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August 2019.

Lunar highlight

Name: Alphonsus

Location: Near the centre of the Moon.

Type: Crater, with a large central peak.

Size: 121 km

Best seen: At First Quarter or six days after Full Moon.

Notes: Named for 13th-century king Alfonso X of Castile. Several tiny, dark-haloed craters can be seen on its floor; these are volcanic vents surrounded by deposits of dark ash. With Ptolemaeus and Arzachel, forms a magnificent trio of craters visible with binoculars.

Deep-sky highlight for August: Ptolemy's Cluster (NGC 6475, Messier 7)

Near the border between Scorpius and Sagittarius and within the main flow of the Milky Way lies a naked-eye nebulous patch, revealed in binoculars as a large, scattered cluster of bright stars. lt was recorded as far back as the second century by the Egyptian astronomer Ptolemy, hence its nickname. La Caille in the 1750s drew attention to the striking linear arrangements of its stars, describing it as a "group of 15 to 20 stars in a square". Other observers comment on the cluster's colourful appearance, noting that several stars are tinted yellow and blue. The accompanying photograph hints at the complex field within which it lies, including the swallow-shaped dark nebula B 287 immediately to the south. For a challenge, try to spot nearby NGC 6453, a globular cluster about one-third of a degree away.

Caption: August 01-15 before sunrise

Caption: August 08-13 after sunset

Caption: August 01-31 evening sky
Celestial almanac

d    Event

01   New Moon (05:12)
     Mars near the Moon
02   Moon at perigee (09:10, 359 397 km)
     Regulus near the Moon
     Callisto at maximum separation from Jupiter
     Titan at maximum separation from Saturn
     Mountain Sanctuary Park Star Party (02-04)
03   Titan at maximum separation from Saturn
04   Callisto at maximum separation from Jupiter
05   Titan at maximum separation from Saturn
06   Callisto at maximum separation from Jupiter
07   First Quarter Moon (19:31)
     ASSA Annual General Meeting
08   Lunar X feature forms (05:43)
     Venus at perihelion
09   National Women's Day
10   Mercury at greatest western elongation (19[degrees])
     Jupiter near the Moon
11   Jupiter stationary
     Titan at maximum separation from Saturn
12   Saturn near the Moon (occultation seen from
     eastern Indonesia, most of Australia, northern
     New Zealand, Polynesia (except Hawaii) and
     Melanesia)
     Moon furthest south (-22.4[degrees])
     Moon at descending node (16:45)
     Uranus stationary
13   Pluto near the Moon (occultation seen from
     north-eastern South America, Ascension
     Island, central and eastern Africa, and
     southern Arabian Peninsula)
     Titan at maximum separation from Saturn
14   Venus at superior conjunction
15   Full Moon (14:29)
     Mercury at ascending node
     Callisto at maximum separation from Jupiter
17   Moon at apogee (12:51, 406 243 km)
     Neptune near the Moon
18   Mars near Regulus
19   Titan at maximum separation from Saturn
20   Mercury at perihelion
21   Uranus near the Moon
     Venus near Regulus
     Callisto at maximum separation from Jupiter
22   Juno at conjuction
23   Last Quarter Moon (16:56)
24   Aldebaran near the Moon
     Venus near Mars (17.4')
25   Titan at maximum separation from Saturn
26   Moon occults eta Gem
     Moon furthest north (+22.5[degrees])
     Mars at aphelion
27   Moon at ascending node (03:50)
     Callisto at maximum separation from Jupiter
     Titan at maximum separation from Saturn
29   Mercury near Regulus
     Callisto at maximum separation from Jupiter
     Titan at maximum separation from Saturn
30   New Moon (12:37) Black Moon
     Moon at perigee (17:59, 357 175 km)
     Mercury near the Moon
     Venus near the Moon
     Mars near the Moon
     Regulus near the Moon
     Mercury at greatest latitude north
     Venus at greatest latitude north

Planet visibility

Mercury can be seen at dawn until late in the
month. Venus and Mars are too near the Sun to be
seen during August. Jupiter and Saturn can be seen
at sunset until before dawn.

Stellar occultations

The Moon occults eta Gem on the morning of
August 26. The table below gives the time of
disappearance (D) and reappearance (R) for
selected locations.

