StarWatch for the greater Lehigh Valley
---------------

MAY  1998

MAY 10 | MAY 17 | MAY 24 | MAY 31 | MAY STAR MAP | INDEX
088   MAY 3, 1998:   More about Iridium
Iridium flares are highlighted again this week as the moon continues to brighten in the evening sky. Motorola’s Satellite Communications Group in Chandler, Arizona has been assembling the small communications satellite for Iridium LLC with a frequency of about one satellite every five days. The mechanism providing the flares/glints appears to be three highly reflective aluminum flat plates, each separated by 120 degrees. These compose the Main Mission Antennae of the satellite. Each plate is only 18 square feet in area, but the momentary flashes which they are capable of producing can be over two dozen times brighter than the planet Venus. Because the orientation of the satellite must be precisely maintained, it is possible to predict with a high degree of accuracy the brightness of these flashes for specific locations on the Earth. Knowing your latitude and longitude position will allow you to make precise predictions for your own backyard. Link up with the German Space Operations Centre (GSOC) Home Page which will allow precise predictions for your specific position. Access can be obtained from the ASD Planetarium’s Home Page address found below. Specific flare predictions for Allentown, Bethlehem, and Reading are given in the expanded StarWatch column found at the Planetarium’s web site.
Observer's Location: Allentown ( 40.60°N, 75.47°W)
Local Time: Eastern Daylight Time (GMT - 4:00)

DateTimeIntensity
(Mag.)		Elev.AzimuthMirror
Angle		Satellite
03 May 02:55:58 1 14° 125° (SE) 2.7° Iridium 64
03 May 03:06:29 -3 19° 128° (SE) 0.5° Iridium 65
03 May 03:14:11 -1 24° 129° (SE) 1.3° Iridium 66
03 May 05:30:54 2 20° 29° (NE) 2.8° Iridium 22
03 May 05:39:25 1 26° 27° (NE) 1.8° Iridium 23
03 May 05:40:48 1 27° 27° (NE) 1.9° Iridium 48
03 May 21:27:23 -1 55° 81° (E ) 1.7° Iridium 36
03 May 22:33:32 2 13° 47° (NE) 3.6° Iridium 53
03 May 22:43:08 -0 16° 49° (NE) 1.2° Iridium 56
03 May 22:52:37 0 20° 51° (NE) 1.7° Iridium 50
04 May 02:59:31 0 18° 128° (SE) 1.7° Iridium 68
04 May 04:26:31 3 11° 85° (E ) 3.5° Iridium 49
04 May 05:24:49 2 19° 28° (NE) 2.2° Iridium 25
04 May 05:33:28 1 25° 27° (NE) 1.9° Iridium 45
04 May 21:21:19 -7 54° 82° (E ) 0.1° Iridium 7
04 May 22:37:09 1 17° 50° (NE) 2.5° Iridium 10
04 May 22:46:37 -5 20° 52° (NE) 0.3° Iridium 9
05 May 03:08:06 -1 26° 133° (SE) 1.4° Iridium 63
05 May 03:10:01 0 27° 133° (SE) 2.3° Iridium 62
