Calculations 95-58 B DRA-obs
Leo Barhorst (leobarhorst@pi.net)
Sun, 01 Dec 1996 20:31:50 +0100
DRA observation of 95- 58 B on November 14 and 15, 1996
1. Introduction
Pierre Neirinck send me a letter November 17, 1996 in which he describes hi=
s examination =
of the two DRA obs I've made of 95- 58 B on Novem=1Fber 14 and 15, 1996 and=
his own of Nov =
14, 1995 and Nov 8, 1996. Due to busy work I was not able to put this to Se=
eSat-L any =
sooner.
2. Pierre's letter
"e&
Malo les Bains, 17/11/96
Dear Leo,
95-58 B: Your astonishing string of 72 flash intervals, wit=1Fhout fail, co=
erces me into =
linking them 2 by 2, in order to eliminate synodic, dissymmetric and Barhor=
stic effects.
The rocket took 6 flashes to accustom you to her flash rythm, them you were=
at the peak =
of your form. Let you admire, for ex, flashnr 23/24 to 37/38: 3.795, 3.715,=
3.81, 3.825, =
3.705, 3.725, 3.785, 3.84 sec.
Combining intervals 6 by 6, I find for fl 12/18 to 60/66: 22.69, 22.60, 22.=
915, 22.415, =
23.225.
Having assesed your accuracy, I was authorized, statistically, to find the =
differences =
between the 2 sides of the rocket. Adding all uneven flash intervals on one=
hand and all =
even ones on the other (fortunately I have two hands) and discar=1Fding the=
6 first =
wavering flashes and a few extreme intervals, I get out of 24 sets quite si=
gnificant =
results:
NOV 14 uneven: 3.833 sec
even: 3.683 sec
The next night, without the 2 first flashes, I have from all the others:
NOV 15 uneven: 3.873 sec
even: 3.718 sec
There is also evidence of synodic effect, northbound:
NOV 14 fl 0 to 36 3.750
36 to 72 3.809 ->+0.059 i.e +0.0016/fl
NOV 15 fl 0 to 20 3.758
20 to 40 3.808 ->+0.050 i.e. +0.0025/fl
On Nov 08 04:54, southbound, I took every 4th flash. This gave: 3.63, 3.548=
, 3.655, =
3.503, 3.66, 3.562, 3.55 sec. But this does not lead to the precious data s=
uch as =
derived from your feat.
Mean photometric periods from us were:
PN 1995 Nov 14.232 0.47 sec +/-0.03
] -> x 7.6
PN 1996 Nov 08.204 3.582 +/-0.008
] -> x 1.055
LB 1996 Nov 14.767 3.779 +/-0.007
LB 1996 Nov 15.758 3.783 +/-0.007
If you wish you may put all or part of these adventures on the waves.
Pierre
&unquote&
3. DRA obs
I've used a spreadsheet program to calculate the time differences between t=
he flashes =
and of the selected even and uneven flashes in the same manner as Pierre ha=
s done =
according to the draft calculations he was so kind to send me
Date 1996 Nov 14.767 Average Selected flashes
Flash Cum Diff 2 by 2 uneven even
0 0,00 0,00
1 2,68 2,68
2 7,17 4,49 3,585
3 10,83 3,66
4 14,90 4,07 3,865
5 18,24 3,34
6 21,94 3,70 3,520
7 25,61 3,67 3,67
8 29,31 3,70 3,685 3,70
9 33,12 3,81 3,81
10 36,91 3,79 3,800 3,79
11 40,55 3,64 3,64
12 44,40 3,85 3,745 3,85
13 48,11 3,71 3,71
14 52,15 4,04 3,875 4,04
15 56,33 4,18 4,18
16 59,94 3,61 3,895 3,61
17 63,36 3,42 3,42
18 67,21 3,85 3,635 3,85
19 70,56 3,35
20 74,83 4,27 3,810
21 78,77 3,94 3,94
22 82,21 3,44 3,690 3,44
23 86,00 3,79 3,79
24 89,80 3,80 3,795 3,80
25 93,62 3,82 3,82
26 97,23 3,61 3,715 3,61
27 101,03 3,80 3,80
28 104,85 3,82 3,810 3,82
29 108,66 3,81 3,81
30 112,50 3,84 3,825 3,84
31 116,25 3,75 3,75
32 119,91 3,66 3,705 3,66
33 123,70 3,79 3,79
34 127,43 3,73 3,760 3,73
35 131,34 3,91 3,91
36 135,00 3,66 3,785 3,66
37 138,94 3,94 3,94
38 142,68 3,74 3,840 3,74
39 146,17 3,49
40 150,54 4,37 3,930
41 154,43 3,89 3,89
42 158,04 3,61 3,750 3,61
43 162,02 3,98 3,98