Location          D          R

Harare         03:40:53   04:38:56
Johannesburg   03:56:35   04:21:51

Sun rise and set, position and distance

d    Bloem.          Cape Town       Durban          Harare

     rise    set     rise    set     rise    set     rise    set

01   06:59   17:44   07:39   18:06   06:42   17:23   06:23   17:42
04   06:57   17:46   07:36   18:08   06:39   17:25   06:21   17:43
07   06:55   17:47   07:34   18:11   06:37   17:27   06:20   17:44
10   06:52   17:49   07:31   18:13   06:34   17:29   06:18   17:45
13   06:50   17:51   07:28   18:15   06:32   17:30   06:17   17:45
16   06:47   17:52   07:24   18:17   06:29   17:32   06:15   17:46
19   06:44   17:54   07:21   18:19   06:26   17:34   06:13   17:47
22   06:41   17:55   07:17   18:21   06:23   17:35   06:11   17:47
25   06:38   17:57   07:14   18:23   06:20   17:37   06:09   17:48
28   06:35   17:58   07:10   18:25   06:16   17:39   06:07   17:48
31   06:31   18:00   07:06   18:27   06:13   17:40   06:04   17:49

d    Jo'burg         Declination              Con   Distance
                     at 02:00                       (AU)
     rise    set

01   06:47   17:41   +18[degrees] 12' 27.1"   Cnc   1.015123
04   06:45   17:43   +17 26 31.4              Cnc   1.014730
07   06:43   17:44   +16 38 03.1              Cnc   1.014288
10   06:41   17:46   +15 47 10.5              Cnc   1.013807
13   06:39   17:47   +14 54 01.9              Leo   1.013295
16   06:36   17:48   +13 58 45.6              Leo   1.012759
19   06:33   17:50   +13 01 29.6              Leo   1.012199
22   06:31   17:51   +12 02 22.0              Leo   1.011617
25   06:28   17:52   +11 01 31.2              Leo   1.011007
28   06:25   17:54   +09 59 05.3              Leo   1.010365
31   06:22   17:55   +08 55 13.2              Leo   1.009683

Con = constellation (see Table 11 on p 89), Distance = Sun-Earth
distance in AU. Also see rise/set times on pp 72-73.

Moon rise and set

d    Bloem.          Cape Town       Durban

     rise    set     rise    set     rise    set

01   07:14   18:09   07:57   18:32   06:56   17:48
02   08:06   19:22   08:46   19:48   07:46   18:58
03   08:52   20:31   09:29   20:59   08:33   20:10
04   09:33   21:37   10:08   22:08   09:14   21:17
05   10:12   22:41   10:44   23:15   09:53   22:22
06   10:50   23:44   11:19   -:-     10:30   23:25
07   11:28   -:-     11:55   00:20   11:08   -:-
08   12:07   00:45   12:32   01:24   11:47   00:27
09   12:49   01:46   13:12   02:26   12:28   01:27
10   13:34   02:44   13:55   03:27   13:13   02:26
11   14:22   03:41   14:42   04:24   14:00   03:23
12   15:13   04:34   15:33   05:18   14:51   04:16
13   16:05   05:24   16:26   06:07   15:44   05:06
14   16:59   06:08   17:21   06:51   16:38   05:50
15   17:53   06:49   18:17   07:30   17:32   06:31
16   18:46   07:26   19:12   08:05   18:25   07:08
17   19:38   08:00   20:06   08:37   19:18   07:41
18   20:30   08:32   21:01   09:07   20:10   08:13
19   21:22   09:03   21:55   09:35   21:02   08:43
20   22:15   09:33   22:49   10:04   21:55   09:14
21   23:08   10:05   23:45   10:33   22:49   09:45
22   -:-     10:38   -:-     11:04   23:45   10:18
23   00:04   11:15   00:43   11:39   -:-     10:55
24   01:01   11:57   01:42   12:19   00:43   11:36
25   02:01   12:44   02:44   13:05   01:42   12:23
26   03:01   13:38   03:45   13:59   02:43   13:17
27   04:01   14:39   04:45   15:00   03:43   14:17
28   04:58   15:45   05:41   16:07   04:40   15:24
29   05:51   16:55   06:32   17:19   05:33   16:34
30   06:39   18:05   07:18   18:32   06:21   17:44
31   07:23   19:14   08:01   19:47   07:05   18:54