05 May 04:20:31 2 11° 86° (E ) 2.6° Iridium 22
05 May 04:25:44 2 12° 87° (E ) 3.0° Iridium 48
05 May 04:29:26 3 14° 88° (E ) 3.6° Iridium 23
05 May 05:10:19 3 14° 28° (NE) 3.8° Iridium 24
05 May 05:18:53 0 18° 28° (NE) 1.2° Iridium 47
05 May 21:15:16 -1 53° 83° (E ) 1.9° Iridium 35
05 May 22:31:06 2 16° 51° (NE) 3.9° Iridium 12
05 May 22:40:35 -1 20° 53° (NE) 1.0° Iridium 13
05 May 22:50:00 1 25° 54° (NE) 2.5° Iridium 14
06 May 03:01:51 2 18° 296° (NW) 3.9° Iridium 39
06 May 03:05:07 -0 27° 135° (SE) 1.7° Iridium 65
06 May 04:14:10 1 11° 88° (E ) 1.6° Iridium 25
06 May 04:23:17 2 13° 89° (E ) 2.7° Iridium 45
06 May 05:04:20 3 13° 27° (NE) 2.8° Iridium 49
06 May 05:12:57 -2 17° 27° (NE) 0.5° Iridium 26
06 May 21:09:13 0 53° 84° (E ) 3.6° Iridium 34
06 May 22:34:31 1 21° 54° (NE) 2.4° Iridium 53
06 May 22:44:01 -1 25° 55° (NE) 1.1° Iridium 56
06 May 22:52:13 0 28° 57° (NE) 2.6° Iridium 52
07 May 02:46:43 1 22° 296° (NW) 3.2° Iridium 17
07 May 02:55:45 1 18° 296° (NW) 2.7° Iridium 15
07 May 02:56:26 1 18° 295° (NW) 2.5° Iridium 18
07 May 02:57:30 1 28° 130° (SE) 4.0° Iridium 68
07 May 04:07:59 -1 10° 89° (E ) 0.7° Iridium 47
07 May 04:26:13 2 16° 92° (E ) 3.1° Iridium 49
07 May 04:58:25 2 12° 26° (NE) 1.9° Iridium 48
07 May 04:58:34 1 12° 26° (NE) 1.6° Iridium 22
07 May 05:06:57 -0 17° 26° (NE) 1.0° Iridium 23
07 May 21:12:20 0 63° 84° (E ) 3.8° Iridium 6
07 May 22:28:33 2 21° 55° (NE) 3.7° Iridium 54
07 May 22:37:58 -5 25° 56° (NE) 0.3° Iridium 10
07 May 22:47:21 1 30° 56° (NE) 4.0° Iridium 9
08 May 02:40:39 1 22° 297° (NW) 2.9° Iridium 38
08 May 02:49:46 -2 18° 295° (NW) 0.8° Iridium 41
08 May 02:58:40 2 15° 296° (NW) 3.0° Iridium 43
08 May 04:01:46 -4 10° 90° (E ) 0.2° Iridium 26
08 May 04:17:30 1 15° 93° (E ) 1.6° Iridium 48
08 May 04:20:15 1 16° 94° (E ) 2.2° Iridium 22
08 May 04:46:33 2 10° 26° (NE) 1.9° Iridium 46
08 May 04:52:28 -1 12° 26° (NE) 0.7° Iridium 25
08 May 05:01:04 1 16° 26° (NE) 1.6° Iridium 45
08 May 21:06:14 -0 63° 85° (E ) 2.9° Iridium 4
08 May 22:31:55 -0 25° 57° (NE) 1.8° Iridium 12
08 May 22:41:19 0 30° 57° (NE) 2.6° Iridium 13
08 May 22:47:12 1 32° 59° (NE) 3.5° Iridium 52
09 May 02:34:35 1 22° 297° (NW) 3.1° Iridium 20
09 May 02:52:30 1 15° 298° (NW) 2.1° Iridium 40
09 May 03:01:23 2 12° 300° (NW) 3.9° Iridium 39
09 May 03:55:30 0 10° 93° (E ) 1.0° Iridium 23
09 May 04:08:09 -3 14° 94° (E ) 0.4° Iridium 46
09 May 04:13:54 0 16° 95° (E ) 1.2° Iridium 25
09 May 04:23:06 2 19° 96° (E ) 3.1° Iridium 45
09 May 04:46:32 -2 11° 25° (NE) 0.5° Iridium 47
