Re: Water/fuel dumps magnitude

From: Larry Wood (
Date: Thu Apr 07 2005 - 18:16:16 EDT

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    Oscar A. Rodriguez / PMEE-Space wrote:
    > Thanks for the info, Kevin.
    > I'm very interested in watching fuel/water dumps, but I don't know the 
    > maximum magnitud they can reach. Are they naked-eye visible?
    I witnessed a fuel dump some years ago. Here is an article one of our members 
    (Bruce McCurdy) posted to a local newsgroup. I have done a bit of editing to omit 
    some redundant info and correct a couple of minor errors.
    Larry Wood
        We saw something like this from the Observatory at Edmonton Space &
    Science Centre's a few years ago, a diffuse glow not dissimilar from the
    Andromeda Galaxy which was by coincidence only a few degrees away from M31
    itself. One of our members (Larry Wood) was actually trying to spot the
    galaxy naked-eye -- which can only be done from that urban site on the very
    best of nights -- and found this rather brighter patch instead. I suspect
    Larry spotted it fairly early in its development. Between Observatory
    volunteers, a few members of the public and judicious use of the telephone,
    within a few minutes a whole bunch of us were watching this "cloud" very
    gradually drift against the sky over a period of many minutes. Slow enough
    that the drift of the stars had to be factored in to any calculation of the
    object's actual position in 3D space.
      It was slightly cone-shaped -- more like a chevron with linear lines eminating 
    from both sides of the center satellite track at about a 70 angle. The cloud was 
    about 3 times longer than its width. The brightish stellar nucleus (~ magnitude 
    10)just ahead of the focus. I followed the satellite for about 45 minutes in the 
    14" SCT. When first seen the satellite was at about 10,000 km alt and when last 
    seen it was at about 16,000 km alt and ~ magnitude 12.5.
    Later as the contrail dissipated into larger and fainter the fuel dump
    explanation was postulated. Upon further investigation we found it
    corresponded with the launch of a spy satellite a short time earlier
    from Vanderburg AFB into a highly inclined Molniya orbit, with an apogee that does 
    not precess but stays put over a very specific -- and presumably strategic ---
    spot.This was just 4 days before the USA moved on Iraq. The satellite had a 
    717.8-minute orbit, almost exactly half of a sidereal day. So from our perspective 
    at +53.6 N., this thing was still going pretty much straight up when it dumped 
    its unneeded fuel. A bizarre observation which I remember clearly years later.
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