Fw: Lacrosse 5: analysis of brightness

From: Bruce MacDonald (macdonalddevizes@tiscali.co.uk)
Date: Sun Oct 23 2005 - 04:26:12 EDT

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    >
    > Ted Molczan wrote:
    > > Lacrosse 5's std mag of 2.9 in its final configuration, does represent a
    > > significant increase in apparent brightness - about 0.7 magnitudes -
    > relative
    > > its predecessors. So far, Ed Cannon has responded to my question about
    > colour,
    > > agreeing with my observation that it is less red. Also, I note Thierry
    > Marais'
    > > argument in support of the idea that the difference colour may account
    for
    > much
    > > of the perceived difference in brightness.
    >
    > Instead of making a positional observation, I observed last night's pass
    of
    > Lacrosse 5 at 19:55 UTC with the naked eye.  Conditions here were good
    with
    > reasonable transparency and no moon.  Lacrosse 5  passed within a couple
    of
    > degrees of Vega (alpha Lyrae) which was very useful indeed for a visual
    > estimate of brightness and colour.
    >
    > I estimated its brightness to be between 1.5 and 2 on a maximum 62 degree
    > pass before shadow entry.  Its colour was noticeably more pale than its
    > predecessors - a yellow-white colour, definitely not orange.  I would
    > confirm that it is half a mag or more brighter than the other Lacrosse
    sats,
    > though I accept Thierry's point about perceived brightness.
    >
    > Best wishes
    >
    > Bruce
    >
    > Bruce MacDonald
    > COSPAR Site 2751
    > Devizes, Wiltshire, UK
    > 51.3440 N 1.9849 W 125m (WGS84)
    >
    
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