5919 Possible obs of #14139 2009-04-18

From: Bjoern Gimle@GlocalNet (Gimle@GlocalNet)
Date: Sun Apr 19 2009 - 08:58:51 UTC

  • Next message: David Brierley: "DMB Obs April 18 a.m."

    I failed a few times to observe KH-9 Elint #14139 within "expected" interval
    (+- 3 min) from "current" elset epoch 07163.
    (1 14139U 83060C   07163.64774262 0.00000023  00000-0  83610-4 0    00)
    
    I decided to produce an elset by fitting this to synthetic observations
    2005-2007, and forwarding it to current date with Vec2TLE.
    This reduced B* and ndot2 by about 60%, resulting in passes 7 min later.
    With five "obs" the spread of the residuals was about +-15s when
    changing only mean anomaly, mean motion, B*.
    With three obs, omitting 2005, the spread was six times smaller
    (actually mainly cross-track). But the difference in pass prediction 2009
    was only 45s, so I decided I should trust it, and use the telescope.
    
    I had difficulty finding the target area manually (I had not yet
    repaired the torn battery cable), and started observing less than
    a minute before expected pass time.
    Only 38s after that time a mag 8 object passed at the predicted
    place and direction. Predictions from all Mike+SpaceTrack elsets
    showed an Ariane debris object (#17155) on a very similar track,
    but it should pass 58s later on a two-day old low-drag elset (and I
    double-checked that I didn't make a one minute read-out or
    calculation error).
    
    Obs - Pred: 0.250 deg X-track; 37.985 s late, relative 1.02 day old elset:
    1 14139U 83060C   09107.86826340  .00000009  00000-0  34441-4 0    01
    2 14139  96.6588 212.0160 0001785 149.6517 211.5019 12.93744202    01
    
    14139 83 060C   5919 E 20090418211433000 38 25 1551972+160711 19 S
    24680 96 072A   5919 E 20090418200848800 17 25 0513465+371419 18 S
    24680 96 072A   5919 E 20090418200729470 17 25 0644493+251714 68 S
    24680 96 072A   5919 E 20090418200721040 17 25 0653003+234445 38 S
    24680 96 072A   5919 E 20090418200706600 17 25 0706802+205255 58 S
    
    
    Observations are, as I always do, reported in IOD format:
    http://www.satobs.org/position/IODformat.html
    Equipment: Stopwatch 100 (80) lap times, speaking clock 1ms accuracy over phone
    Cheap binocular 10 (7)x 50, Meade LXD-55 SN-8" f/4, usually at 25 x
    -- Björn Gimle                                            --
    -- COSPAR 5917, STAR,  +18.05447 (E), +59.34185 (N), 33 m --
    -- COSPAR 5918 WGS84,  +18.10127 (E), +59.29813 (N), 44 m --
    -- COSPAR 5919, MALMA, +18.6206  (E), +59.2615  (N), 33 m -- 
    
    
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