d    Harare          Jo'burg

     rise    set     rise    set

01   06:34   18:09   07:01   18:07
02   07:29   19:14   07:54   19:18
03   08:21   20:19   08:41   20:25
04   09:08   21:20   09:24   21:30
05   09:52   22:19   10:05   22:33
06   10:36   23:16   10:44   23:34
07   11:19   -:-     11:23   -:-
08   12:03   00:13   12:04   00:34
09   12:48   01:09   12:47   01:33
10   13:36   02:04   13:32   02:31
11   14:25   02:59   14:21   03:27
12   15:16   03:51   15:11   04:20
13   16:08   04:41   16:04   05:10
14   16:59   05:28   16:57   05:55
15   17:50   06:12   17:50   06:37
16   18:39   06:52   18:42   07:15
17   19:27   07:30   19:33   07:50
18   20:15   08:06   20:24   08:23
19   21:02   08:41   21:14   08:55
20   21:50   09:17   22:05   09:27
21   22:39   09:53   22:58   09:59
22   23:30   10:30   23:52   10:34
23   -:-     11:11   -:-     11:12
24   00:23   11:56   00:48   11:54
25   01:20   12:46   01:47   12:43
26   02:18   13:42   02:47   13:37
27   03:18   14:42   03:47   14:38
28   04:16   15:46   04:44   15:44
29   05:13   16:52   05:38   16:52
30   06:06   17:57   06:28   18:01
31   06:55   19:00   07:14   19:08

For Port Elizabeth subtract 28m from Cape Town; for Bulawayo
add 9m to Harare.

Jupiter's Galilean moons

d    Time      Event

02   01:23.6   Europa is occulted
03   19:29.7   Europa transit starts
     21:39.2   Europa's shadow transit starts
     21:56.7   Europa transit ends
04   00:09.4   Europa's shadow transit ends
     19:07.2   Ganymede is occulted
     21:31.4   Ganymede reappears (occulted)
     23:31.5   Ganymede is eclipsed
05   02:03.0   Ganymede reappears from eclipse
     02:45.1   Io is occulted
     19:19.5   Europa reappears from eclipse
06   00:06.4   Io transit starts
     01:12.2   Io's shadow transit starts
     02:18.0   Io transit ends
     03:24.2   Io's shadow transit ends
     21:12.5   Io is occulted
07   00:33.5   Io reappears from eclipse
     18:33.9   Io transit starts
     19:40.9   Io's shadow transit starts
     20:45.5   Io transit ends
     21:52.9   Io's shadow transit ends
08   19:02.3   Io reappears from eclipse
10   21:56.7   Europa transit starts
11   00:15.9   Europa's shadow transit starts
     00:24.1   Europa transit ends
     02:46.4   Europa's shadow transit ends
     22:48.5   Ganymede is occulted
12   01:14.3   Ganymede reappears (occulted)
     21:55.5   Europa reappears from eclipse
13   01:57.1   Io transit starts
     03:07.1   Io's shadow transit starts
     23:03.4   Io is occulted
14   02:28.7   Io reappears from eclipse
     20:24.9   Io transit starts
     21:35.8   Io's shadow transit starts
     22:36.5   Io transit ends
     23:47.8   Io's shadow transit ends
15   19:54.2   Ganymede's shadow transit ends
     20:57.6   Io reappears from eclipse
16   18:16.5   Io's shadow transit ends
18   00:26.1   Europa transit starts
     02:52.8   Europa's shadow transit starts
     02:53.9   Europa transit ends
19   02:33.4   Ganymede is occulted
     19:32.4   Europa is occulted
20   00:31.4   Europa reappears from eclipse
21   00:55.4   Io is occulted
     18:42.7   Europa's shadow transit ends
     22:17.0   Io transit starts
     23:30.8   Io's shadow transit starts
22   00:28.5   Io transit ends
     01:42.7   Io's shadow transit ends
     18:46.4   Ganymede transit ends
     19:23.6   Io is occulted
     21:22.8   Ganymede's shadow transit starts
     22:53.0   Io reappears from eclipse
     23:55.0   Ganymede's shadow transit ends
23   18:56.7   Io transit ends
     20:11.4   Io's shadow transit ends
26   22:03.6   Europa is occulted
27   00:33.0   Europa reappears from occultation
     00:35.3   Europa is eclipsed
28   18:43.3   Europa transit ends
     18:48.7   Europa's shadow transit starts
     21:20.2   Europa's shadow transit ends
29   00:10.1   Io transit starts
     01:25.8   Io's shadow transit starts
     20:12.2   Ganymede transit starts
     21:17.0   Io is occulted
     22:39.7   Ganymede transit ends
30   00:48.4   Io reappears from eclipse
     01:22.2   Ganymede's shadow transit starts
     18:38.6   Io transit starts
     19:54.5   Io's shadow transit starts
     20:50.1   Io transit ends
     22:06.3   Io's shadow transit ends
31   19:17.2   Io reappears from eclipse
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Title Annotation:Alphonsus and Ptolemy's Cluster
Publication:Sky Guide Africa South
Date:Jan 1, 2019
Words:2278
Previous Article:July 2019.
Next Article:Star charts for winter: June 01 at 00:00, July 01 at 22:00, and August 01 at 20:00.
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