RE: New user, with a question-

From: Paul Grace (
Date: Wed Dec 03 2008 - 16:09:36 UTC

  • Next message: David Brierley: "DMB Obs December 3 a.m."

    Wow--Thank you both.
    Isn't wasn't a flare in that sense (the way iridium flares for example) it
    was a flash.
    It really must have been ETS-6, and it is very interesting to see how poorly
    my memory works--trying to reconstruct the view indoors with my star charts
    15 minutes later!
    Just what I need, another hobby!  (LOL!)
    Thanks all, and I have a bunch of learning to do.
    -----Original Message-----
    From: Bjoern Gimle@GlocalNet [] 
    Sent: Wednesday, December 03, 2008 2:46
    To: Paul Grace
    Subject: Re: New user, with a question-
    Hi Paul,
    welcome to the list. Your observation report is so detailed and well-worded
    that it surpasses many postings by long-time members! Just one detail:
    a "flaring" satellite indicates very slowly rotating, or not at all - you
    did use "flashing" initially.
    Ed's analysis is also so convincing that I didn't do one myself.
    I just verified the apparent tracks for you, using SkyMap.
    I enclose two projections, one in RA mode, which is true in siderial
    positions, and in angles/distances near declination zero (polar mode is too
    elongated far from the pole).
    The other one is stereographic in HORizontal mode, which is closest to
    natural proportions, and true on the alt/az grid, but track relative to
    stars is only accurate at the chosen time, 08:15 UTC.
    The latter image shows that the Glonass was moving WEST relative to the
    horizon, as Ed suggested, at position angle 25 degrees (1 o'clock).
    ETS 6 moved to 320 degrees ("10:40"), and would have entered Earth's
    penumbra around 08:35 at about 21380 km range, fully eclipsed around
    Glonass entered penumbra around 08:25 at about 20300 km range, fully
    eclipsed around 08:29:30.
    -- 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 --
    ----- Original Message -----
    From: "Paul Grace" <>
    To: <>
    Sent: Wednesday, December 03, 2008 7:57 AM
    Subject: New user, with a question-
    > Hello, my name is Paul Grace, I am a new subscriber to your list.  I'm an
    > amateur science buff, and have a rough knowledge of the night sky.  My
    > coefficient of geek is: I "predict" daytime iridium flares at the office
    > parking lot to fellow employees for the amusement value.  I have been
    > referred to this site as a resource that might be able to answer my
    > question-to wit:
    > I view the sky from a very unpolluted site, at 123.545W  38.956N UTC-8
    > Sunday Morning, 2008 Nov 30, 00:15 PST I was observing the sky with no
    > particular aim, and I noticed a bright flashing light about magnitude 3-4
    > on, for about 0.5 seconds, off a few seconds (5-6?), looking much like a
    > very high altitude aircraft strobe.  The light cycled like this several
    > times before I noticed that it was not moving against the stars.  The
    > flashes were somewhat irregular, sometimes missing a flash, sometimes the
    > flash was down near mag 7, only visible through my binoculars.  This
    > continued for perhaps 15 minutes, and then it stopped.  During the 15 
    > minute
    > period, I noticed the object was drifting slowly eastward against the 
    > stars,
    > and it seemed to be at the ecliptic, although I didn't have my telescope
    > available to determine its accurate position.  After, I went back inside I
    > estimated its location slightly above the ecliptic at about RA 3h 18m Dec
    > +01.78 best guess. (Azm 211, Alt 48.5)
    > I think I was observing a flare, from a Geostationary satellite.  Because 
    > it
    > was so bright, I think it must be a tumbling 3-axis sat, a spinner 
    > wouldn't
    > have large reflecting surfaces.  A LEO sat would not likely be illuminated
    > by the sun near midnight.
    > Is there a way to determine what bird it might be?  Is there a tumbling
    > 3-axis GEO satellite known in that region? (what would this be, 154 west
    > longitude?)
    > I thought it was pretty cool, my wife was impressed too!
    > Any comments would be appreciated, I'm a newbie here, so if this isn't the
    > proper forum, please be gentle...
    > Paul Grace
    > -------------------------------------------------------------------------
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