09 May 21:00:13 -2 63° 86° (E ) 1.4° Iridium 19
09 May 22:25:55 1 25° 58° (NE) 3.0° Iridium 16
09 May 22:35:13 -1 30° 58° (NE) 1.2° Iridium 53
10 May 02:28:31 2 22° 297° (NW) 3.8° Iridium 39
10 May 02:37:26 -1 18° 298° (NW) 1.0° Iridium 44
10 May 02:46:18 -0 15° 300° (NW) 1.2° Iridium 17
10 May 02:53:49 2 12° 301° (NW) 3.1° Iridium 42
10 May 02:54:54 2 11° 302° (NW) 3.2° Iridium 18
10 May 02:55:07 2 12° 302° (NW) 3.1° Iridium 15
10 May 03:49:37 2 10° 91° (E ) 2.6° Iridium 45
10 May 03:58:31 -0 12° 95° (E ) 0.9° Iridium 24
10 May 04:07:44 -4 15° 96° (E ) 0.3° Iridium 47
10 May 04:40:34 1 10° 25° (NE) 1.4° Iridium 26
10 May 04:50:17 3 15° 24° (NE) 3.7° Iridium 48
Observer's Location: Bethlehem ( 40.62°N, 75.38°W)
Local Time: Eastern Daylight Time (GMT - 4:00)

DateTimeIntensity
(Mag.)		Elev.AzimuthMirror
Angle		Satellite
03 May 02:55:58 1 14° 125° (SE) 2.6° Iridium 64
03 May 03:06:31 -4 19° 128° (SE) 0.5° Iridium 65
03 May 03:14:13 -1 24° 129° (SE) 1.4° Iridium 66
03 May 05:30:53 2 20° 29° (NE) 2.6° Iridium 22
03 May 05:39:24 1 26° 27° (NE) 2.0° Iridium 23
03 May 05:40:47 1 27° 27° (NE) 2.1° Iridium 48
03 May 21:27:22 -1 55° 81° (E ) 2.1° Iridium 36
03 May 22:33:33 2 13° 47° (NE) 3.5° Iridium 53
03 May 22:43:08 -1 17° 49° (NE) 1.1° Iridium 56
03 May 22:52:37 0 21° 51° (NE) 1.8° Iridium 50
04 May 02:59:31 0 18° 128° (SE) 1.6° Iridium 68
04 May 04:26:31 3 11° 85° (E ) 3.5° Iridium 49
04 May 05:24:48 1 19° 28° (NE) 2.0° Iridium 25
04 May 05:33:27 1 25° 27° (NE) 2.1° Iridium 45
04 May 21:21:19 -6 54° 82° (E ) 0.3° Iridium 7
04 May 22:37:10 1 17° 50° (NE) 2.4° Iridium 10
04 May 22:46:38 -4 21° 52° (NE) 0.4° Iridium 9
05 May 03:08:07 -1 26° 133° (SE) 1.5° Iridium 63
05 May 03:10:02 0 28° 133° (SE) 2.4° Iridium 62
05 May 04:20:31 2 11° 87° (E ) 2.6° Iridium 22
05 May 04:25:44 2 13° 87° (E ) 3.0° Iridium 48
05 May 04:29:27 3 14° 88° (E ) 3.7° Iridium 23
05 May 05:10:18 3 14° 28° (NE) 3.7° Iridium 24
05 May 05:18:52 -0 18° 28° (NE) 1.1° Iridium 47
05 May 21:15:16 -2 54° 83° (E ) 1.5° Iridium 35
05 May 22:31:06 2 17° 51° (NE) 3.8° Iridium 12
05 May 22:40:36 -1 21° 53° (NE) 0.9° Iridium 13
05 May 22:50:01 1 25° 54° (NE) 2.6° Iridium 14
06 May 05:04:19 2 13° 27° (NE) 2.7° Iridium 49
06 May 05:12:55 -3 17° 27° (NE) 0.4° Iridium 26
06 May 21:09:13 -0 53° 84° (E ) 3.2° Iridium 34
06 May 22:34:32 1 21° 54° (NE) 2.2° Iridium 53
06 May 22:44:01 -1 25° 55° (NE) 1.2° Iridium 56
06 May 22:52:13 0 28° 57° (NE) 2.8° Iridium 52
07 May 02:55:46 1 18° 296° (NW) 2.6° Iridium 15
