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(IAAC) Obj: NGC7232, NGC7233, IC5171, IC5181, NGC7232a (ESO289-003), NGC7232b (ESO289-009) - Inst: 30" f/5 dob



[This is a follow-up to an earlier 'discussion' post on my personal technique
for doing detailed deep-sky logs. Here's the final result of the process which
I described in that earlier post. By the way, my sincere thanks to the Rices,
the kind hosts of New Mexico Skies Inn, for attaching a finder to their fine
30" f/5 dob during my stay there last year - obviously it helped immensely.]
Observer: Lew Gramer
Your skills: Intermediate (some years)
Date/time of observation: 23/24 Sep 2000, 00:00 Local
Location of site: NM Skies Inn, Mayhill NM USA (Lat 33N, Elev 2222m)
Site classification: Rural
Sky darkness: 7.7 <Limiting magnitude>
Seeing: 3 <1-10 Seeing Scale (10 best)>
Moon presence: None - moon not in sky
Instrument: 30" f/5 dob
Magnification: 110x, 175x, 425x, 550x
Filter(s): None.
Object(s): NGC7232, NGC7233, IC5171, IC5181, NGC7232a (ESO289-003), NGC7232b (ESO289-009)
Category: Group of galaxies. External galaxy.
Class: SBa, SABa, SAab, S0, SBab, SBm
Constellation: Gru
Data: mag 12, 13, 13, 12, 14, 14; size 3x1, 2x1, 3x1, 3x1, 2x1, 2x2
Position: 22:15 -45:55
Description:
This fascinating little group of fuzzies was found just at culmination
tonight, low on the Southern horizon right above the nearby ridge line.
The group lies near the W "ankle" of Grus, the Crane, about 3/4 of the
way along a line from wide double Delta Gru to bright white Alpha Gru.
--
Pointing a 50mm finder at this spot, a pretty "finder double" of mag 8
stars appears. Moving up to the dob, the brighter N star (HD210795) is
pale orange and itself a double, and shows itself surrounded at lowest
power (110x) by several somewhat fainter (mag 11-13) stars.
--
NGC7232a (ESO289-003), IC5181:
Just SSW of this golden field star is an apparent spiral, with obvious
E-W elongation. This object showed a fine, tight, bright core at dead
center. Surrounding this were two "brighness steps", or what were most
likely succeeding rings of spiral arms, in the galaxy halo. Suffusing
both "steps" in the halo I often glimpsed what looked like "mottling",
or dark features among the spiral arms. Also observed but not logged,
in both the low- and high-power fields immediately S of NGC7232a, was
the similarly elongated IC5181. Sadly, no detail was logged for i5181.
--
NGC7232, NGC7233:
About 20' ESE of the gold-white finder pair was another, closer pair
of mag 9 yellow stars (HD211111 & HD211121). Surrounding this lovely
pair was another tight, bright little clustering of galaxies. Plying
this group with higher powers (mainly 425x), the brightest appeared
as a nicely E-W elongated spiral (NGC 7232). Lying nearby, to the E
of this bright slice, was a somewhat fainter companion. This smaller
haze (NGC7233) showed a bright, well pronounced core, which also had
a slight E-W elongation. No halo detail was logged, but this *core*
actually displayed two "brightness steps" or distinct isophotes of
its own. Examining images and sketches afterward, it seems likely I
was actually observing the bright irregular bar at n7233's center!
Note that later in the same observation, another look at seemingly
bland NGC7232 revealed some possible additional structure: perhaps
seeing had improved, but suddenly a dark lane could be readily seen
in averted vision, cutting through the center of this spindle. And
occasional glimpses were also noted of stellarings (possibly large
star forming regions?) WNW of the central core. What a lovely pair
these two galaxies must be under Deep Southern skies!
--
NGC7232b (ESO289-009):
Finally, due N of the brighter of the two yellow stars was what at
the time appeared to me as two extremely close galaxies, BOTH with
bright, irregular inner cores and faint outer halos. Interestingly,
though, there is only ONE galaxy cataloged and visible in images at
this spot: it is NGC 7232b (better known as ESO289-009), and it has
the intriguing morphological classification "SBm" - in other words,
a "Magellanic" barred spiral. Also of note, the Hubble GSC catalogs
a "star-like object" (GSC8439-0428) SE of the true nucleus of this
bizarre little galaxy. Looking closely at the Palomar DSS, there is
certainly a wealth of irregular bright spots in this little object:
it seems entirely possible that it truly does appear visually under
these condittions, as a "double" or even multiple galaxy system!
--
IC5171:
Interestingly, the large, bright near-edge-on spiral IC 5171 lying 35'
E of this group was NOT logged this session. A partial reason for this
may have been simple time constraints: the culmination of this group at
this latitude was brief, and the observation not planned ahead of time.
Of course, a scope with a wider field would certainly have brought this
bright sliver to my attention anyway. Sometimes bigger ISN'T better! :)
--
I cannot help but wonder whether this extraordinary Southerly gathering
of galactic smudges is cataloged as a true galaxy group or cluster? But
at least a cursory search of online databases turned up no designations!
In any case, I'll take the liberty of dubbing them "Flamingo's Kids". :)
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