·is at a distance of 36 light-years, and ‚, at less than 21
light-years, is even closer. Since ‚is a G-type star, only
21 / 2 times as luminous as the Sun, it may well have a
system of planets, though we have no proof. It is a mere
12 degrees away from the south celestial pole.
Mensais yet another Lacaille creation, originally Mons
Mensae, the Table Mountain. It has the unenviable distinc-
tion of being the only constellation with no star as bright
as the fifth magnitude, but at least a small part of the
Large Magellanic Cloud extends into it.
Chamaeleon. Another dim group. The best way to find it
is to follow a line from ÈCarinae, in the false cross,
through Miaplacidus (‚Carinae) and extend it for some
distance. The four leading stars of Chamaeleon, ·(4.07),
‚(4.26), Á(4.11) and ‰(4.45), are arranged in a diamond
pattern; ‚ lies roughly between Miaplacidus and ·
Trianguli Australe.
Musca Australis, the Southern Fly, generally known
simply as Musca (there used to be a Musca Borealis, in
the northern hemisphere, but this has now disappeared
from our maps; no doubt somebody has swatted it). There
are two bright globular clusters, NGC4833 (C105) near ‰
and NGC4372 (C108) near Á. They are not easy to locate
with binoculars, but are well seen in a small telescope.
Apuswas added to the sky by Bayer in 1603, originally
under the name of Avis Indica, the Bird of Paradise. To
find it, take a line from ·Centauri through ·Circini and
continue until you come to ·Apodis; the other main starsof the constellation – Á, ‰and – make up a small triangle.
‰is a red M-type star, and has a K-type companion at a
separation of 103 seconds of arc. ı, in the same wide field
with ·, is a semi-regular variable which is generally within
binocular range; also in the field is R Apodis, which is
below magnitude five and suspected of variability.
Octanslies nearest to the pole. The brightest star in the
southernmost constellation is Ó, which is a K-type orange
giant 75 times as luminous as the Sun. The south polar
star, ÛOctantis, is only of magnitude 5.5, and is not too easy
to locate at first glance. A good method, using 7-power
binoculars, is as follows:
Identify ·Apodis, as given above. In the same field as
·Apodis are two faint stars, ÂApodis (5.2) and ËApodis
(5.0). These point straight to the orange ‰Octantis (4.3),
which has two dim stars, ^1 and ^2 Octantis, close beside
it. Now put ‰Octantis at the edge of the field, and con-
tinue the line from Apus. ̄Octantis (5.2) will be on the far
side of the field; centre it, and you will see two more stars
of about the same brightness, Ûand È. These three are in
the same field, and make up a triangle. The south polar
star, Û, is the second in order from ‰. Using 12-power
binoculars, the three are in the same field with ̆(5.7).
ÛOctantis is of type F, and is less than seven times as
luminous as the Sun, so that it pales in comparison with
the northern Polaris. The pole is moving slowly away from
it, and the separation will have grown to a full degree by
the end of the century.STAR MAP 22
Hydrus, Mensa, Chamaeleon, Musca, Apus, Octans
BRIGHTEST STARS
Star R.A. Dec. Mag. Spectrum Proper name
hms ° ‘ “
· 01 37 43 57 14 12 0.46 B5 Achernar
ı 02 58 16 40 18 17 2.92 A3A2 Acamar
Also above magnitude 4.3: ̆^4 (3.56), Ê(3.56), ̄(3.70), ̆^2 (3.82), ̆^3 (3.96), Î(4.25), È(4.11),
e(4.27), g (4.27).
DOUBLE
Star R.A. Dec. P.A. Sep. Mags
hm ° ’ ° “
ı 02 58.3 40 18 088 8.2 3.4, 4.5The brightest star is ·; R.A. 04h 14m 00.0s, dec. 42° 17’ 40”, mag. 3.186.
