10 Geosyncs brightening at shadow entry

Mike McCants (mikem@fc.net)
Thu, 7 Oct 1999 12:17:21 -0500 (CDT)

Last night Ed Cannon and I saw about 10 geosynchronous objects
going into the Earth's shadow over a period of about 2 1/2 hours.
Observations were from BCRC: 30.314N  97.866W

The brightest was 23915 (96 35A) Intelsat 709.  It was about magnitude 4.
Ed could see it with his unaided eye, but it was difficult for me.

Over the span from about 9PM to 11:30PM CDT Oct. 6 (0200 to 0430 Oct 7 UT),
the shadow entry location gradually changed from about RA 0h 44m dec -5.0
(1950 coordinates) to 0h 37m -5.0.  During this time this place in the
sky rose from about alt 21 azi 109 to alt 44 azi 135.  Since our observing
site is west of Austin, the sky brightness is fairly bad to the east.

Binoculars, a 12x80 finder, and my 8 inch Dob were used.

The object 23536 (95 16A) Brasilsat B2 was about 6th magnitude, but
"dipped" in brightness alternately to 7th or 9th every 2.07 seconds.
The object 23199 (94 49A) Brasilsat B1 22 minutes behind it showed
similar behavior.  It was magnitude 6 and dipped to magnitude 9
every 2.02 seconds.

Ed Cannon saw an unknown flashing geosync about 10:16PM (3:16UT) about
RA 1h 5m, dec -10.3 degrees (1950).  Apparently it went into the shadow
soon after this.  He said it flashed to about magnitude 6 about every
45 or 50 seconds.

I have rewritten HighFly in a special form that generates only eclipse
predictions.  It can be found as http://www.fc.net/~mikem/ftp/highecl.zip.
It generates predictions only when an object is between 2.5 degrees
outside to 0.5 degrees inside of the Earth's shadow.

The output below shows 21 objects that went into the shadow over a 3 hour
period.  Now all I have to do is figure out exactly which ones we saw.

Mike McCants
 
(These predictions are 1950 coordinates.)
 
*** 1999 Oct  6  Wed evening *** Times are CDT 

Hrs Min  Alt Azi  Mag    Hgt    R  A    Dec  Range
 
19217 PAS 1 (Panamsa 88-051C  329**  .2 ELDY  2 M2   -3
  9  10   23 111  8.6  22243   0 34.8  -5.0  24375   2.1
  9  15   23 111  8.6  22243   0 39.8  -5.0  24375   1.0
  9  20   23 111  8.6  22243   0 44.8  -5.0  24375    .0
 
20705 TDF 2          90-063A  3.5** 5.1 ELDY  2 M2   -1
 10  45   41 131 13.2  22653   0 31.9  -5.9  23844   1.5
 10  50   41 131 13.2  22652   0 36.7  -5.9  23842    .5
 10  55   41 131 13.2  22650   0 41.6  -5.9  23840   -.3
 
20872 SBS 6          90 91A    26 M 3.5 ELDY  4 M2   -2
 11   5   46 139 11.5  22245   0 21.2  -5.2  23197   2.5
 11  10   46 139 11.5  22245   0 26.2  -5.2  23197   1.4
 11  15   46 139 11.5  22245   0 31.2  -5.2  23197    .4
 
22314 TDRS F6        93-003B 1000**-1.0 ELDY  4 M2   -3
  9  20   25 113  7.4  22246   0 36.0  -5.7  24299   2.1
  9  25   25 113  7.4  22246   0 41.0  -5.7  24299   1.1
  9  30   25 113  7.4  22246   0 46.0  -5.7  24299    .1
 
23051 GOES 8         94 22A    13 M 3.5 ELDY  2 M2   -2
 11  10   47 140 11.5  22252   0 23.0  -5.4  23194   2.1
 11  15   47 140 11.5  22252   0 28.0  -5.4  23195   1.1
 11  20   47 140 11.5  22252   0 33.1  -5.4  23195    .1
 
23199 Brasilsat B1   94-049A   11** 3.9 ELDY  5 M2   -2
 10  50   44 134 11.9  22245   0 24.4  -5.2  23316   2.2
 10  55   44 134 11.9  22245   0 29.4  -5.2  23316   1.2
 11   0   44 134 11.9  22245   0 34.4  -5.2  23316    .1
 
23413 ORION 1        94-079A   82** 1.7 ELDY  4 M2   -2
  8  40   17 106 10.4  22247   0 36.0  -4.9  24771   2.2
  8  45   17 106 10.4  22247   0 41.0  -4.9  24771   1.1
  8  50   17 106 10.4  22247   0 46.0  -4.9  24771    .1
 
