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(IAAC) Obj: Abell 262 (Galaxy Cluster) - Inst: 20" f/5 dob newt


Observer: Lew Gramer
Your skills: Intermediate
Date and UT of Observation: 1997-11-04/05, 04:30 UT
Location: Miles Standish State Forest, MA, USA (41N, elev 30m)
Site classification: rural
Limiting magnitude: 6.9 (zenith)
Seeing: 4 of 10 - above average
Moon up: no
Instrument: 20" f/5 Tectron truss-tube dob Newtonian reflector
Magnification: 70x, 210x, 420x
Filters used: None, DeepSky
Object: Abell262
Category: Cluster of galaxies (richness 0, morphology Irreg)
Constellation: And (border with Tri)
Data: mag 12 (brightest gx)  size 120'x120' (catalog)
RA/DE: 01h53m  +36o09m
Description:
Tonight's observing session became the Night of the Galaxy Fields,
as Steve Clougherty and myself swung from one Abell cluster, non-
Abell cluster, or galaxy group to another. The second target Field
of the night was Abell 262, a faint but complex galaxy cluster in
George Abell's famous catalog, which hesitates near Andromeda's S
border with Triangulum. This is generally a very interesting area
for deep sky observing. Several nice galaxy groups lie just a few
finder fields away, including the challenging A347 and Hickson 10.
A262 does seem like a tough target for smaller scopes, with 3 or
even fewer members visible to scopes below the 12" range.
--
The field of A262 is not too hard to find, lying about 2o straight
SW of the bright, famous open cluster ngc 752. Sweeping from this
gorgeous wide-angle star field past the bright loose grouping of
stars around orange 56 And, the finder encounters a degree or so
of relative emptiness before happening on the field. If you hit a
mag 7 star (HD 11202) you've gone too far! Telrad jockies like me
can also use the fact that A 262 is in pretty close line with delta
and beta Tri (don't confuse delta with gamma nearby!), about 4o NW
of beta, and is also collinear with more distant epsilon and 6 Tri.
--
  ngc 710       mag 13.7        size 1.3'x1.2'  type Sc
One of the brightest members of 262, n710 was actually difficult at
first glance to distinguish from the stars in the field. At 70x, it
was directly visible but not striking. Even at 210x, the tiny core
looked similar to the many soft star images in the field. However,
a closer look at 210x and especially 420x confirms its fuzzy nature.
In fact although the core was featureless, a hint of mottling could
be ferreted from the halo with averted and concentrated vision. An
object possibly worth another view later, using a larger aperture?
[Also an interesting desk-note: 710 is listed as a member of A262,
but this struck me as strange, considering the gas-poor nature of
most of the other members, and 710's 'Sc' morphology. Sure enough,
710 has recession velocity 6110 vs. Rv's of 4300 to 4900 for the
other galaxies in this log: it seems that 710 is a field galaxy!]
--
  ngc 708       mag 14.8p       size 3.0'x2.5'  type E
Readily found in a tight clustering with fainter n705 and n703
(see below) inside a very small space. This was the most easily
visible object in the cluster, and was the "locator object" for
it. An essentially round object with no more than 2 or 3 "steps
of brightness" from its hazy halo to its bright, broad core. It
lies inside the N vertex of a pretty triangle of mag 10 stars.
--
  ngc 705       mag 14.6p       size 1.2'x0.2'  type S0asp
The faintest member of the tight central trio of A262. Despite its
faintness, this tiny haze is hard to miss with averted vision, as
it is a distinctive (but featureless) spindle, raying E-W out of a
much brighter oblong core, oriented almost perpendicularly N-S.
--
  ngc 703       mag 13.3        size 1.2'x0.9'  type S0
Although n703 is the middle child of this cluster's central trio
(with n708 and n705 above), it is actually the last I saw. It is
fairly bright in the center, with a complexly-shaped core seeming
to be elongated both E-W and yet more N-S. The halo however seemed
round & featureless, and no hint of arms or mottling could be seen.
--
  ngc 704       mag 14.1p       size 0.6'x0.6'  type E
This is actually a symbiotic pair of galaxies, appearing unusual
in photographs. Tonight though, I could distinguish only one core.
It was however somewhat irregular, appearing slightly brighter to
the N. Aside from this hazy core, no brightness steps were seen.
--
  ngc 714       mag 13.1        size 1.6'x0.4'  type S0asp
Although in photographs, this edge-on spiral and its near neighbor
n717 (compare below) appear almost like bookends, they are in fact
visually quite distinct. 714 is readily visible within a widefield
view of the trio 708/5/3, showing a bright roundish core to direct
vision, with only a hint of an E-W elongated halo in averted vision.
At 420x there was a mere impression of some complexity in the core.
--
  ngc 717       mag 13.9         size 1.3'x0.3'  type S0asp
n717, in contrast to its "bookend" neighbor n714 (above), is only
visible to averted vision, a few arcminutes further E than 714 from
the cluster's center. It is a line of haze aimed NW-SE, and largely
featureless, although a faint uneven bar was noted (possibly just a
star involved SE of the indistinct central core).
--
  ugc 1332      mag 14.6p        size 1.8'x1.6'  type E
Found accidentally while sweeping for ngc710 (above). This faint
elliptical was only distinguishable from nearby stars to averted
vision by noting its slight elongation N-S.
--
Some objects looked for and NOT seen tonight: n700, n709, ugc 1319.
--
This was (as usual) just a cursory look at all the fuzzies that MAY
have been found within a few wide eyepiece fields of the center of
this distant galactic hive. But yet MORE galactic groupings of the
distant universe awaited us tonight, so I hurried on after only a
half hour. Maybe A262 will be worth a more lasting look later on...
Maybe in one of those (yet) larger Monster Eyes that haunt desolate
fields in New England on moonless nights!