07 May 02:56:27 1 18° 295° (NW) 2.4° Iridium 18
07 May 02:57:30 1 28° 130° (SE) 3.7° Iridium 68
07 May 04:07:59 -1 11° 89° (E ) 0.8° Iridium 47
07 May 04:26:14 2 16° 92° (E ) 3.2° Iridium 49
07 May 04:58:24 2 12° 26° (NE) 1.8° Iridium 48
07 May 04:58:33 1 13° 26° (NE) 1.5° Iridium 22
07 May 05:06:56 0 17° 26° (NE) 1.1° Iridium 23
07 May 22:28:33 2 21° 55° (NE) 3.6° Iridium 54
07 May 22:37:58 -6 25° 56° (NE) 0.2° Iridium 10
08 May 02:40:40 1 22° 296° (NW) 2.6° Iridium 38
08 May 02:49:38 -0 18° 297° (NW) 1.5° Iridium 41
08 May 02:58:40 2 15° 297° (NW) 3.1° Iridium 43
08 May 04:01:46 -4 10° 90° (E ) 0.1° Iridium 26
08 May 04:17:31 1 15° 93° (E ) 1.6° Iridium 48
08 May 04:20:16 1 16° 94° (E ) 2.3° Iridium 22
08 May 04:46:33 2 10° 26° (NE) 1.8° Iridium 46
08 May 04:52:27 -1 12° 26° (NE) 0.7° Iridium 25
08 May 05:01:03 1 16° 26° (NE) 1.7° Iridium 45
08 May 21:06:14 -0 64° 85° (E ) 3.4° Iridium 4
08 May 22:31:56 -0 25° 57° (NE) 1.6° Iridium 12
08 May 22:41:19 0 31° 57° (NE) 2.7° Iridium 13
08 May 22:47:12 1 32° 59° (NE) 3.7° Iridium 52
09 May 02:34:35 1 22° 297° (NW) 2.9° Iridium 20
09 May 02:52:29 1 15° 298° (NW) 2.2° Iridium 40
09 May 03:55:31 0 10° 93° (E ) 1.0° Iridium 23
09 May 04:08:10 -2 14° 94° (E ) 0.5° Iridium 46
09 May 04:13:54 0 16° 95° (E ) 1.3° Iridium 25
09 May 04:23:06 2 19° 96° (E ) 3.1° Iridium 45
09 May 04:37:31 3 9° 28° (NE) 3.1° Iridium 24
09 May 04:46:31 -1 11° 25° (NE) 0.5° Iridium 47
09 May 21:00:13 -1 64° 86° (E ) 1.8° Iridium 19
09 May 22:25:55 1 25° 58° (NE) 2.9° Iridium 16
09 May 22:35:13 -1 31° 58° (NE) 1.4° Iridium 53
10 May 02:28:31 2 22° 297° (NW) 3.6° Iridium 39
10 May 02:37:25 -1 18° 298° (NW) 0.9° Iridium 44
10 May 02:46:17 -0 15° 300° (NW) 1.3° Iridium 17
10 May 02:53:47 2 12° 302° (NW) 3.1° Iridium 42
10 May 02:54:52 2 11° 302° (NW) 3.3° Iridium 18
10 May 02:55:06 2 11° 302° (NW) 3.2° Iridium 15
10 May 03:49:32 2 10° 92° (E ) 2.1° Iridium 45
10 May 03:58:32 -0 12° 95° (E ) 0.9° Iridium 24
10 May 04:07:44 -3 15° 96° (E ) 0.4° Iridium 47
10 May 04:40:33 1 10° 25° (NE) 1.5° Iridium 26
10 May 04:50:16 3 15° 24° (NE) 3.8° Iridium 48
Observer's Location: Reading ( 40.34°N, 75.93°W)
Local Time: Eastern Daylight Time (GMT - 4:00)

DateTimeIntensity
(Mag.)		Elev.AzimuthMirror
Angle		Satellite
03 May 02:55:58 2 14° 123° (SE) 3.7° Iridium 64
03 May 03:06:17 -2 18° 128° (SE) 0.7° Iridium 65
03 May 03:14:00 -2 22° 129° (SE) 0.8° Iridium 66
03 May 05:30:56 3 19° 29° (NE) 3.5° Iridium 22
03 May 05:39:26 -2 25° 28° (NE) 0.7° Iridium 23
03 May 05:40:49 -1 25° 28° (NE) 0.8° Iridium 48