23426 LUCH           94-082A  8.0** 4.2 ELDY  2 M2   -3
 10   5   33 122 12.4  22252   0 36.1  -6.3  23843   1.6
 10  10   33 122 12.4  22252   0 41.1  -6.3  23843    .7
 10  15   33 122 12.4  22252   0 46.1  -6.3  23843   -.2
 
23536 BRAZILSAT B2   95-016A   21** 3.2 ELDY  5 M2   -3
 10  30   40 128 11.3  22244   0 27.2  -5.1  23487   2.2
 10  35   40 128 11.3  22244   0 32.2  -5.1  23487   1.1
 10  40   40 128 11.3  22244   0 37.2  -5.1  23487    .1
 
23571 Intlst 7F6     95 23A    23 M 3.5 ELDY  7 M2   -3
  9  45   30 117 11.7  22247   0 34.7  -5.0  23982   1.6
  9  50   30 117 11.7  22247   0 39.7  -5.0  23982    .5
  9  55   30 117 11.7  22247   0 44.7  -5.0  23982   -.5
 
23764 PAS 3R         96-002A   32** 2.7 ELDY  3 M2   -2
  9   5   22 110 11.2  22248   0 37.7  -4.9  24476   1.6
  9  10   22 110 11.2  22248   0 42.7  -4.9  24476    .5
  9  15   22 110 11.2  22248   0 47.8  -4.9  24476   -.5
 
23915 INTELSAT 709   96-035A  116** 1.3 ELDY  8 M2   -2
  9  30   28 114  9.6  22246   0 33.1  -5.0  24126   2.1
  9  35   28 114  9.6  22246   0 38.2  -5.0  24126   1.0
  9  40   28 114  9.6  22246   0 43.2  -5.0  24126    .0
 
24714 NAHUEL 1A      97-002B   18** 3.4 ELDY  2 M2   -2
 11   0   45 136 11.4  22255   0 26.5  -5.1  23271   1.6
 11   5   45 136 11.4  22255   0 31.5  -5.1  23271    .5
 11  10   45 136 11.4  22255   0 36.5  -5.1  23271   -.5
 
24819 INMARSAT 3-F4  97-027A   25** 3.0 ELDY  4 M2   -3
  9  45   31 118 11.2  22251   0 30.4  -5.0  23941   2.4
  9  50   31 118 11.2  22251   0 35.4  -5.0  23941   1.3
  9  55   31 118 11.2  22251   0 40.4  -5.0  23941    .3
 
24891 PAS 6          97-040A   16** 3.5 ELDY  4 M2   -2
  9   5   22 110 12.0  22244   0 37.0  -5.0  24465   1.8
  9  10   22 110 12.0  22244   0 42.0  -5.0  24465    .7
  9  15   22 110 12.0  22244   0 47.0  -5.0  24465   -.3
 
24916 PAS 5          97-046A  4.0** 5.0 ELDY  5 M2   -3
 10   5   34 121 13.2  22284   0 33.6  -5.0  23805   1.4
 10  10   34 121 13.2  22284   0 38.6  -5.0  23805    .4
 
25004 ECHOSTAR 3     97-059A 1000**-1.0 ELDY  5 M2   -3
 10  15   37 124  7.1  22246   0 28.0  -5.1  23625   2.3
 10  20   37 124  7.1  22246   0 33.0  -5.1  23624   1.3
 10  25   37 124  7.1  22246   0 38.0  -5.1  23624    .2
 
25239 Intelsat 806   98 14A    33** 2.7 ELDY  7 M2   -2
  8  55   20 108 11.3  22250   0 38.7  -4.9  24615   1.5
  9   0   20 108 11.3  22250   0 43.7  -4.9  24615    .5
 
25371 INTELSAT 805   98-037A   12** 3.8 ELDY  4 M2   -3
  9  55   32 119 12.0  22249   0 34.2  -5.1  23875   1.5
 10   0   32 119 12.0  22249   0 39.2  -5.1  23876    .5
 
25516 GE 5           98-063B   38** 2.6 ELDY  6 M2   -2
 11  25   49 146 10.5  22247   0 19.2  -5.2  23079   2.3
 11  30   49 146 10.5  22247   0 24.3  -5.2  23079   1.3
 11  35   49 146 10.5  22247   0 29.3  -5.2  23079    .2
 
25585 PAS 6B         98-075A   12** 3.8 ELDY 10 M2   -2
  9   5   22 110 12.3  22243   0 36.4  -5.0  24456   1.8
  9  10   22 110 12.3  22243   0 41.5  -5.0  24456    .8
  9  15   22 110 12.3  22243   0 46.5  -5.0  24456   -.2