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October 2019.

Lunar highlight

Name: Plato

Location: Near the Moon's northern limb, sunk about 2 km deep into the western heights of the lunar Alps.

Type: Crater, with a dark floor.

Age: About 3.6 billion years.

Size: 104 km

Best seen: One day after First Quarter and at Last Quarter.

Notes: Five small craters are scattered across Plato's floor; all traces of its original central elevations have been wiped out by later lava flows. Transient lunar phenomena have been reported within Plato.

Deep-sky highlight for October: The Cartwheel Globular (NGC 6752)

Located in the northern part of Pavo the Peacock, this magnificent cluster can be seen with the naked eye as a 5th-magnitude glow. Binoculars show it to be one of the gems of the sky, revealing an impressive blaze of light, with stars spilling out over an area at least four arcminutes in diameter. It has a very broad centre with a much less prominent outer fringe. A bright star (7th-magnitude HD 177999) lies near its edge to the south-west.

Even a small telescope shows individual stars scattered across its disc--the brightest members are about magnitude +10.5 and have a reddish tinge.

A moderate-sized telescope under dark skies shows the cluster at around 20 arcminutes in diameter, as the stars on the horizontal branch begin to fill in the view. HD 177999 is now located well within the halo. A closer look at this star reveals it to be an unequeal double, its 9th-magnitude companion located less than three arcseconds away.

The nucleus is revelaed as a tight, one arcminute, bright knot of irregular shape, likened to a banana by some. Look out for the remarkable crooked lines of stars radiating from the cluster's centre, which inspired Magda Streicher to compare it to a cartwheel. Curiously, the cluster's stars appear to be of two distinct magnitudes, with the fainter stars near the centre, creating the illusion of an object within an object.

South African comet hunter Jack Bennett included it as No. 121 in his catalogue of comet-like objects, a southern-hemisphere version of the Messier catalogue.

The Cartwheel lies some 13 000 light years away and is about 13 billion years old. (Sketch by Magda Streicher as seen through her 16-inch SCT.)

Caption: October 01-31 after sunset

Caption: October 01-06 after sunset

Caption: October 29-31 after sunset
Celestial almanac

d    Event

01   First day of school term 4
02   Callisto at maximum separation from Jupiter
     Pluto stationary
03   Jupiter near the Moon
     Mercury at aphelion
04   World Space Week (04-10)
     Venus near Spica
05   First Quarter Moon (18:47)
     Moon furthest south (-22.8[degrees])
     Moon at descending node (20:49)
     Saturn near the Moon (occultation seen from
     southern Africa, Easter Island, southern South
     America, and South Georgia)
     Titan at maximum separation from Saturn
06   Lunar X feature forms (06:17)
     Pluto near the Moon (occultation seen
     from Australia, Melanesia, south-eastern
     Micronesia, and western Polynesia)
     Titan at maximum separation from Saturn
09   Moon occults gamma Cap
     Callisto at maximum separation from Jupiter
10   Moon at apogee (20:30, 405 901 km)
     Callisto at maximum separation from Jupiter
11   Neptune near the Moon
12   Callisto at maximum separation from Jupiter
     Titan at maximum separation from Saturn
13   Full Moon (23:08)
14   Titan at maximum separation from Saturn
15   Uranus near the Moon
17   Aldebaran near the Moon
19   Callisto at maximum separation from
     Jupiter
20   Moon furthest north (+22.9[degrees])
     Moon at ascending node (09:28)
     Mercury at greatest eastern
     elongation (25[degrees])
     Callisto at maximum separation from
     Jupiter
21   Last Quarter Moon (14:39)
     Pollux near the Moon
     Titan at maxiumum separation from
     Saturn
22   Titan at maximum separation from
     Saturn
23   Regulus near the Moon
     Mercury at greatest latitude south
     Titan at maximum separation from Saturn
25   Venus at descending node
26   Moon at perigee (12:42, 361 314 km)
     Mars near the Moon
27   Callisto at maximum separation from Jupiter
28   New Moon (05:38)
     Callisto at maximum separation from Jupiter
     Uranus at opposition
29   Venus near the Moon
30   Mercury near Venus
     Titan at maximum separation from Saturn
31   Dark Matter Day
     Jupiter near the Moon
     Mercury stationary

Planet visibility

Mercury and Venus are prominent in the evening
sky this month. Mars can be seen in the morning
sky late in the month. Jupiter and Saturn can be
seen in the evening sky.