03 May 21:27:27 -7 52° 81° (E ) 0.1° Iridium 36
03 May 22:33:32 2 12° 46° (NE) 3.9° Iridium 53
03 May 22:43:08 0 16° 49° (NE) 1.6° Iridium 56
03 May 22:52:38 -1 20° 51° (NE) 1.2° Iridium 50
04 May 02:59:31 1 18° 126° (SE) 3.0° Iridium 68
04 May 04:26:26 3 11° 85° (E ) 3.3° Iridium 49
04 May 05:24:52 2 18° 28° (NE) 2.8° Iridium 25
04 May 05:33:30 -1 23° 27° (NE) 0.9° Iridium 45
04 May 21:21:24 -1 52° 82° (E ) 2.0° Iridium 7
04 May 22:37:10 1 16° 50° (NE) 2.9° Iridium 10
04 May 22:46:39 -5 19° 52° (NE) 0.2° Iridium 9
05 May 03:07:56 -2 24° 132° (SE) 0.8° Iridium 63
05 May 03:09:50 -0 26° 133° (SE) 1.6° Iridium 62
05 May 04:20:26 2 10° 86° (E ) 2.4° Iridium 22
05 May 04:25:38 2 12° 87° (E ) 2.7° Iridium 48
05 May 04:29:21 3 13° 88° (E ) 3.4° Iridium 23
05 May 05:18:56 1 17° 28° (NE) 1.8° Iridium 47
05 May 21:15:21 0 51° 83° (E ) 3.7° Iridium 35
05 May 22:40:37 -0 20° 53° (NE) 1.6° Iridium 13
05 May 22:50:02 0 24° 54° (NE) 1.8° Iridium 14
06 May 03:05:07 0 27° 132° (SE) 2.1° Iridium 65
06 May 04:14:05 1 10° 88° (E ) 1.5° Iridium 25
06 May 04:23:12 2 13° 89° (E ) 2.5° Iridium 45
06 May 04:32:19 3 16° 91° (E ) 3.8° Iridium 24
06 May 05:04:24 3 12° 27° (NE) 3.2° Iridium 49
06 May 05:13:00 0 16° 27° (NE) 1.1° Iridium 26
06 May 22:34:33 1 20° 54° (NE) 2.9° Iridium 53
06 May 22:44:02 -5 24° 55° (NE) 0.4° Iridium 56
06 May 22:52:16 -0 26° 57° (NE) 1.8° Iridium 52
07 May 02:55:45 2 18° 298° (NW) 3.4° Iridium 15
07 May 02:56:26 1 18° 297° (NW) 3.0° Iridium 18
07 May 03:04:31 2 15° 296° (NW) 3.7° Iridium 42
07 May 04:07:55 -1 10° 89° (E ) 0.6° Iridium 47
07 May 04:26:08 2 15° 92° (E ) 2.8° Iridium 49
07 May 04:58:29 2 11° 26° (NE) 2.3° Iridium 48
07 May 04:58:38 2 11° 26° (NE) 2.0° Iridium 22
07 May 05:07:01 -3 16° 26° (NE) 0.4° Iridium 23
07 May 21:12:24 -2 60° 84° (E ) 1.6° Iridium 6
07 May 22:38:00 -1 24° 56° (NE) 1.0° Iridium 10
07 May 22:47:24 1 29° 57° (NE) 3.1° Iridium 9
08 May 02:49:48 -1 19° 296° (NW) 1.1° Iridium 41
08 May 02:58:49 1 15° 296° (NW) 2.4° Iridium 43
08 May 04:02:08 3 10° 85° (E ) 3.5° Iridium 26
08 May 04:17:24 0 14° 93° (E ) 1.3° Iridium 48
08 May 04:20:09 1 15° 94° (E ) 1.9° Iridium 22
08 May 04:29:07 2 19° 95° (E ) 3.7° Iridium 23
08 May 04:46:24 3 10° 28° (NE) 3.2° Iridium 46
08 May 04:52:32 1 11° 26° (NE) 1.1° Iridium 25
08 May 05:01:08 0 15° 26° (NE) 1.0° Iridium 45
08 May 05:09:44 3 19° 25° (NE) 3.9° Iridium 24
08 May 21:06:19 -4 61° 85° (E ) 0.7° Iridium 4
08 May 22:31:58 1 24° 57° (NE) 2.4° Iridium 12
08 May 22:41:22 -0 29° 58° (NE) 1.7° Iridium 13
