Re: Another NanoSail-D flare

From: Djlaszlo (
Date: Thu Feb 24 2011 - 15:49:00 UTC

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    I was clouded out on Feb 24 UT for this pass:
    MST UT minus 7 h  23 Feb  mag2.1  19:23:0510N  19:27:2346  ENE  
    19:27:2346  ENE
      but another Colorado observer, Michael Hotka saw passes of NanoSail-D 
    with a flare to mag +2.  He is an experienced amateur and observed from 
    Broomfield CO.
    from google latitude longitude altitude
    decimal 39.930555 -105.086896
    deg-min-sec 39° 55' 49.998" -105° 5' 12.8256"
    He reported:
    On my second attempt
    to see this satellite, I too had success. Tonight's pass was well 
    placed where
    the satellite passed by some bright stars I could find from my 
    backyard. I sat
    on the brighter bowl star of the little dipper and waited. At the 
    time, the satellite passed thru the FOV of my mounted 20x80 binocs. 
    When I first
    picked it up, it was maybe 4th magnitude and moving real fast. Must be 
    in a
    lower Earth orbit. I followed it to the top of its path as predicted by
    Heavens-Above. In this region, it brightened twice, to about 2nd 
    magnitude, for
    3-4 seconds each time. At the appointed time and place in the sky, the 
    disappeared into the Earth's shadow. This was a very cool, very dim and 
    moving satellite. I would recommend others see it
    Did Mike see any flickering?
    ...The first flare was a bit brighter than the second. The first 
    happened right near tail of Draco.
    The second happened about 10-20 seconds later, near the bowl stars of 
    the big
    dipper. It was noticably not as bright as the first and a bit shorter 
    duration. The satellite did not appear to be tumbling though. It was 
    brightness until it flared and returned to the previous brightness. I 
    watched it
    until it disappeared into the shadow of the Earth.
    I did not notice any fluctuations in brightness for most of the pass of 
    satellite. It was pretty constant. The first flare resembled an Iridium 
    but it seemed to have two stages of brightness. It brightened 
    like an Iridium satellite does, held that brightness for a second or so 
    and then
    brightened just a bit more for the last couple of seconds and then 
    dimmed very
    quickly to the constant brightness of about 1/2 as bright (to what it 
    was before
    it flared and what it was for most of the pass). The second flare was 
    as bright
    as the first flare's initial brightening.
    It did seem dimmer a few seconds before it entered the Earth's shadow 
    This could have been due to thicker clouds overhead. I had a thin cloud 
    deck in
    the north and was able to see Polaris, the two bowl stars of the little 
    barely saw the tail star of Draco and just the main stars of the big 
    Barely able to see 3rd magnitude stars with my unaided eye.
    Hope this helps.
    Michael Hotka
    Amateur Astronomer
    Deep Sky Marine
    JPL Solar System Ambassador
    My Homepage:
    Did you see ANY fluctuation in brightness?  I thought I had some 
    flickering the night before, but it was subtle and I did
    not mention it in my report.  I was thinking maybe an artifact of 
    passage into shadow.  But I saw this today in the Spaceweather gallery 
    from Peter Rosen:
    I photographed NanoSail-D from Stockholm, Sweden, on Feb. 4th. The sail 
    was very
    low on the horizon, but I was able to catch it using my Canon EOS 5D 
    camera. I estimate its magnitude between +6 and +7.  There are many 
    other satellites in the field of view and some airplanes coming in for 
    landing at the local airport.
    NanoSail-D behaves very differently from
    other satellites as its visibility seems to pulsate in short flashes 
    several per second. This image zooms in on the phenomenon. I wonder if 
    it due to
    small changes in the sail's direction and thus reflectivity?
    -----Original Message-----
    From: Arto Oksanen <>
    Sent: Wed, Feb 23, 2011 1:07 pm
    Subject: Another NanoSail-D flare
    I imaged another NanoSail-D flare from Nyrölä, Finland (62.3N, 
    25.5E).The satellite flared right at the end of a long overhead pass at 
    16:38UT today Feb 22, 2011.  The image was taken with Canon EOS 350D 
    +Samyang 8 mm fisheye f3.5, exposure time 30 
    .jpgarto-- Arto Oksanenarto.oksanen@jklsirius.fiMuurame, 
    Finland_______________________________________________Seesat-l mailing 
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