[AZ-Observing] Denizens of the Dark

A new Moon and clear skies provided an opportunity to go deep in the night 
sky, this past weekend. Saturday, I observed from a site that gets regular 
use by members of the Coconino Astronomical Society, a picnic area on the 
outskirts of Wupatki National Monument. This site is about 25 miles north of 
Flagstaff. Sunday, I checked out a new observing site, Antelope Park, which 
is a large open space in the heart of the Coconino National Forest about 15 
miles south of Flagstaff.

Both sites offer access to skies that are, for the most part, true dark. The 
picnic area sees skyglow from Flag, to the south. Antelope Park sees Flag to 
the north and the Phoenix (115 miles away) light dome hugs the southern 
horizon. Otherwise, the sky at either location is as dark as it gets.

I'm in the homestretch of the Herschel 400, having observed and sketched all 
but 31 of the list. The majority of these won't be well placed for observing 
in the evening hours until next January, but there were three objects I had 
earmarked for the weekend: NGC 1027, NGC 7686 and NGC 7727. A sampling from 
Eric Honeycutt's list of obscure autumn planetary nebulae completed my 
weekend target list: NGC 6772, NGC 6804 and Jones 1. Oh, and there was one 
late addition: Sharpless 2-86.

I've created webpages, including observation notes and sketches, for each of 
the above and uploaded them to "Cosmic Voyage." You'll find direct access 
through the "NGC/IC Object" menu: http://members.aol.com/billferris/ngc.html

NGC 1027
NGC 1027 is a 6.7 magnitude open cluster. My sketch presents a 129X view in 
my 10-inch, f/4.5 Newtonian. Every star in the drawing is a member of NGC 
1027. The brightest is 7.0 magnitude PPM 13823, centered in the field of 
view. The tight triangle asterism just northwest of PPM 13823 includes stars 
ranging from 11.1 magnitude to approximately 12.5 magnitude. Another 50 stars 
dot the field. NGC 1027 can be found about 6 degrees east-southeast of 3.4 
magnitude Epsilon (45) Cassiopeiae.

NGC 7686
This fine cluster resides in Andromeda, about 3 degrees north-northwest of 
3.9 magnitude Lambda (16) Andromedae. My sketch captures the cluster's 
appearance at 129X. NGC 7686 is anchored by 6.2 magnitude PPM 64311, nearly 
centered in the cluster. About 5' to the west-southwest, 7.7 magnitude PPM 
64297 is seen. Twenty-seven members of this 5.6 magnitude cluster are visible 
across a 14' diameter area. NGC 7686 is framed by an additional 21 stars in 
my drawing.

NGC 7724 & NGC 7727
This duo calls the remote reaches of Aquarius, home. NGC 7724 and NGC 7727 
are stationed near the border with Cetus, 2 degrees due north of 5.0 
magnitude Omega1 (102) Aquarii. My sketch captures the pair at 129X in my 
10-inch Meade Newtonian. NGC 7727, the brighter of the pair, is positioned 
east of center. The 10.6 magnitude SAB-type galaxy features a stellar core 
region, which is embedded within a 4'x3' diffuse glow. This galactic disk 
gradually fades into the background sky. NGC 7727 is aligned roughly 
northeast to southwest and is surrounded by a handful of 12th and 13th 
magnitude stars.

NGC 7724 is visible 12' to the east-northeast. This is a faint wisp of thing, 
mid-13th magnitude and something like 60"x45" in size. It's difficult to make 
size estimates on objects like this, visible only with averted vision and 
already almost lost against the background sky. 10.1 magnitude PPM 241919, 
the brightest star in the field, shines 5'.5 south-southeast of NGC 7724. 
While you're in the area, don't forget to check out NGC 7723 just 43' to the 
south-southwest.