08 May 22:47:15 0 31° 59° (NE) 2.5° Iridium 52
09 May 02:52:39 0 15° 297° (NW) 1.6° Iridium 40
09 May 03:01:32 2 12° 299° (NW) 3.5° Iridium 39
09 May 03:55:49 3 10° 88° (E ) 3.2° Iridium 23
09 May 04:08:03 -4 13° 94° (E ) 0.2° Iridium 46
09 May 04:13:47 -0 15° 95° (E ) 1.0° Iridium 25
09 May 04:23:00 2 18° 96° (E ) 2.7° Iridium 45
09 May 04:46:36 -4 10° 25° (NE) 0.1° Iridium 47
09 May 21:00:18 -3 60° 86° (E ) 0.9° Iridium 19
09 May 22:25:57 1 24° 58° (NE) 3.7° Iridium 16
09 May 22:35:15 -5 29° 59° (NE) 0.3° Iridium 53
10 May 02:37:35 0 19° 297° (NW) 1.6° Iridium 44
10 May 02:46:27 -2 15° 299° (NW) 0.7° Iridium 17
10 May 02:53:58 1 12° 301° (NW) 2.6° Iridium 42
10 May 02:55:03 2 12° 301° (NW) 2.7° Iridium 18
10 May 02:55:17 1 12° 301° (NW) 2.6° Iridium 15
10 May 03:58:25 0 11° 95° (E ) 1.1° Iridium 24
10 May 04:07:37 -5 14° 96° (E ) 0.1° Iridium 47
10 May 04:25:58 2 22° 99° (E ) 3.8° Iridium 49
10 May 04:40:33 1 10° 25° (NE) 1.2° Iridium 26
10 May 04:50:20 3 14° 24° (NE) 3.1° Iridium 48
089   MAY 10, 1998:   Seeing MIR
Russia's MIR Space Station has been in orbit around the Earth for over 10 years. With its accomplishments, problems, and now its proposed decommissioning, interest to see MIR over US soil has increased. Actually, it's quite simple to spot MIR even from center city locations, because the space station looks like a brightly moving star. Remember that the horizon is divided into the four basic cardinal points: north, east, south, and west. Proceed from N clockwise a quarter turn to E, another quarter turn to S, etc. Altitude or elevation is measured from zero degrees, which is at the horizon, to 90 degrees, which is overhead. Synchronize your watch with a reliable time source and you are now set to view MIR. Times for MIR sightings are at maximum elevation above the horizon. Currently, MIR is only visible in the morning. On Monday at 04:48:53, look NW about 40 degrees above the horizon. On Tuesday, look N to see MIR catch the first glint of sun at 03:47:34 near the zenith. On Wednesday, you can spot MIR at an altitude of 26 degrees in the NW at 04:22:04. Thursday finds MIR in the N mid-sky at 03:21:11. Friday, look 20 degrees above the N horizon at 03:55:11. Saturday, look N at an elevation of 26 degrees at 02:54:34. More complete list of MIR sightings can be found at the Planetarium's web site given below.
Observer's Location: Allentown ( 40.60°N, 75.47°W)
Local Time: Eastern Daylight Time (GMT - 4:00)

DateStartsMax. ElevationEnds
TimeEl.Az.TimeEl.Az.TimeEl.Az.