44 165,39 3,37 3,675 3,77
45 169,71 4,32
46 173,57 3,86 4,090
47 176,91 3,34
48 180,83 3,92 3,630
49 184,68 3,85 3,85
50 187,98 3,30 3,575 3,30
51 192,00 4,02 4,02
52 195,30 3,30 3,660 3,30
53 199,14 3,84
54 203,37 4,23 4,035
55 207,32 3,95 3,95
56 210,65 3,33 3,640 3,33
57 215,02 4,37
58 218,25 3,23 3,800
59 222,42 4,17
60 225,66 3,24 3,705
61 229,50 3,84 3,84
62 233,25 3,75 3,795 3,75
63 237,14 3,89 3,89
64 241,25 4,11 4,000 4,11
65 245,00 3,75 3,75
66 248,53 3,53 3,640 3,53
67 252,50 3,97 3,97
68 255,85 3,35 3,660 3,55
69 259,47 3,62
70 263,79 4,32 3,970
71 267,84 4,05
72 272,11 4,27 4,160
=
Time total 272,11
=
MT even 3,771 fl 2 - 72
MT uneven 3,788 fl 1 - 71
=
MT uneven selected flashes 3,838
MT even selected flashes 3,685
Date 1996 Nov 15.758 Selected flashes
Flash Cum Diff uneven even
0 0,00 0,00
1 2,78 2,78
2 6,97 4,19
3 10,97 4,00 4,00
4 14,55 3,58 3,58
5 18,40 3,85 3,85
6 22,26 3,86 3,86
7 25,78 3,52 3,52
8 29,53 3,75 3,75
9 33,37 3,84 3,84
10 37,22 3,85 3,85
11 41,37 4,15 4,15
12 44,99 3,62 3,62
13 49,05 4,06 4,06
14 53,01 3,96 3,96
15 56,59 3,58 3,58
16 60,12 3,53 3,53
17 64,17 4,05 4,05
18 67,84 3,67 3,67
19 71,69 3,85 3,85
20 75,16 3,47 3,47
21 79,05 3,89 3,89
22 82,90 3,85 3,85
23 86,94 4,04 4,04
24 90,73 3,79 3,79
25 94,22 3,49 3,49
26 97,74 3,52 3,52
27 102,08 4,34 4,34
28 105,84 3,76 3,76
29 109,55 3,71 3,71
30 113,15 3,60 3,6
31 117,33 4,18 4,18
32 120,97 3,64 3,64
33 124,65 3,68 3,68
34 128,69 4,04 4,04
35 132,51 3,82 3,82
36 136,09 3,58 3,58
37 139,75 3,66 3,66
38 143,61 3,86 3,86
39 147,47 3,86
40 151,33 3,86
=
Time total 151,33
Mean flash period 3,783
=
Mean period selec. uneven fl 3,889
Mean period selec. even fl 3,718
4. Some remarks
In the calculations of the flashperiod for the two sides of the rocket on N=
ov 15 also =
the last 2 flashes were not used by Pierre, according to his draft calculat=
ions.
With these two also included the times become:
NOV 14 uneven: 3.887 sec
even: 3.725 sec
The spreadsheet calculated times of the selected flashes differ slightly fr=
om the hand =
calculated ones by Pierre.
For the synodic effect I think the first few flashes from both observations=
should be =
omitted for reasons stated in Pierre's letter.
This gives:
NOV 14 fl 7 to 40 128.60 / 34 =3D 3.782 sec
fl 41 to 72 121.57 / 32.=3D 3.799 sec
NOV 15 fl 3 to 22 75.93./ 20 =3D 3.797 sec
fl 23 to 40 68.43 / 18 =3D 3.802 sec
Both give a very little difference over the first and second half of the ob=
servations =
and also for the two consecutive days.
For the same reason they should be omitted in the calculation of the mean p=
hotometric =
period:
NOV 14 fl 7 to 72 250.17 / 66 =3D 3.790 sec
NOV 15 fl 3 to 40 144.36 / 38 =3D 3.799 sec
5. Conclusion
It is obvious that a large number of flash timings is very usefull. But one=
has to be =
carefull as to what measurements could be accurate enough to be inclueded i=
n the =
calculations.
I sincerly thanks Pierre for his effort and time to do the calculations. Ju=
st as I was =
preparing this message I got a fax from Pierre. Due to the rainy weather h=
e only saw =
one satellite: 95- 58 B on Nov 23 with P=3D 4.145 =F10.02 sec.
Im my archive I found some more DRA-obs of 95- 58 B. So there will be a fol=
low-up on =
this message.
Greetings
Leo Barhorst Alkmaar The Netherlands
52.6333 North 4.7833 East 3 m ASL
Member of Seesat-L
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Every day I wonder about the things I see in the (night)sky