Ir's 71, 47, 27, 24/46, EORSATs, Mir, Resurs 1-4 r

Walter Nissen (dk058@cleveland.freenet.edu)
Sun, 26 Jul 1998 19:20:39 -0400 (EDT) 

OBS: 
 
Ir 71 was finally seen, presenting only a mildly unusual appearance.  I 
followed her for about a minute, mostly at mag 5 or 6, and really didn't 
see much to distinguish her from any ordinary operational object.  For a 
couple of seconds, recorded as 19980726 030549.25, she brightened a bit to 
mag 4.5 or 5.  Absent the present suspicion, probably not worth 
mentioning. 
 
Ir 47 mag -1?      glint        19980726  34109.7    mostly mag 5 or 6 
      dip to inv                19980726  34125.25   then mag 5 or 6 
 
Flat maxima, PPAS code: M, are quite difficult to judge. 
 
I was pleased to be joined by Victor Slabinski, distinguished orbital 
mechanician, for my observing session last evening.  Victor, observing 
Ir 47 naked eye, saw the glint as about 1.5 mags brighter than Arcturus. 
In any event, nothing like the predicted -6.7. 
 
We saw bright Resurs 1-4 r.  In the North, it once again displayed its 
tendency to begin displaying brief dips, and once again I detected 
sub-periods of differing length.  This time I recorded that the dips began 
very shallow and deepened, the object eventually becoming invisible during 
the dips. 
 
98- 43 G 98-07-26  3:14:39.4 WN   44.6 1.    3   14.86 __', Resurs 1-4 r, 
                        25400, initially S to well past C, then began 
                        brief dips, sub-periods 6.38s + 8.48s = 14.86s 
                        minima measured as much more precise than M maxima 
 
My log now shows: 
98- 43 G 98-07-12  3:41:29.5 WN   41.1 1.    5    8.2  __', Resurs 1-4 r, 
98- 43 G 98-07-24  4:01:52.8 WN   43.9  .8   3   14.64 __', Resurs 1-4 r, 
98- 43 G 98-07-26  3:14:39.4 WN   44.6 1.    3   14.86 __', Resurs 1-4 r, 
Has it been spinning down?  Or did it spin up between 980712 and 980724? 
 
Mir was excellent, but not as spectacular as 2 nights earlier, nor as the 
previous night when a low 31-degree altitude pass produced a mag -3 or -4 
glint, the brightest I've ever seen Mir, I think. 
 
C* 2335 reached mag 3?.  Does anyone else think the new EORSATs (also 
C* 2347) may be fainter than the previous? 
 
2335 
1 24670U 96069A   98204.18129500 -.00003043 +00000-0 -45282-4 0 09861 
2 24670 065.0354 106.5511 0010283 276.2498 083.7476 15.52034407091359 
2347 
1 25088U 97079A   98204.33672079  .00022009  00000-0  36443-3 0  3007 
2 25088  65.0219 178.2577 0012446 290.3977  69.5810 15.52108731 35087 
2359 
1 25376U 98039A   98204.58130405  .00133092  14297-4  21495-3 0   632 
2 25376  64.9093  56.8841 0051567  97.1814 263.5266 16.00684353  4495 
 
Is C* 2359 not an EORSAT? 
 
PPAS(beginning): 
81- 59 A 98-07-26  2:51: 4.8 WN   31.5  .6   8    3.93 NOAA 7 
97- 82 B 98-07-26  3:21:36.6 WN   30.6  .6   4    7.65 Iridium 24/46 = 25105 
97- 51 D 98-07-26  3:47:23.5 WN    7.6  .6   2    3.8  FF', Iridium 27 = 24947 
                                         4 flashes seen, mag 2?, -1?, 1?, and 3 
88-102 B 98-07-26  3:53      WN     .   .          .   lp, mag 6? -> mag 3 or 4 
                                                       C* 1980 r = 19650 
 
Cheers. 
 
Walter Nissen                   dk058@cleveland.freenet.edu 
-81.8637, 41.3735, 256m elevation 
 
--- 
 
We do not inherit this planet from our elders. We borrow her from our children. 
 
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Details: 
Latitude:  41.37350  Longitude:  -81.86370  Altitude:  256.0 m 
Time Zone: UTC  +0.0 h 
                      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 
47 98- 7-26  3:40:53.0 247 19 14h24  -3.4 1790.4 A Lit 331 -23.2 F  2.35  2.9 -6.7  1.3  40.7491  -81.5785 
47 98- 7-26  3:41:08.7 251 20 14h18  -0.4 1738.9 A Lit 331 -23.2 F  0.04 -6.7 -6.7 -8.3  41.3867  -81.8151 
47 98- 7-26  3:41:24.0 254 21 14h12   2.7 1693.7 A Lit 331 -23.2 F  2.45  2.9 -6.7  1.4  42.0236  -82.0083 
 
reformatted to conform to my one-line QuickSat output: 
       H  M  S  TIM AL AZI C   U  MAG SHD  RNG  R A   DEC 
       3 40 53   ?  19 247     A  2.9     1790 1424  -3.4  Iridium 47 -23 
25106  3 41 08   ?  20 251     A -6.7     1738 1418  -0.4  Iridium 47 -23!!!!! 
       3 41 24   ?  21 254     A  2.9     1693 1412   2.7  Iridium 47 -23 
 
For predictions, from molczan.tle: 
Iridium 47 
1 25106U 97082C   98204.14658374 -.00000031 +00000-0 -18030-4 0 01209 
2 25106 086.4002 260.2888 0001789 015.6826 344.4416 14.34216954030809 
 
Later elset, from Alan Pickup: 
Iridium 47       3.0  0.0  0.0  6.0 d            779 x 777 km 
1 25106U 97082C   98206.16987163 -.00000037  00000-0 -20363-4 0  1022 
2 25106  86.4000 259.4435 0001580  19.3424 340.7822 14.34216679 31095 
 
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P.S. 
For the benefit of people just starting to report observations, I might 
mention that you should not necessarily use my reports as examples for 
your own.  I am thinking particularly about my use of UTC.  People who 
haven't long since given up on VIT (village idiot time), haven't set their 
computers to UTC, don't have UTC on their wristwatches, aren't listening 
regularly to WWV, don't run predictions in UTC, don't log observed times 
in UTC, don't experience a nervous strain whenever asked to convert their 
precious UTC to VIT for public consumption, in other words, most people, 
should provide three pieces of information: 
 
the VIT for the OBS, 
the presumed conversion from VIT to UTC and 
the resulting UTC. 
 
Long experience has shown that people often make mistakes in this 
calculation, especially 1-hour mistakes, especially when shocked by the 
so-called (virtual?) change to or from daylight time, and these pieces of 
information can assist in establishing the true time of the OBS.  I'm so 
grateful that I discovered long ago that UTC is simpler, not more 
complicated, and I present plain UTC in my reports with much confidence 
I'd do worse if I tried to convert back. 
 
Also, there is a preference for PPAS for an even number of periods.  I 
vary from that only when I have a good reason.  For some reason, I've been 
finding reasons a lot lately.  But note my sensitivity to the possibility 
of sub-periods which overrides this tendency when it appears. 
 
And also a preference for ending times for PPAS.  I started with beginning 
times, and persist in fear of causing total confusion.