RE: Ident required

Ted Molczan (molczan@home.com)
Mon, 8 Feb 1999 21:13:49 -0500

G. Watmore requested:

> Please forgive the lack of technical data regarding the following
>
> On the 13.4.68 at approximately 3.05am I observed an object travelling
> west to east  approx 60 deg elevation.
>
> Would be interested in any information pertaining to this object.
> I apoloize once  again for the lack of data.
>
> My location;50.9000 N  1.4999W

Thanks to Russell Eberst's intuition and Vladimir Agapov's archival
elements, I believe I can confirm that you probably saw Echo 1.

Using the elset nearest in epoch to your observation:

1 00049U 60009  A 68106.74669761  .00407091 +00000-0 +00000-0 0 06274
2 00049 047.2791 119.1326 0155560 273.3109 084.9897 14.18644318354776

I obtain the following ephemeris:

13/ 4/68  00:00 - 06:00 UTC  J2000.0  EL >  1  G Watmore
Echo 1         60009A      49   Bull = 627     G Watmore
SGP4  Age =   -2.7 d  Unc =   18 s ( 10%)

  TIME      %I   Mv     AZ  EL    R.A.    DEC   FE   VANG  RANGE   ALT
--------    --  ----   ---  --   -----  ------  --   ----  -----  -----
02:05:12 LU 92  -1.9   226  55   13:41   23:02   4   0.35   1128    958
02:05:33    91  -1.9   214  59   14:13   23:25   4   0.38   1091    958
02:05:35 LP 91  -1.9   213  59   14:16   23:26   4   0.38   1088    958
02:05:55    89  -1.9   198  61   14:48   23:17   3   0.39   1069    957
02:06:14    87  -1.9   183  62   15:19   22:42   3   0.39   1065    957
02:06:33    84  -1.9   169  60   15:50   21:41   2   0.39   1076    956
02:06:52    81  -1.8   156  58   16:19   20:19   2   0.37   1100    955
02:07:12    77  -1.7   146  54   16:47   18:37   2   0.35   1140    955
02:07:34    73  -1.5   138  49   17:15   16:33   2   0.32   1199    954
02:07:58    69  -1.3   131  44   17:42   14:13   1   0.28   1278    953
02:08:25    65  -1.0   125  39   18:08   11:39   1   0.25   1382    951
02:08:56    60  -0.8   121  33   18:33   08:53   1   0.21   1518    950
02:09:32    56  -0.4   117  28   18:57   05:59   1   0.17   1693    948
02:10:15    51  -0.1   114  22   19:20   02:56   1   0.14   1917    945

The above times are UTC, which would agree with your time if it was given as
local Daylight Saving Time.

The object left the penumbra of the Earth's shadow at 02:05:35 UTC, at
azimuth 213 deg and elevation  59 deg, and culminated soon after at 62 deg
elevation, again in close agreement to your observation. The visual
magnitude would have been about -2.

Ted Molczan