DM-F3 / Delta 3 RB - Who is Who ?

From: Ron Lee (
Date: Mon Aug 28 2000 - 09:05:04 PDT

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    Around 10:30 UT on 28 August 2000 both objects from this launch
    made a pass where each would be visible at the same time in the
    field of view of my 8" telescope.  The elsets used and NORAD 
    numbers are those currently used by USSPACECOM.  Unresolved at
    this point is whether the identity is incorrect.  Elsets used
    at the end of this message.
    At about 10:32 UT #26476 (rocket?) came in at the top of the
    field of view.  It was around magnitude 10 and seemed steady
    in brightness.  Soon thereafter the supposed payload (#26475)
    cam in a little lower.  It was 0.5 to 1.0 magnitudes brighter
    than #26476.  Soon a cloud intervened so I had to reposition
    to a point farther east.
    About 10:49 UT #26476 comes into the field of view.  I tracked
    for a bit and may have seen a slight fluctuation.  #26475 was
    then picked up and a new pattern emerged.  It remained a near
    constant brightness for a lengthy time then dimmed for a few
    seconds, followed by a sharp flash, another dimming for a few 
    seconds then back to the normal brightness.  The flash allowed
    more accurate timing of the period which I recorded at 40.4
    seconds (+/- 0.2 sec). The faint period was to invisibility.
    I normally don't pay much attention to the n-dot term but this
    analysis by Harro makes sense to me.  The apogee of the "payload"
    object (#26475) is decreasing with each new elset.
    These objects make at evening pass for the USA that others may wish
    to observe to confirm my obs.  I am certain of the period of the
    object #26475.  Still at question is whether #26476 exhibits some
    variation in brightness.  If it does, it is subtle unlike the obvious
    change in brightness of #26475.
    DM-F3                                            20618 x 188 km
    1 26475U 00048A   00240.36785801  .00111621  67413-6  26363-2 0   116
    2 26475  27.6330 308.9746 6087038 177.5210 188.1665  3.99400636   150
    DM-F3 Delta 3 r                                  20637 x 186 km
    1 26476U 00048B   00239.11586436  .00003254  77957-6  84746-4 0    73
    2 26476  27.6082 309.1530 6090299 176.5940 191.2062  3.99105841   102
    Ron Lee
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