Hi,
I have made some post-T measurements in STEREO COR2B images as:
CK11W030 S2011 12 16.49653 10 23 13.16 +09 18 09.8 1.16N C50
CK11W030 s2011 12 16.49653 2 +0.87787017 -1.31083013 -0.56839765 C50
CK11W030 S2011 12 16.51736 10 23 00.84 +09 16 28.3 1.94N C50
CK11W030 s2011 12 16.51736 2 +0.87836675 -1.31057816 -0.56828664 C50
CK11W030 S2011 12 16.52778 10 22 55.96 +09 15 43.0 1.83N C50
CK11W030 s2011 12 16.52778 2 +0.87861483 -1.31045245 -0.56823114 C50
CK11W030 S2011 12 16.53819 10 22 49.10 +09 15 06.5 2.13N C50
CK11W030 s2011 12 16.53819 2 +0.87886267 -1.31032686 -0.56817562 C50
CK11W030 S2011 12 16.55903 10 22 37.50 +09 13 18.1 2.04N C50
CK11W030 s2011 12 16.55903 2 +0.87935949 -1.31007477 -0.56806442 C50
CK11W030 S2011 12 16.56944 10 22 33.01 +09 12 39.6 1.02N C50
CK11W030 s2011 12 16.56944 2 +0.87960733 -1.30994851 -0.56800884 C50
and got these orbital elements with FindOrb:
C/2011 W3
Perihelion 2011 Dec 16.009802 TT = 0:14:06 (JD 2455911.509802)
Epoch 2011 Dec 17.0 TT = JDT 2455912.5 Earth MOID: 0.5748
M 0.00118 (2000.0) P Q
n 0.00119392 Peri. 53.49452 0.18412433 -0.89952644
a 88.0005673 Node 326.36415 -0.96013504 -0.07835177
e 0.9999368 Incl. 134.33872 0.21033051 0.42978270
P 825.52 M(N) 16.5 K 10.0 q 831960.383km Q 175.995573
From 115 observations 2011 Nov. 27-Dec. 16; RMS error 3.839 arcseconds
The orbital period (here ~825 years) seems to be quite reasonable.
Regards, Rainer