NGC 6772
Planetary nebulae are bizarre objects. The core of a dead star irradiates a 
surrounding envelope of gas. The nebular gases become ionized and, as a 
result, they fluoresce or emit light. These delicate celestial treasures are 
observable for but a few thousand years. Although not brief by human 
standards, that's but a moment in cosmological time. Their appearance can 
vary from highly structured to painfully delicate. NGC 6772 falls somewhere 
in-between. My sketch records a 129X view. An OIII filter improved contrast, 
significantly. The 14.2(P) magnitude planetary is nearly centered. It's oval 
shape covers an 85"x70" area. The 18.6 magnitude central star is not visible. 
However, 27 field stars are. The brightest of these is 9.2 magnitude PPM 
202684, near the northern field edge. The faintest dimly glow at about 14th 
magnitude. NGC 6772 resides 3 degrees northeast of 3.4 magnitude Lambda (16) 
Aquilae.

NGC 6804
This obscure planetary nebula is stationed in Aquila, the eagle, about 5 
degrees west of this constellation's brightest star, 0.9 magnitude Altair. 
Just 35" in diameter, this 12.2(P) magnitude planetary has a high surface 
brightness of about 19.5(V) magnitude per square arcsecond. I was able to 
employ high magnification as a result.

The sketch records a 247X view in my 10-inch Newtonian. That works out to a 
1.0-mm exit pupil, which usually translates to great views of small, high 
surface brightness objects. NGC 6804 lies just south of the center of the 
field. Its 35" diameter form snugs up to 12th magnitude GSC 1055:1669, 
visible against the eastern edge of the planetary. A 13th magnitude GSC star 
is visible another 28" to the east. NGC 6804's 14.3 magnitude central star is 
seen with averted vision, embedded at the center of the nebula. Another 35 
stars dot the field. These include a 12th magnitude sparkler 1'.2 southwest 
of NGC 6804. The brightest field star is 8.9 magnitude PPM 168057, 6' to the 
southeast of the planetary.

Jones 1
Jones 1 is an obscure object. Not many amateur astronomers hunt this elusive 
15.1(P) magnitude planetary nebula. And among those who do seek it out, many 
are foiled in their attempts to make an observation. Of course, the key to 
making such observations is maximum contrast. Observing under the pristine 
dark skies of northern Arizona, I am blessed to have that advantage.

Jones 1 resides in Andromeda just north of the Great Square of Pegasus 
asterism. You'll find it about 7 degrees west-northwest of 2nd magnitude 
Alpheratz. An 18-mm Meade SWA eyepiece fitted with an OIII filter and paired 
with Tele Vue's 3X Barlow produced the view presented in my sketch. The 
planetary is centered in the field. Initially, Jones 1 appears as an 
incomplete annulus. After several minutes, I notice two irregularities in its 
shape. the northern segment appears flattened, even slightly concave. Also, 
the southern portion abruptly terminates where it merges with the slender 
wisp connecting the two brighter segments. No nebulosity along the eastern 
side is visible even after 30-minutes careful observation.

Sharpless 2-86
The NGC identifies this large, diffuse nebula as NGC 6820. However, Albert 
Marth's description, "F,S,R,bM" does not match the large nebulosity 
associated with the galactic cluster, NGC 6823. Astronomer Brian Skiff has 
noted that Marth's position and description do match the small reflection 
nebula, IRAS 19403 +2258, located nearby at 19h 42m 27.9s +23d 05m 15s. 
Therefore, it appears the NGC identification of Sharpless 2-86 as NGC 6820 is 
in error.

My drawing presents Sh2-86 as it appears at low magnification. I used a 
Celestron 23-mm eyepiece, which has an apparent field of 65 degrees and, in 
my scope, produces 49X over a 1.5 degree true field. The nebulosity is quite 
subtle and only mildly enhanced by an OIII filter. Its arcing form is spread 
over roughly a 20'x10' area with the southern portion being discernibly 
brighter. NGC 6823 is visible within the dark region cutting into the nebula 
from the west-northwest. Fifty-one stars are recorded as framework for this 
delicate display. Sharpless 2-86 is found in Vulpecula, 2.5 degrees 
west-southwest of 4.6 magnitude 13 Vulpeculae.

Regards,

Bill Ferris
"Cosmic Voyage: The Online Resource for Amateur Astronomers"
URL: http://www.cosmic-voyage.net
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