quadruple glint from an Iridium

From: Walter Nissen (wnissen@freenet.tlh.fl.us)
Date: Sun Mar 25 2001 - 10:21:07 PST

  • Next message: Skywise: "Re: mir hrd last week"

    rodsladen@crosswinds.net ("Rod Sladen") writes:
    
    > 1. Double flares may actually be fairly common, but are missed ...
    > Only if checking timings or positions carefully is is evident that the
    > flare is not symmetric about the predicted flare maximum time.
    
    Following up my earlier message referencing
    http://www2.satellite.eu.org/seesat/Jul-1998/0367.html and
    http://www2.satellite.eu.org/seesat/Sep-1998/0013.html
    :
    
    I ran an old version of IRIDFLAR, reaching deep into the realm of
    faintness, and this is what it generated for 2001-03-23, only a few
    hours prior to the ditching of the Mir Complex:
    
                          Iridium Coordinates  Range   Sat   Solar
    Peak  Std    Maximum Flare
    Ir   Date      Time    Azm El   RA   Decl  (km)  N Ill Azm  Elev M FlrAng
    Mag  Mag  Mag Latitude Longitude
    53  1- 3-23  1:13:45.0 110 41 10h58  13.7 1125.7 D Lit 288 -17.2 R  8.33
    4.6 -8.0  4.3  41.0754  -79.3979
    84  1- 3-23  1:22:48.2 115 50 10h29  17.5  987.3 D Lit 289 -18.8 R  0.48
    -3.3 -8.2 -3.3  41.3607  -81.7416
     9  1- 3-23  1:31:55.0 127 60  9h48  20.1  889.9 D Lit 291 -20.4 R  9.45
    4.5 -8.4  4.6  41.4335  -83.9921
    
    which I reformatted to be consistent with my archaic version of
    QuickSat:
    
           1 13 45   ?  41 110     D  4.6     1125 1058  13.7  Iridium 53
           1 22 48   ?  50 115     D -3.3      987 1029  17.5  Iridium 84
           1 31 55   ?  60 127     D  4.5      889  948  20.1  Iridium  9
    
    I then consulted my table of the Iridia which shows the order in which
    they pass over in the successive planes.
    
    I was then able to make the following OBS:
    
    Ir P47 50/53 not seen
    
    Ir P48 56    mag 6 or 7 A Denebola         20010323  055
                 difficult to see
    
    Ir P49 52/50 located mag 5 or 6 A Denebola 20010323  10420?
                 glint mag 5?                  20010323  10545.84
                 lost mag 7?                   20010323  10555.40
    
    Ir P4A 53/54 located mag 6?                20010323  11218.55
                 up to mag 5?                  20010323  11252.02
                 glint mag 4 or 5              20010323  11332.76
                 glint mag 4?                  20010323  11359.50
                 glint mag 4 or 5              20010323  11431.30
                 glint mag 4?                  20010323  11456.30
                 down to mag 5?                20010323  115 4
                 lost mag 7?                   20010323  115 8.51
    
    Ir P40 84    located mag 6?                20010323  12116.58
                 up to mag 5?                  20010323  122 9.89
                 glint mag -4?? naked eye      20010323  12249.30
                 down to mag 5?                20010323  12344.03
                 glint mag 4?                  20010323  124 7.74
                 down to mag 5?                20010323  124 9.80
                 lost mag 7?                   20010323  12414.02
    
    EOO
    
    As usual, personal equation, estimated to be .25 seconds, is not
    applied, UTC and CE are used, use of 7x35 binocs is not noted, and
    since I use UTC comprehensively, no village-idiot time is provided.
    
    As has been the case in the past when high-multiplicity glints were
    observed, the dips and peaks were quite shallow, demanding close
    attention.  The asymmetries, with respect both to the predicted times
    and the observed instants of mag 5, should be evident.
    
    Iridial glints produce narrow North-South tracks.  It would be
    interesting to see if two or more observers could verify the
    asymmetries.
    
    Also, note that the prediction for the quadruple glint would not have
    been generated by a search less deep than mag 5 or so.  I look for mag
    6, and then expand from that.  I see a lot more that way.
    
    I hope you see a lot more, too, and will let us know about it.
    
    Cheers.
    
    Walter Nissen                   wnissen@tfn.net
    -81.8637, 41.3735, 256m elevation
    
    ---
    
    Take Back the Diamond-Studded Velvet:
    Support your local dark sky:  http://www.darksky.org
    
    ---
    
    Iridium 52       4.0  1.8  0.0  6.0 d  8.4
    1 25169U 98010A   01076.15698527 -.00000453  00000-0 -16898-3 0  4116
    2 25169  86.3982 310.8210 0002503  82.6689 277.4796 14.34214968160961
    Iridium 56       4.0  1.8  0.0  6.0 d   11
    1 25170U 98010B   01073.70874618 +.00000085 +00000-0 +23327-4 0 01542
    2 25170 086.3968 311.8246 0002540 078.2604 281.9039 14.34218276160591
    Iridium 50       4.0  1.8  0.0  6.0 d  9.2
    1 25172U 98010D   01076.77221399 -.00000021  00000-0 -14509-4 0  4071
    2 25172  86.3965 310.5434 0002515  68.6575 291.4854 14.34217639161030
    Iridium 53       4.0  1.8  0.0  6.0 d  9.4
    1 25173U 98010E   01076.16332575  .00000075  00000-0  19870-4 0  3997
    2 25173  86.3967 310.8010 0002582  78.2148 281.9327 14.34218525160957
    Iridium 84       4.0  1.8  0.0  6.0 d  6.9
    1 25530U 98066D   01077.14642667  .00000133  00000-0  40415-4 0  1947
    2 25530  86.4017 310.3411 0001768  34.3630 325.7679 14.34218707126327
    
    
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