06 May 05:05:55 10 S 05:08:18 21 SE 05:10:42 10 E
08 May 04:39:33 18 S 04:41:23 33 SE 04:44:13 10 E
09 May 03:40:38 14 SE 03:40:38 14 SE 03:41:58 10 E
09 May 05:12:44 10 SW 05:15:44 56 NW 05:18:50 10 NE
10 May 04:13:43 43 S 04:14:22 57 SE 04:17:29 10 NE
11 May 03:14:39 16 E 03:14:39 16 E 03:15:43 10 E
11 May 04:46:42 15 W 04:48:53 37 NW 04:51:51 10 NE
12 May 03:47:34 81 N 03:47:34 81 N 03:50:35 10 NE
13 May 02:48:23 15 E 02:48:23 15 E 02:49:03 10 E
13 May 04:20:26 17 W 04:22:04 26 NW 04:24:45 10 NE
14 May 03:21:11 41 N 03:21:11 41 N 03:23:33 10 NE
14 May 04:55:09 10 NW 04:56:55 14 N 04:58:42 10 N
15 May 02:21:53 12 NE 02:21:53 12 NE 02:22:09 10 NE
15 May 03:53:55 16 NW 03:55:11 20 N 03:57:35 10 NE
16 May 02:54:34 26 N 02:54:34 26 N 02:56:25 10 NE
16 May 04:28:41 10 NW 04:30:05 12 N 04:31:30 10 N
090    MAY 17, 1998:   Comet SOHO
On May 3 a bright comet was discovered by a satellite named the Solar and Heliospheric Observatory (SOHO). SOHO's goal is to help us better understand the interactions between the Sun-Earth environments. At the time of discovery the comet was only 8 degrees from the sun and inward bound. It reached its closest solar distance, perihelion (May 8), and its motion has now carried the comet to the sun's east. For us this means that Comet SOHO may become visible in our western sky shortly after sunset during this week. You will need an unobstructed western horizon, a very clear sky, and binoculars. Your best bet is to be at your observing site to witness the location of sundown. Use this as a horizon marker. Comet SOHO will be slightly to the left of this position and about one to two binocular diameters above the horizon. Start observing 20 minutes after sunset. Since the comet will be seen in twilight, urban versus rural locations are not relevant. A good western horizon and a clear sky are what counts. Recent observations show the comet to be brighter than originally predicted. However, because of sky brightness, its appearance will still be more starlike than comet-like. As the comet pulls away from the sun, it will also be moving southward, favoring the southern hemisphere for best views. See it this week or don't see it at all. More about SOHO at the Planetarium's web site.
091    MAY 24, 1998:   Venus passes Saturn
From the spectacular alignment of the planets that straddled the early night sky of the New Year, the evening sky of May has become bland in comparison—fainter stars and no planets. The Earth's revolution around the sun each year displaces the sun so that in the same time interval the sun travels in a path around the sky through all of the zodiacal constellations. By February, the sun had moved amidst the planetary grouping as vividly witnessed during the total solar eclipse of the 26th. Presently, the sun has traveled far enough to the left of these planets, allowing some of them to once again become visible, but this time in the predawn sky. About 45 minutes before sunrise (5:00 a.m.), you'll find Jupiter "leading" the pack in the east, southeast about 20 degrees in elevation. To the left and about one fist above the horizon, 10 degrees, you'll catch bright Venus (due east) approaching the ringed world of Saturn. Watch these two planets dance. On Thursday morning Venus will be only about two thirds of a degree above and to Saturn's right. Friday finds these planets even closer, about one half degree apart, but Venus has now moved to Saturn's left. Because of the low altitude of this conjunction and Venus' 50-fold brightness advantage over Saturn, binoculars should be used to enhance your views.
092    MAY 31, 1998:   Twilight
With the summer comes an extended period of late sunsets and early sunrises. However, once our day star sinks below the horizon, or before it rises, there is a period of about two hours where the sun's presence can still influences the sky. This period of time is called twilight and it is divided into three basic components: civil, nautical, and astronomical. During civil twilight the sky brightness overwhelms almost all but the brightest stars and planets. Normal outdoor activities can occur without lights. The sun can be as much as six degrees below the horizon. Nautical twilight is the time when sextant navigation can occur. The sky is bright enough to see the horizon easily, but dark enough for viewing the nearly 70 reference stars necessary for fixing your position. The sun is between six and twelve degrees below the horizon. During astronomical twilight, when the sun is between 12 and 18 degrees below the horizon, the limiting brightness of stars at the zenith in a rural setting is sixth magnitude. In the urban Lehigh Valley that's four times fainter than the faintest stars normally visible. Locally on the summer solstice, sunset occurs at 8:36 p.m., civil twilight ends at 9:05 p.m., nautical twilight ends at 9:47 p.m. and astronomical twilight doesn't conclude until 10:36 p.m. Conversely, astronomical twilight begins about 3:28 a.m. as the process begins in reverse. Listen for the birds.
May Star Map

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