAR spacecraft successful landing on the (433) Eros asteroid after entering in orbit around it (check NASA News);
Grange Obs. is proud to have contributed to JPL for the refinement of that Solar System's minor body orbital elements (update of the DE405 planetary model), having extensively observed he asteroid during its 1995-1996 favourable appearance:
Observations by Grange Obs.
Newton 0.3 m f/4 + CCD + red filter, GSC reference stars (J2000).

00433         C1995 09 14.89861 00 00 55.14 +25 01 24.3                      476                      
00433         C1995 09 14.90521 00 00 54.46 +25 01 27.0                      476
00433         C1995 09 14.90868 00 00 54.06 +25 01 28.6                      476
00433         C1995 09 14.91319 00 00 53.59 +25 01 31.1                      476
00433         C1995 09 14.91875 00 00 53.02 +25 01 33.2                      476
00433         C1995 10 01.97396 23 28 25.19 +25 42 10.6                      476
00433         C1995 10 01.98333 23 28 24.02 +25 42 09.6                      476
00433         C1995 10 01.98924 23 28 23.26 +25 42 09.0                      476
00433         C1995 11 14.87882 22 52 07.18 +19 27 01.8                      476
00433         C1995 11 14.88368 22 52 07.32 +19 26 59.2                      476
00433         C1995 11 14.88785 22 52 07.46 +19 26 57.7                      476
00433         C1995 11 14.89931 22 52 07.81 +19 26 52.2                      476
00433         C1995 12 17.83438 23 37 49.97 +17 39 28.0                      476
00433         C1995 12 17.83924 23 37 50.51 +17 39 28.5                      476
00433         C1995 12 17.84583 23 37 51.37 +17 39 29.0                      476
00433         C1996 01 18.83177 01 00 29.27 +19 28 47.8                      476
00433         C1996 01 18.83646 01 00 30.12 +19 28 49.0                      476
00433         C1996 02 14.85938 02 31 29.93 +21 29 49.6                      476
00433         C1996 02 14.86927 02 31 32.08 +21 29 51.9                      476
00433         C1996 02 14.87379 02 31 33.03 +21 29 52.7                      476
00433         C1996 02 14.88212 02 31 34.88 +21 29 54.1                      476
00433         C1996 02 14.88941 02 31 36.45 +21 29 55.2                      476
00433         C1996 03 11.82726 04 11 41.24 +21 40 06.9                      476
00433         C1996 03 11.84306 04 11 45.03 +21 40 03.9                      476
00433         C1996 04 15.86979 06 31 28.95 +17 06 15.0                      476
00433         C1996 04 15.87517 06 31 30.21 +17 06 10.9                      476
00433         C1996 04 15.88663 06 31 32.86 +17 06 02.2                      476

Total of 27 observations.
During that period the following pictures have been taken, showing the asteroid's motion:




The asteroid Eros in 1995, shining at 13 magnitude.

Using the above measurements, covering a significant amount of time, the following keplerian orbital elements were calculated:
(433) Eros
   Perihelion 1999 Sep 20.409410 TT
Epoch 2000 Feb 26.0 TT = JDT 2451600.5
M  88.75617              (2000.0)            P               Q
n   0.55965596     Peri.  178.64386     -0.54587846     -0.82340557
a   1.4583283      Node   304.41709      0.76694605     -0.41657327
e   0.2227764      Incl.   10.82860      0.33735806     -0.38531801
P   1.76      q 1.1334472
From 27 observations at Grange Obs. 1995 Sep. 14-1996 Apr. 15;   RMS error 0.591 arcseconds

which have to be compared with the elements calculated by Dr. Gareth Williams at the time and herein reported:
  (433) Eros
Epoch 2000 Feb. 26.0 TT = JDT 2451600.5  (M-N)          Williams
M  88.75095              (2000.0)            P               Q
n   0.55964439     Peri.  178.64814     -0.54589653     -0.82339289
a   1.4583484      Node   304.41411     +0.76694093     -0.41659247
e   0.2227670      Incl.   10.82848     +0.33734047     -0.38532437
P   1.76           H   11.16          G   0.46
From 2402 observations at 42 oppositions, 1893-1993, mean residual 0".72.

The current (433) Eros orbital elements are regularly published by MPC Minor Planet Center


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