Stellar occultations

The Moon occults gamma Cap on the morning of
October 09. Predicted time of disappearance for
selected locations are: Bloemfontein (02:44:57),
Cape Town (02:38:13), Durban (02:43:24) and
Johannesburg (02:48:18).

Occultation of Saturn

The Moon occults Saturn on October 05. The table below
gives the times of first contact (A- D) and last contact (E--H)
of the rings (A, D, E, H) and planetary limb (B, C, F, G), with
the Moon. Also see the diagram on p 19.

     Bloem.    Cape Town    Durban     Harare    Jo'burg

A   21:42:34   21:35:15    21:46:02   21:48:37   21:44:10
B   21:42:59   21:35:42    21:46:27   21:48:58   21:44:34
C   21:43:42   21:36:30    21:47:16   21:49:30   21:45:13
D   21:44:06   21:36:57    21:47:41   21:49:51   21:45:37
E   22:28:59   22:22:06    22:23:30     ----     22:33:34
F   22:29:11   22:22:18    22:23:39     ----     22:33:47
G   22:29:48   22:23:00    22:24:22     ----     22:34:21
H   22:30:00   22:23:11    22:24:31     ----     22:34:34

Sun rise and set, position and distance

d    Bloem.          Cape Town       Durban          Harare

     rise    set     rise    set     rise    set     rise    set

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

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

01   05:48   18:07   -02[degrees] 52' 53.1"   Vir   1.001439
04   05:45   18:09   -04 02 37.5              Vir   1.000562
07   05:41   18:10   -05 11 55.4              Vir   0.999679
10   05:38   18:12   -06 20 37.1              Vir   0.998799
13   05:35   18:13   -07 28 32.8              Vir   0.997930
16   05:32   18:15   -08 35 33.0              Vir   0.997076
19   05:29   18:16   -09 41 27.9              Vir   0.996239
22   05:27   18:18   -10 46 07.7              Vir   0.995418
25   05:24   18:20   -11 49 22.3              Vir   0.994607
28   05:22   18:22   -12 51 00.6              Vir   0.993800
31   05:19   18:24   -13 50 51.4              Vir   0.992996

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

d    Harare          Jo'burg

     rise    set     rise    set

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

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

Jupiter's Galilean moons

d    Time      Event

01   18:43.7   Io's shadow transit ends
04   19:05.0   Ganymede transit ends
     21:18.2   Ganymede's shadow transit starts
     23:57.4   Ganymede's shadow transit ends
06   18:52.3   Europa transit starts
     21:14.8   Europa's shadow transit starts
     21:24.2   Europa transit ends
     22:48.4   lo transit starts
     23:49.1   Europa's shadow transit ends
     23:57.6   Io's shadow transit starts
07   19:58.5   Io is occulted
     23:23.7   Io reappears from eclipse
08   18:26.3   Io's shadow transit starts
     18:40.2   Europa reappears from eclipse
     19:30.1   Io transit ends
     20:38.6   Io's shadow transit ends
11   20:44.1   Ganymede transit starts
     23:20.6   Ganymede transit ends
13   21:37.5   Europa transit starts
14   21:57.7   Io is occulted
15   19:16.5   Io transit starts
     20:21.0   Io's shadow transit starts
     21:15.4   Europa reappears from eclipse
15   21:28.8   Io transit ends
     22:33.5   Io's shadow transit ends
16   19:47.9   Io reappears from eclipse
22   19:15.5   Europa is occulted
     19:26.0   Ganymede is eclipsed
     21:15.6   Io transit starts
     22:10.1   Ganymede reappears from eclipse
     22:15.7   Io's shadow transit starts
23   18:27.5   Io is occulted
     20:26.1   Callisto reappears from eclipse
     21:43.3   Io reappears from eclipse
24   18:25.3   Europa's shadow transit ends
     18:57.1   Io's shadow transit ends
29   19:38.7   Ganymede is occulted
     22:00.3   Europa is occulted
     22:20.6   Ganymede reappears (occulted)
30   20:28.1   Io is occulted
31   18:27.3   Europa's shadow transit starts
     18:38.9   Io's shadow transit starts
     19:11.0   Europa transit ends
     19:58.0   Io transit ends
     20:51.9   Io's shadow transit ends
     21:03.6   Europa's shadow transit ends
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Title Annotation:Plato and Cartwheel Globular
Publication:Sky Guide Africa South
Date:Jan 1, 2019
Words:2333
Previous Article:September 2019.
Next Article:November 2019.
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