RE: Observation 96072A

Ted Molczan (molczan@fox.nstn.ca)
Tue, 21 Jan 1997 03:42:13 -0500

Greg Roberts wrote:

>Observation on 20th Jan 1997 from my usual site of 96072A as follows:
>#24680 96072A 19h52m59.3s UT RA 11h47.7m,Dec -40d19' (J2000)
>There may be a slight timing error-I had no time signals for about 10 minutes
>either side of the observation so had to stop the one stopwatch against my
>other stopwatch which I use as a "clock". This earlier had as error of about
>1.5 seconds and I have corrected the time above for this.

Your position appears to be very accurate, as usual, but the time is 
about 2.9 s early, relative my 97018.858 elset, as judged from this 
ephemeris:
 
  TIME      %I   Mv     AZ  EL    R.A.    DEC   FE   VANG  RANGE   ALT
--------    --  ----   ---  --   -----  ------  --   ----  -----  -----
19:52:57    59   6.4   129  14   11:51  -40:50   4   0.17   2004    764
19:52:58    59   6.4   129  14   11:51  -40:44   4   0.17   1999    764
19:52:59    59   6.4   129  14   11:50  -40:38   4   0.17   1994    763
19:53:00    60   6.4   129  14   11:49  -40:32   4   0.17   1990    763
19:53:01    60   6.4   129  14   11:48  -40:26   4   0.17   1985    762
19:53:02    60   6.4   129  14   11:48  -40:20   4   0.18   1981    762
19:53:03    60   6.4   128  14   11:47  -40:14   4   0.18   1976    762
19:53:04    60   6.4   128  14   11:46  -40:08   4   0.18   1971    761


I would have to multiply the decay rate over the past 2 days by a factor 
of about 3, to account for this, but that is virtually impossible, since 
the sun has remained quiet during that period. 

The difference also is well outside the uncertainty in the mean motion.

One possible explanation - could you have applied the 1.5 s correction 
in the wrong direction, i.e subtracted, instead of added?

>#24681 96072B -- looked for it but not seen.Shadow entry was predicted for 8
>degrees and I cannot access this elevation from my site using my 5 inch
>tracking telescope so I tried 7x50 binoculars. 

The situation may have been even worse. My ephemeris for your site indicates
shadow entry (mid-point of penumbra) at 6 deg. It would have reached the
umbra at about 7 deg.

  TIME      %I   Mv     AZ  EL    R.A.    DEC   FE   VANG  RANGE   ALT
--------    --  ----   ---  --   -----  ------  --   ----  -----  -----
20:31:40    35   4.6   150   6   14:23  -51:29   4   0.13   1732    415
20:31:41    35   4.6   150   6   14:22  -51:28   4   0.13   1725    415
20:31:42    35   4.6   150   6   14:21  -51:28   4   0.13   1719    414
20:31:43    35   4.6   150   6   14:21  -51:28   4   0.13   1712    414
20:31:44    36   4.6   150   6   14:20  -51:28   4   0.13   1705    414
20:31:45    36   4.5   150   6   14:19  -51:27   4   0.13   1698    414
20:31:46    36   4.5   150   6   14:18  -51:27   4   0.13   1692    413
20:31:47 ES 36   4.5   150   6   14:18  -51:26   4   0.13   1686    413

>Since I could not see any
>stars fainter than about 3rd magnitude in the binoculars, due mainly to city
>orange sky glow, Im not suprised I did not see 96072B. 

I have the same problem here in Toronto - rarely can see much below 10 deg
elevation.

Clear skies and horizons!
Ted