VARIABLE
Star R.A. Dec. Range Type Period Spectrum
hm °’ (mags) (d)
R0 2 53.9 49 53 4.7–14.3 Mira 404 MThe brightest star is ·: R.A. 04h 40m 33s.6, dec. 41° 51’ 50”, mag. 4.45.BRIGHTEST STAR
Star R.A. Dec. Mag. Spectrum Proper name
hms ° ‘“
· 04 34 00 55 02 42 3.27 A0
Also above magnitude 4.3: ‚(3.7 max), Á(4.25).
VARIABLES
Star R.A. Dec. Range Type Period Spectrum
hm °’(mags) (d)
‚ 05 33.6 62 29 3.7–4.1 Cepheid 9.84 F
R0 4 36.8 62 05 4.8–6.6 Semi-reg. 338 M
CLUSTERS AND NEBULAE
M C NGC R.A. Dec. Mag. Dimensions Type
hm ° ’ ’
–05 24 69 45 0 650 550 Galaxy; Large
Cloud of
Magellan
103 2070 05 38.7 69 06 3 40 25 Nebula 30
Doradûs in
Large Cloud
of MagellanBRIGHTEST STARS
Star R.A. Dec. Mag. Spectrum Proper name
hms ° ‘“ ‘
· 04 14 25 62 28 26 3.35 G6
Also above magnitude 4.3: ‚(3.85).ERIDANUSHOROLOGIUMCAELUMDORADORETICULUMBRIGHTEST STARS
Star R.A. Dec. Mag. Spectrum Proper name
hm s ° ‘ “
‚ 00 25 46 77 15 15 2.80 G1
· 01 58 46 61 34 12 2.86 F0
Á 03 47 14 74 14 20 3.24 M0
Also above magnitude 4.3: ‰(4.09), Â(4.11).The brightest star is ·: R.A. 6h 10m 14s.6, dec. 74° 45’ 11”, mag. 5.09.
A small part of the Large Cloud of Magellan extends into Mensa.The brightest star is ·: R.A. 08h 18m 31s.7, dec. 76° 55’ 10”, mag. 4.07.
Also above magnitude 4.3: Á(4.11).BRIGHTEST STARS
Star R.A. Dec. Mag. Spectrum Proper name
hm s ° ‘ “
· 12 37 11 69 08 07 2.69 B3
‚ 12 46 17 68 06 29 3.05 B3
Also above magnitude 4.3: ‰(3.62), Ï(3.64), Á(3.87), Â(4.11).
DOUBLE
Star R.A. Dec. P.A. Sep. Mags
hm ° ’ ° ”
‚ 12 46.3 68 06 014 1.4 4.7, 5.1 Binary; period
many centuries
CLUSTERS AND NEBULAE
MCNGC R.A. Dec. Mag. Dimensions Type
hm ° ’ ’
105 4833 13 00 70 53 7.3 13.5 Globular cluster
108 4372 12 25.8 72 40 7.8 18.6 Globular clusterThe brightest star is ·: R.A. 14h 47m 51s.6, dec. 79° 02’ 41”, mag. 3.83.
Also above magnitude 4.3: Á(3.89), ‚(4.24).
VARIABLES
Star R.A. Dec. Range Type Period Spectrum
hm °’ (mags) (d)
ı 14 05.3 76 48 6.4-8.6 Semi-reg. 119 M
DOUBLE
Star R.A. Dec. P.A. Sep. Mags
hm ° ’ ° “
‰ 16 20.3 78 41 012 102.9 4.7, 5.1The brightest star is Á: R.A. 21h 41m 29s dec. 77° 23’ 24”, mag. 3.76.
The south polar star is Û: R.A. 20h 15m 1s dec. 89° 08’, mag. 5.46.
VARIABLES
Star R.A. Dec. Range Type Period Spectrum
hm °’(mags) (d)
‰ 22 20.0 80 26 4.9–5.4 Semi-reg. 55 MHYDRUSMENSACHAMAELEONAPUSMUSCAOCTANSGb Atl of Univ Phil'03stp 2/4/03 7:44 pm Page 261