Re: Nanosail-D flash pattern, and images of yesterday

From: alain.figer@club-internet.fr
Date: Wed Aug 17 2011 - 11:49:10 UTC

  • Next message: Scott Tilley: "ST Obs Aug 17th"

    Hi Marco,
    Last night I took a series of  6 consecutive photos in a field in Aquila. All photos were of 4 sec duration.
    In all the photos, a same flashpattern seems rather obvious : 1 bright maximum followed by 2 secondary maxima. At times both secondary maxima merge together. The brightest flash is very sharp and also variable in magnitude. It can be at times definitely fainter. I derived a photometric period of  0.73 sec, respectively : 0.727 ; 0.729 ; 0.728 ; 0.723 for the 4 photos with a complete 4-sec track.
     
    See for instance these 3 consecutive images - separated by about 1 second - here :
    http://www.flickr.com/photos/25296169@N07/6052688746/in/photostream
    http://www.flickr.com/photos/25296169@N07/6052161681/in/photostream/
    http://www.flickr.com/photos/25296169@N07/6052731802/in/photostream/
     
    They are enlargements of a small part in the original photos. The original photos cover the same larger part of the sky. 
    Regards
     
    Alain Figer
    48.67 N
     2.13 E 
    170m ASL
     
    
    
    ========================================
    
    Message du : 15/08/2011
    De : "Marco Langbroek " <marco.langbroek@wanadoo.nl>
    A : "satelliet lijst (SeeSat)" <SeeSat-L@satobs.org>
    Copie à : bram.dorreman@skynet.be, ralf.vandebergh@home.nl
    Sujet : Nanosail-D flash pattern, and images of yesterday
    
    
    
    Hi all,
    
    For those interested:
    
    Widefield images of yesterday evening's fine Nanosail-D (10-062L) pass and a 
    brightness variation curve derived from one of these images, have been posted here:
    
    http://sattrackcam.blogspot.com/2011/08/nanosail-d-flashing-rapidly-and.html
    
    Flash timings from the image in question:
    
    image s14082011_9
    14 Aug 2011, 20:51:17.30 - 20:51:27.35 UTC
    
    flash times (UTC):
    20:51:17.39
    20:51:17.89
    20:51:18.15
    20:51:18.42
    20:51:18.90
    20:51:19.17
    20:51:19.63
    20:51:20.40
    20:51:20.83
    20:51:21.14
    20:51:21.40
    20:51:21.88
    20:51:22.13
    20:51:22.62
    20:51:22.86
    20:51:23.32
    20:51:23.79
    20:51:24.06
    20:51:24.35
    20:51:24.81
    20:51:25.49
    20:51:25.72
    20:51:26.22
    20:51:26.63
    20:51:26.91
    20:51:27.17
    
    The other images were too saturated (trail too bright).
    
    Flash interval is wildly variable, between 0.23-0.77 seconds, with an average 
    0.39 +- 0.14 seconds.
    
    The curve from this image is quite nice, with sharp peaks.
    
    - Marco
    
    
    -----
    Dr Marco Langbroek - SatTrackCam Leiden, the Netherlands.
    e-mail: sattrackcam@wanadoo.nl
    
    Cospar 4353 (Leiden): 52.15412 N, 4.49081 E (WGS84), +0 m ASL
    Cospar 4354 (De Wilck): 52.11685 N, 4.56016 E (WGS84), -2 m ASL
    SatTrackCam: http://home.wanadoo.nl/marco.langbroek/satcam.html
    Station (b)log: http://sattrackcam.blogspot.com
    -----
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