[AZ-Observing] Coma Cluster, JoEr1 and Izzy
- From: BillFerris@xxxxxxx
- To: az-observing@xxxxxxxxxxxxx
- Date: Tue, 14 May 2002 15:38:30 EDT
The last two weekends have offered excellent observing under the dark,
transparent skies of northern Arizona. The following notes are from last
Saturday's session, which took place at the Doney Mountain Picnic Area
located on National Forest Service land near Wupatki National Monument. This
site is a 45-minute drive north of Flagstaff. All observations were made with
a 10-inch, f/4.5 Meade Starfinder equatorial Newtonian. To see my sketches of
the following objects, please click on the hotlinks next to the titles.
COMA GALAXY CLUSTER (http://hometown.aol.com/billferris/n48744889.html )
Few sights are as awe inspiring as seeing a true galaxy cluster. To see a
handful of star cities contained within a single eyepiece field gives one a
sense of both the vastness and the fragility of the universe. The Coma galaxy
cluster, located 2.5 degrees west of 4.2 magnitude Beta (43) Comae Berenices,
lies about 300 million light-years from Earth. MegaStar plots more than 50
galaxies within a 2-degree radius of the brightest members, NGC 4874 and NGC
4889. My observation was made with the Meade 8.8mm UWA eyepiece, which
produces 129x over a 39' diameter field in the Starfinder.
11.6 magnitude NGC 4874 is visible just east of center. Its 2'.5x2'.0 glow is
aligned east-to-west. A 12th magnitude GSC star marks the spot. NGC 4864, a
13.6 magnitude class 2 elliptical galaxy, is glimpsed some 5' to the east.
PPM 102294 stands 6' to the north of NGC 4874. PPM 102295 is another 10' to
the north. Two faint galaxies are visible northeast of PPM 102294. The first,
lying 3' from the 7.2 magnitude star, is NGC 4865. NGC 4860 lies another 4'
along the same line. Both weigh in at a scant 13.6 magnitude.
NGC 4889, an 11.5 magnitude elliptical galaxy, casts a soft glow just 7' west
of NGC 4874. Its 2'.0x1'.5 form is arranged along a northwest-southeast line.
13.5 magnitude NGC 4898, 2'.5 to the WSW, blinks in-and-out with averted
vision. IC 4051 is a 13.2 magnitude elliptical galaxy standing 10' west of
NGC 4874.
Finally, three galaxies are gathered along the northwest field boundary.
These include 13.6 magnitude NGC 4881, which lies 5'.5 west of 8.2 magnitude
PPM 102295. NGC 4885 is a 13.2 magnitude SO-type galaxy positioned 5' WSW
from NGC 4881. Just inside the northwest field boundary with a 12th magnitude
GSC star stuck in its side is NGC 4907, a 13.5 magnitude stellar metropolis.
This field presents a good deep-sky challenge for observers with moderate
aperture under very dark skies, or large aperture under typical rural or
suburban skies.
JONES-EMBERSON 1 (http://hometown.aol.com/billferris/pk164311.html )
This large, faint planetary nebula is as much a test of your observing site
as it is of your observing skills. Don't expect to see Jones-Emberson 1 under
light-polluted skies with any aperture. But under the dark, transparent skies
of northern Arizona, this gossamer cloud is visible in my 10-inch Newtonian.
My observation was made at 63x.
Jones-Emberson 1's location is marked by a four-star asterism, which looks
something like a backwards rendition of Corvus, the crow. This grouping
stands just east of the planetary. Close inspection reveals the northwest
corner star of the grouping to be a triple. The star at the southwest corner
is 9.1 magnitude PPM 31412.
Jones-Emberson 1 (JoEr 1) is visible with the aid of a UHC or OIII filter.
While the nebula remains unchanged when switching between the two, the UHC
does show slightly fainter stars. The planetary's 6' diameter glow appears
uniform and without detail in my 10-inch. Larger scopes reveal bright knots
within an annulus. A 13th magnitude GSC star peaks through the nebulosity
along the northern edge of JoEr 1, with an 11th magnitude GSC star another 6'
to the NNW. 9.0 magnitude PPM 31381 stands sentry to the north. Look for JoEr
1 about 2.5 degrees northwest of 4.8 magnitude 27 Lyncis.
IZZY (http://hometown.aol.com/billferris/ikzhang051202.html )
Comet Ikeya-Zhang continues to put on a fabulous display. Last Saturday
night, the comet was in Hercules cruising near the zenith. I caught up with
Ikeya-Zhang using a 32mm TeleVue plossl, which presents a 1.4 degree true
field at 36x in my 10-inch.
Izzy's coma was large and bright, some 22' in diameter. The pseudo-nucleus
appeared bright and slightly elongated along a north-south axis. The western
portion of the coma was brighter than its counterpart and a gossamer tail
reached beyond the field horizon to the south. This tail extended at least
another full eyepiece field in length, which made it about 2.5 degrees long.
Averted vision suggested the presence of a second tail extending to the SSE
from the eastern half of the coma. This ghostly veil faded away by the time
it reached the field boundary.
Regards,
Bill Ferris
"Cosmic Voyage: The Online Resource for Amateur Astronomers"
URL: http://www.cosmic-voyage.net
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