Detailed Superbird A obs, 16 Feb 97 UT

Ron Lee (ronlee@pcisys.net)
Sun, 16 Feb 1997 12:58:52 -0700 (MST)

My previous posting was one day in the future.  Obs was 
made on 15 Feb local (MST or UT-7)   All times provided
here will be UT on 16 Feb 97.

Initial obs was about 02:15.7 UT.  Was checking star
magnitudes when I  noticed the first flash.  Could have been
flashing earlier but I was not observing.

Period between 02:16 and about 02:31 UT are not documented
due to equipment and human factor problems.  The initial
recorded times are from a tape recorder, then all subsequent
times are from my stopwatch.

WWV was not coming in so I had to time hack the tape recorder
from my watch, which was set to WWV earlier that day.  Errors
of 0.5 second (or more) absolute are likely in the initial 
timings.

Timings are rounded to 0.1 second which may cause small errors
when adding the time between flashes, so I am including the
UT time as well.

The magnitude around 2:31 UT was reported as 4-5.  It may well
have been around 1st magnitude.  Will attempt a naked eye obs
tonight to check the maximum.

My thoughts:  My period (using obs #69 and 20 which should be
50 periods) is 23.38 seconds.  Considering my possible timing
errors, that is the same as Rainer's from last week.  Differences
fron Rainer's obs was that I observed the secondary flashes.
It is also probable that my maximum brightness was 2-4 magnitudes
greater than Rainer observed.

By 2:39 UT, the flashes disappeared. When recovered a few minutes
later, the secondary flashes were missing.

Obs   Delta time        UT of Obs       Comment
1       ---             2:31:18.1       Bright
2       11.6            2:31:29.7       Very Bright
3       11.6            2:31:41.3       Bright  
4       11.8            2:31:53.1       Bright
5       11.7            2:32:04.3       Bright

Jumped to a different tape time hack for next obs

6       ---             2:32:16.0       Bright
7       11.7            2:32:27.6       Bright
8       11.6            2:32:39.2       Bright, but fainter
9       11.6            2:32:50.8       Bright
10      11.9            2:33:02.7       A little fainter
11      11.5            2:33:14.2       Same as previous
12      11.7            2:33:25.8
13      11.8            2:33:37.6       little fainter
14      11.6            2:33:49.2       Fainter overall
15      11.9            2:34:01.2
16      11.5            2:34:12.7       Faint
17      11.8            2:34:24.4       Same as previous

Now pick up timings from stopwatch, using 2:34 UT from my
watch as a zero point.

18      ---             2:34:36.8       (discontinuity here)
19      11.7            2:34:48.5
20      11.7            2:35:00.2
21      11.7            2:35:11.9
21      11.7            2:35:23.5
22      11.7            2:35:35.3
23      12.0            2:35:47.3
24      11.4            2:35:58.7       (#23 was a late time)
25      11.7            2:36:10.4
26      11.7            2:36:22.0
27      11.5            2:36:33.6
28      11.9            2:36:45.5       Faint
29      11.5            2:36:56.9       Faint
30      11.9            2:37:08.9       Brighter than previous
31      Missed a flash
32      ---             2:37:32.4
33      Missed
34      Missed
35      ---             2:38:07.5
36      12.1            2:38:19.6       (Late time) Faint
37      11.2            2:38:30.8       (see previous error) Faint
38      11.7            2:38:42.5       Faint
39      11.7            2:38:54.3       Faint
40      11.9            2:39:06.2       Faint

Invisible for a few minutes

41      ---             2:44:21.3
42      23.4            2:44:44.6       (no more secondary flashes)
43      23.4            2:45:08.0       Same brightness, fainter than 2:34 UT
44      23.4            2:45:31.3
45      23.3            2:45:54.6       Mag 9.5
46      23.6            2:46:18.1
47      23.4            2:46:41.5
48      23.4            2:47:04.9       Getting fainter
49      23.4            2:47:28.3
50      23.4            2:47:51.7
51      23.7            2:48:15.3       Late timing
52      23.2            2:48:38.5
53      23.3            2:49:01.8
54      23.3            2:49:25.2
55      23.8            2:49:48.9
56      23.2            2:50:12.1
57      23.6            2:50:35.7
58      23.1            2:50:58.8
59      23.3            2:51:22.2
60      23.4            2:51:45.6
61      23.3            2:52:08.9
62      23.3            2:52:32.3
63      23.5            2:52:55.7
64      23.3            2:53:19.0
65      23.4            2:53:42.4
66      23.4            2:54:05.8
67      23.4            2:54:29.2
68      23.5            2:54:52.7

Invisible for a while

69      ---             2:58:46.6
70      missed one
71      46.9            2:59:33.5
72      Missed one
73      46.7            3:00:20.2
74      Missed a few
75      ----            3:01:42.3

Clouds came in at this point: maybe 
sooner causing misses.