Re: tips search

From: Edward S Light (
Date: Mon Jul 07 2003 - 11:09:35 EDT

  • Next message: Michael McCants: "Re: TiPS search"

    This morning, "Kevin Fetter" <> wrote:
    > Subject: tips search
    > This morning I did a seach for tips
    > I saw something that seems to match the direction that tips would travel. It
    > was 9 - 10 minutes ahead of where tips was to pass based on it old orbit. So
    > either it was that early are I saw something else. All I saw was a point of
    > light, no tether. I was using my 10*50 binculars and so the tether could have
    > been to faint to see.
    > So do a search at least 10 minutes ahead of time, in the fluke chance it was
    > tips I saw and it's passing by that early.
    If one assumes that this morning (e.g. day 188.333), TiPS was 9.5 minutes
    ahead of the latest "real" TLE, viz.
    1 23937U 96029F   03113.02889112 0.00001900  00000-0  17481-2 0    05
    2 23937  63.4145   5.2674 0231000   0.3215 359.6785 13.71273610    04
    what's the best way to derive search elements? A 9.5 minute difference
    corresponds to about 0.0905 revolutions, and over 75.304 days would
    represent an increase in the average mean motion of .001201353 rev/day.
    It seems to me that leaving everything along except for the TLE epoch
    might cause problems with the angular-positional elements. If one were
    to adjust the decay term (M2) leaving the epoch and initial mean motion
    unchanged, wouldn't the B* term also need adjustment? - and it's not
    obvious to me how to do that.
    If one changes ONLY the initial mean motion, one gets the TLE:
    TiPS -9.5min
    1 33937U 96029F   03113.02889112 0.00001900  00000-0  17481-2 0    06
    2 33937  63.4145   5.2674 0231000   0.3215 359.6785 13.71393745    07
    This "adjusted" TLE would, for my location, produce a pass tomorrow
    morning culminating at 03:42.8 EDT (07:42.8 UTC) at alt/azim 47/242
    compared to the "old real" TLE at 03:52.7 EDT (07:52.7 UTC) at 40/243.
    I'll try looking for that [those] pass[es] in the morning, but would
    welcome more reasoned suggestions from the skilled celestial mechanicians
    on this List.
    Clear and dark skies!
       Ed Light
    N 40.1075, W 074.2312, +24m
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