[AZ-Observing] Hicksons and Pals
- From: BillFerris@xxxxxxx
- To: az-observing@xxxxxxxxxxxxx
- Date: Sat, 27 May 2006 13:57:21 EDT
Last Tuesday night, the observing conditions at Anderson Mesa were
excellent. Both seeing and transparency were about as good as it gets, here in
northern Arizona, and I took advantage of the primo weather to catch some
photons
with my 18 inch Obsession. Here, are links to my sketches and notes on the
objects.
NGC 5529: _http://members.aol.com/billferris/n5529.html_
(http://members.aol.com/billferris/n5529.html)
Here's an interesting edge-on galaxy. NGC 5529 resides in west-central
Boötes about 4 degrees southwest of 3rd magnitude Gamma (27) Bootis. My sketch
presents a 199X view in the 18-inch Obsession. NGC 5529 is the thin sliver of
light at the center. This 11.9 magnitude spiral covers a 6' by 0'.7 patch of
sky
with that part west of the core appearing brighter than its counterpart to
the east. The core region is slightly irregular in shape, looking like two
small humps on either side of the core. An interesting three-star asterism
stands a few arcminutes to the east. A faint 14th magnitude sparkler simmers
close
by, just off the galaxy's eastern tip. And 1'.7 south of this star is where
PGC 50952 emerges from the night. This 15.3 magnitude spiral presents as a
30" diameter glow. It's very subtle and best seen with averted vision. Even m
ore challenging, is the delicate smudge some 5' to the northwest. That tiny
patch of fog is MCG +06-31-85a, a 16th magnitude galaxy with just the brighter
0'.3 diameter core being visible in the 18-inch. This galaxy is seen
intermittently with averted vision, but always in the same location. This view
is
framed by twenty-five stars scattered throughout the field in my sketch.
Palomar 4: _http://members.aol.com/billferris/pal4.html_
(http://members.aol.com/billferris/pal4.html)
This is among the more challenging Palomar globular star clusters. OK, none
of the them--with the possible exception of Palomar 8--is exactly a showpiece,
but Palomar 4 gives real meaning to the phrase, "faint fuzzy." My drawing
captures a 199X view in the 46 cm (18-inch) Obsession. The field is defined by
the L-shaped collection of stars in the southeast quadrant. 9.8 magnitude SAO
81851 stands just inside the eastern edge of the field. PPM 101191 is the
10.0 magnitude ember near the southern boundary. A 12th magnitude star lies
just north of it. And the feeble point of light at the center of my sketch
shines at 14th magnitude. Palomar 4 is seen as a ghostly haze just to the
southwest of this star. Palomar 4 teases the eye, a 1'.2 diameter gauzy patch
of
light that is only seen with averted vision, but always in the correct
location.
At 18th magnitude, even the brightest residents of Palomar 4 lie beyond the
reach of my scope. More typically, this cluster's stars shine at 20th
magnitude or fainter. Discovered in 1949 by Edwin Hubble, Palomar 4 was
initially
thought to be a nearby dwarf galaxy and was given the moniker, Ursa Major
Dwarf.
However, its status as a distant halo globular of the Milky Way has since
been well-established.
Palomar 5: _http://members.aol.com/billferris/pal5.html_
(http://members.aol.com/billferris/pal5.html)
Here's another very difficult object. With an average surface brightness of
24.7 magnitudes per square arcsecond, very dark skies and excellent
transparency are a must when going after Palomar 5. Discovered in 1950 by
Walter Baade,
astronomers have since found evidence that this cluster is being shredded by
the Milky Way. My sketch presents this carnage as seen at 109X in my 18-inch
(46 cm) Dobsonian. 9.0 magnitude HD 135660 marks the southeast edge of the
cluster. Best seen with averted vision, Palomar 5 emerges northward from this
bright star. The ancient cluster appears as a 7' by 3'.5 oval and is
elongated northwest to southeast. Its mottled appearance and irregular shape
are
nearly unique among the nearly 80 globulars I've observed. It's possible one
or
two of the 15th magnitude stars seen within that feeble glow are cluster
members. The brightest of Palomar 5's stars shine at 15.5 magnitude, well
within
the reach of my scope. As with Palomar 4, this globular was initially thought
to be a nearby dwarf galaxy and Palomar 5 was nicknamed the Serpens Dwarf.
While you're in the area, be sure to check out nearby M5. M5 is truly one of
the magnificent showpieces of the summer sky and it lies just over 2 degrees
north of Palomar 5.
Hickson 70: _http://members.aol.com/billferris/hickson70.html_
(http://members.aol.com/billferris/hickson70.html)
Hickson 70: _http://members.aol.com/billferris/hickson70.html_
(http://members.aol.com/billferris/hickson70.html)
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