60 AUSTRALIAN SKY & TELESCOPE November | December 2017
TARGETSESO / IDA / DANISH 1.5M / R. GENDLER AND J.-E. OVALDSEN102 =the halo looks very patchy and
spans about 5v.Viewedwiththe25-cm
scope at 220=,thegalaxy’sunevenly
bright countenance indicates spiral arms
unfolding counter-clockwise. A faint star
anchors the northeastern edge of the
halo.NGC1232Aturnsupasadetached
shredofmistoffthelargergalaxy’seast-
southeastern side. It sits about halfway
betweenandsouthofanimaginaryline
between NGC 1232’s centre and the gold
9th-magnitude star to its east.
Ourquintet’sfinalpartyisNGC 1187,
centred 46vnorthofTau^3 (o^3 )Eridani.It
has fairly low surface brightness, but it’s
nothardtospotthroughthe130-mm
scopeat63=as long Tau^3 is kept out
ofthefieldofview.Thegalaxycovers
roughly 3v= 2 v, and an 8.8-magnitude
star lies off the northwestern tip. NearlyRiver of galaxies
Object Galaxy Type Mag(v) Size/Sep RA Dec.
NGC 1407 Elliptical 9.7 4.6v = 4.3v 3 h 40.2m –18° 35v
NGC 1400 Lenticular 11.0 2.3v = 2.0v 3 h 39.5m –18° 41v
NGC 1393 Lenticular 12.0 1.9v = 1.3v 3 h 38.6m –18° 26v
NGC 1402 Barred lenticular 13.6 0.8v = 0.6v 3 h 39.5m –18° 32v
IC 343 Barred lenticular 13.2 1.6v =0.8v 3 h 40.1m –18° 27v
NGC 1391 Barred lenticular 13.3 1.1v = 0.5v 3 h 38.9m –18° 21v
NGC 1394 Lenticular 12.8 1.3v = 0.4v 3 h 39.1m –18° 18v
NGC 1300 Barred spiral 10.4 6.2v = 4.1v 3 h 19.7m –19° 25v
NGC 1297 Lenticular 11.8 2.2v = 1.9v 3 h 19.2m –19° 06v
NGC 1232 Spiral 9.9 7.4v = 6.5v 3 h 09.8m –20° 35v
NGC 1232A Barred Magellanic spiral 14.6 0.9v = 0.8v 3 h 10.0m –20° 36v
NGC 1187 Barred spiral 10.8 5.5v = 4.1v 3 h 02.6m –22° 52v
NGC 1532 Barred spiral 9.9 12.6v = 3.3v 4 h 12.1m –32° 52v
NGC 1531 Lenticular 12.5 1.3v = 0.9v 4 h 12.0m –32° 51v
Angular sizes and separations are from recent catalogues. Visually, an object’s size is often smaller than the
catalogued value and varies according to the aperture and magnification of the viewing instrument. Right
ascension and declination are for equinox 2000.0.X Interacting galaxies NGC 1532 and NGC
1531 may be difficult to distinguish through
your eyepiece. Use averted vision to locate the
smudge of NGC 1531 on the northwestern edge
of its larger companion.aligned with the halo, a somewhat
brighter, bar-like region inhabits the
interior. At 117= the galaxy wears a
mottled face. The fleecy appearance is
quite pronounced through my 25-cm
reflector at 118=, making NGC 1187
rather pretty. The galaxy grows gentlybrighter toward the centre, and at 171=
I see a slight brightness pip at its heart.
For our finale, let’s swoop down to
the river’s next meander, which shelters
the interacting galaxies NGC 1532 and
NGC 1531, berthed 1.5$ northwest of
Upsilon^4 (p^4 ) Eridani. Through my
105-mm refractor at 17= NGC 1532
is a lengthy band of haze. It looks nice
at 87=, about 6v long with a brighter
elongated interior. A 7th-magnitude
star gleams 13v east-northeast. NGC
1531 is visible with averted vision as
a very faint smudge closely inspecting
the northwestern flank of its much
larger companion, but it shows up
much better at 122=. This is an alluring
duo when viewed through my 25-cm
scope. At 118= NGC 1532’s halo bridges
approximately 9v. The brighter region
is about 3½v long, slightly tilted with
respect to the halo, and it coffers a
small, bright, round core with an
almost starlike nucleus. NGC 1531’s
oval is ¾v long, fairly uniform in surface
brightness, and looks as if it’s taking a
nosedive into its companion.
Deep images show remarkable tidal
tails drawn out of NGC 1532 by the
encounter with its companion. Distance
estimates for this striking pair have
trended upward with time, from as little
as 44 million-light years in the 1980s to
as much as 67 million light-years during
this decade.