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(IAAC) Obj: Abell 4038 (Galaxy Cluster)- Inst: 17.5" f/4.4 dob


Observer: Steve Gottlieb
Your skills: Advanced
Date and UT of Observation: November 1997
Location: Sierra foothills above Jackson, CA, USA (38oN)
Site classification: rural
Limiting magnitude: 6.5
Seeing: 
Moon up: no
Instrument: 17.5" f/4.4 dob
Magnification: 220x, 280x
Filters used: None
Object: Abell4038 (Klemola 44)
Category: Cluster of Galaxies [Abell richness class 2]
Constellation: Scl
Data: mag 13.0 (brightest member)  size 30' (observed)
RA/DE: 23h48m  -28o08m
Description:
Last month I took a look at the galaxy cluster Abell 4038 in Sculptor and was 
surprised to find 11 galaxies within a 30'field.  Although this cluster is not 
well known, it's a cinch to find, with the central core about 15' west of 
naked-eye Delta Sculptoris (V = 4.5).

Four of the members (IC 5350, IC 5353, IC 5354, IC 5358) were discovered by 
Lewis Swift in 1896 observing with a 16" refractor from Echo Mountain above Los 
Angeles while Herbert Howe found IC 5349 a couple of years later from 
Chamberlin Observatory in Colorado with a 20" refractor.  There are several 
faint galaxies (listed in the PGC) which I didn't pick up including PGC 72393, 
72451, 72464, 72473 and 72476 which should be visible in a larger scope or 
better southern horizon.

The following observations were made with a 17.5" f/4.4 at 220x and 280x from 
the Sierra foothills above Jackson, California with a naked-eye limit of 6.5.

Steve Gottlieb
NGC/IC Project
http://www.ngcic.com/ngcic.htm
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IC 5349 = E471-011 = M-05-56-005
23 46 23.0 -28 00 15
V = 14.2;  Size 0.9x0.2;  SB = 12.3;  PA = 20d

very faint, small, elongated 2:1 SSW-NNE, weak concentration.  Required
averted to initially view but with concentration can almost hold
continuously.  Located at the W end of Abell 4038 (first of 11 viewed).
*********************************************

IC 5350 = E471-014 = M-05-56-009
23 47 14.7 -27 57 28
V = 13.4;  Size 0.7x0.6;  SB = 12.5

faint, very small, round, increases to a very small brighter core and
stellar nucleus.  Forms the vertex of an isosceles triangle with a mag 10
star 5' N and a mag 11 star 4.5' ESE. Located about 10' N of the central
core trio IC 5353, IC 5354 and IC 5358.
*********************************************

IC 5353 = E471-017 = M-05-56-010
23 47 28.6 -28 06 33
V = 13.0;  Size 1.4x1.0;  SB = 13.3;  PA = 140d

very faint, fairly small, irregular shape, halo grows in size with averted
vision, weak concentration to a brighter core.  Located in the core with IC
5354 1.6' S and IC 5358 3.9' SE.  A mag 11 star lies 4' NE and a mag 15
star is 1.0' NNE.
*********************************************

IC 5354 = E471-016 = M-05-56-011
23 47 28.6 -28 08 09
V = 14.0;  Size 0.8x0.4;  SB = 12.6;  PA = 66d

extremely faint, very small, round.  A faint companion at the NE edge was
not seen.  Located just 1.6' S of IC 5353 and 3.5' W of IC 5358.
*********************************************

PGC 72437
23 47 43.2 -28 08 38

very faint, very small, nearly stellar nucleus. Forms a close double system
with IC 5358 just 20" between centers!  At moments both cores were clearly
resolved.
*********************************************

PGC 72436
23 47 43.4 -28 10 22

extremely faint, round, 15" diameter.  Glimpsed for moments 2.0' S of IC
5358 in the core of Abell 4038.  Verified on a GSC finder chart and then
reobserved.
*********************************************

IC 5358 = E471-019 = M-05-56-013
23 47 44.2 -28 08 22
V = 12.6;  Size 2.5x1.0;  SB = 13.6;  PA = 122d

initially seen as a single irregular-shaped galaxy but after careful
viewing this double system was resolved into two nearly tangent objects
oriented WSW-ENE (the brighter, larger object to the NE is IC 5358).  At
moments both objects can be seen to have nearly stellar nuclei.  Located
16' W of Delta Sculptoris (V = 4.5).
*********************************************

M-05-56-015 = PGC 72450
23 47 56.1 -28 19 16
V = 14.4;  Size 0.7x0.5;  SB = 13.1

extremely faint, very small, round.  Requires averted to glimpse.  This
difficult member is situated about 12' S of the central group.
*********************************************

PGC 72466
23 48 20.7 -28 13 54

very faint, round, 15" diameter, can hold continuously with averted vision.
Located 2.7' SSE of a mag 11.5-12 star and 10' SE of Delta Sculptoris on
the SE side of the cluster.
*********************************************

PGC 72469
23 48 21.1 -28 06 58

extremely faint, round, 25" diameter, low surface brighness.  Picked up
2.5' SSW of brighter PGC 72471.  Located 7.6' W of Delta Sculptoris
(doesn't interfere with viewing).
*********************************************

PGC 72471
23 48 23.3 -28 04 29

very faint, round, 20" diameter. This faint member was picked up 8' NW of
Delta Sculptoris and 1.2' SSW of a mag 13.5 star and then verified on the
GSC finder chart.  Nearby PGC 72469 lies 2.5' S.
*********************************************