Raduga 27 is accelerating again

From: Jason P Hatton (jason.hatton@wanadoo.fr)
Date: Mon Feb 21 2000 - 20:42:24 PST

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    Hello everyone,
    		Thanks to good weather I've been able to observe the bright geoflasher
    Raduga 27 (91-014A/21132) regularly during the last few weeks. After a
    several months of a deceleration the flash period now appears to be
    accelerating again. Here are my observations in PPAS format;
    
    Decelerating period....
    Observing from Approx. 52.7N, 2W, 180M)
    91- 14 A 99-12-25 19:31      JPH 737.0 1.0   8 92.1   F'F' vm mag+7->inv
    91- 14 A 99-12-28 18:20      JPH1304.9 0.2  14 93.21  A'A' mag+6->inv
    91- 14 A 00-01-01 18:04      JPH1136.8 0.5  12 94.73  A'A' mag+6->inv
    >From 43.692N, 7.246E,30M
    91- 14 A 00-01-23 18:16      JPH1412.2 0.2  14 100.87 F'F' mag+6->inv
    Acceleration starts....
    91- 14 A 00-02-04 21:21:09.1 JPH1836.4 0.2  18 102.02 A'A' vm
    mag+8/10->inv
    91- 14 A 00-02-09 20:42:55.3 JPH1325.3 0.2  13 101.95 A'A' mag+8->inv
    91- 14 A 00-02-10 20:22:04.4 JPH2445.1 0.2  24 101.88 A'A' mag+8->inv
    91- 14 A 00-02-12 20:25:09.9 JPH2542.9 0.2  25 101.72 A'A'
    mag+8/+11->inv
    91- 14 A 00-02-13 03:12:53.6 JPH2746.5 0.2  27 101.72 A'A' mag+6/+9->inv
    91- 14 A 00-02-13 19:40:56.9 JPH2337.4 0.2  23 101.63 A'A' mag+8->inv
    91- 14 A 00-02-16 19:43:42.2 JPH 810.6 0.2   8 101.33 A'A' mag+9->inv
    91- 14 A 00-02-17 19:30:29.8 JPH2024.4 0.2  20 101.22 A'A' mag+8->inv
    91- 14 A 00-02-19 18:34:31.5 JPH1994.8 0.2  20 100.88  A'A' mag+8->inv
    
    The flashes are only visible during a period of approximately 80
    minutes, with the period of visibility starting approximately 12 minutes
    earlier each day; 
    13-Feb-2000
    1st flash seen = 19:02UT, last flash = 20:20UT
    16-Feb-2000
    last flash = 19:44UT
    17-Feb-2000
    last flash = 19:32UT
    The flashes are intially visible at approx mag+10, brighten to mag+8 in
    the middle of the zone of flash visibility before fading away again.
    
    Question: Can these data be used to determine the rotation axis of
    satellite & is there anyone on the list who knows how to make the
    calculations? 
    
    Interestingly, a second series of flashes are visible in the early
    morning, which can be as bright as mag +6 (eg. 13-Feb morning
    observation). A quick glance at my Skymap finder charts suggests the
    period of flash visibility may correlate with the declination of the
    satellite. Raduga 27 is in a 5 degree inclination & so appears to drift
    north then south during the day. The evening flashes occur when the
    satellite is drifting northwards, whilst the morning flashes occur when
    the satellite passes through a similar declination on its way south.
    Additionally, the flashes observed in December & January might
    consititute a third series of flashes, given the period of visibility of
    the current "evening" flash series.
    
    All in all quite an interesting object to observe!
    
    Here is a recent element for Raduga 27:
    Raduga 27   
    1 21132U 91014A   00046.71327620 +.00000120 +00000-0 +00000-0 0 02943
    2 21132 005.6418 065.9041 0005312 202.4570 157.6642 01.00311841032860
    
    
    Best wishes & Clear skies,
    
    
    Jason 
    
    Jason P Hatton
    06200 Nice
    France
    
    43.692N, 7.246E,30M
    (43d41'29"N,7d14'47"E,30m)
    
    http://www.geocities.com/CapeCanaveral/Hangar/1668/high-alt.htm
    
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