Category: Star Clusters

Bejeweled Ink Spot

NGC 6520 and Barnard 86

NGC 6520 and Barnard 86
Sketch and Details by Kiminori Ikebe

A dark nebula telescopically easy and an beautiful overlapping open cluster. A photograph taken by a 200mm lens shows a small dark nebula and a compact open cluster at the southern edge in addition to M8 and M20. At 110x B86 is quite clear. The field is lit up by the Milky Way stars but a dark triangular shape region to the west of NGC 6520 is quite conspicuous. It appears as if the area is literally painted black and is called the “Ink Spot.” A line of stars along the base of this triangle. A hint of a long dark nebula to the southwest of NGC 6520. This is not as conspicuous as B86; not visible with direct vision. NGC 6520 is beautiful, compact, and “lively.” Bright stars are scattered across. Faint stars are concentrated in some areas.

Milky Way Sights

Lagoon Nebula and Vicinity

Lagoon Nebula and Vicinity
Sketch and Details by Carlos Hernandez

My South Florida weather cleared temporarily on July 30, 2008 (04:00 U.T.) and allowed me to tour the Milky Way with my Oberwerk 11 x 56 binoculars. Many targets were visible but the Lagoon Nebula (M8) and Trifid Nebula (M20), as well as M21 and M28 caught my eye. The Lagoon Nebula (M8, NGC 6523) was visible as an elongated nebulosity which included clumps of stars (NGC 6530). The Trifid Nebula (M20, NGC 6514). The open cluster M21 was visible north of the Trifid Nebula and M28 towards the east (left).

A digital rendering made using Photoshop CS3.

Carlos

Sagitta’s Stellar Nexus

M71

M71
Sketch and Details by Ernest Shekolyan

Hi!

That is my picture of M71 (globular cluster NGC 6838 in Sagitta 8.4m, 7.2′).
The sketch was done 27 July 2006 at village Ponizovka, South Crimea (Ukraine) under very dark sky (visual limit for naked eye was better 6.1m). 10″ 1:5.6 Dob, 6 mm UWA (Synta), 230x, FOV: 20 ang. minutes, graphite pencil, white paper, then photocopy + level correction, crop and inverting in ACDSee.

Sincerely yours, Ernest Shekolyan

Riches of the Star Queen

M16

M16 – The Eagle Nebula
Sketch and Details by Eric Graff

Object Name: Messier 16
Also Known As: NGC 6611, Cr 375, Mel 198, C1816-120, IC 4703, Sh2-49, Eagle Nebula, Star Queen Nebula
Object Type: Open Cluster + Emission Nebula + Dark Nebula
Constellation: Serpens (Cauda)
Right Ascension (2000.0): 18h 18m 45.0s
Declination (2000.0): –13° 47′ 54"
Magnitude: 6.0
Size: Cluster 21′; Nebula 35′ x 28′
NGC Description: Cl, at least 100 st L & S
Discovery: Philippe Loys de Chéseaux, 1746

Date/Time: 4 July 2008 • 04:20 to 06:45 UT
Location: Oakzanita Springs (4,010 ft. elevation), San Diego Co., California, USA
Telescope: Parks Astrolight EQ6 • 6" f/6 Newtonian Reflector
Eyepiece/Magnification: Parks 15mm Gold Series Plössl • 60x • 52′ FoV
Filters: Lumicon OIII
Conditions: Clear, calm, 62°F
Seeing: Pickering 4-5
Transparency: NELM 6.3; TLM 14.0

The Eagle Nebula (or the Star Queen Nebula, if you prefer) is one of the most spectacular "Great Nebulae" in the sky – in photographs, anyway. Unlike other emission nebulae on Messier’s list (M8, M17, M20, and M42-43), the Star Queen does not willingly yield her secrets to the visual observer. In fact, she puts up a rather tenacious fight.

The sky was not quite wholly dark when I centered my scope on M16 soaring above the brink of Oakzanita Peak. The nebulosity itself was not visible yet, but I immediately set to work sketching the visible members of the bright and easy open cluster invested in the nebula. By the time this task was completed the sky had darkened completely as the billowing clouds and star-studded reaches of the Milky Way cast their net above the entire eastern horizon. In the eyepiece gossamer veils of tenuous nebulosity draped lazily over the sparkling star cluster like a lumpy, disheveled cloak.

The best view in my scope occurs at 60x magnification with an OIII filter. The nebulosity is complex and the hazy morass dances with subtle possibilities, but getting that detail onto paper was challenging; the region around the famous "Pillars of Creation" was particularly difficult in this regard. Once I was satisfied that I had done all I could with the central portion of the nebula I was able to pick up faint, nearly featureless extensions on nearly every side by placing the cluster just outside the field of view and sweeping slowly from side to side (N-S or E-W; kind of like looking for the tail of a comet).

Globular Cluster NGC 6934 in Delphinus

NGC 6934

NGC 6934
Sketch and Details by Frank McCabe

Globular cluster NGC 6934 is an 8.9 magnitude ancient sphere of thousands of stars in the constellation of Delphinus. It is situated in a nice star rich region of the constellation at R.A. 20 hrs. 34 min. and Dec. +7° 24’. This globular can easily be located by star hopping. Begin at Beta Delphini and move through and past Eta Del. to Epsilon Del. Now extend this arc distance an equivalent length beyond Epsilon Del. And you will arrive at NGC 6934. To my eyes the diameter appeared to be about 5 arcmin. At 52,000 light years most of the brightest stars of this globular fall between 14th and 15th magnitude. I was able to detect granularity at the core but a scope larger than 10 inches would be best for resolving stars in this cluster. This globular is worth a look.

Sketching:
9”x11” white sketching paper; 6B, 4B, HB graphite pencils and a blending stump;
Scanned and inverted; brightness of some stars adjusted with MS Paint.
Scope: 10” f/5.7 Dobsonian: 24 mm widefield eyepiece 60x and 12 mm eyepiece 121x
Date and Time: 7-23-2008, 7:00-7:30 UT
Seeing: Pickering 7/10
Transparency: Average 3/5
NELM: 4.4

Frank McCabe

Line of Sight Neighbors

M39

M39 and NGC 7082
Sketch and Details by Rony De Laet

The brightest open cluster of Cygnus is Messier 39. With a diameter of more than a full moon, M39 is a beautiful binocular object. To find this open cluster, just drawn an imaginary line from Deneb (Alpha Cygni) to Alpha Lacerta and point your binoculars at the middle of that line. There you’ll find M39 as a large triangular configuration of 6 brighter stars with a dozen fainter ones. While you have this open cluster in your sight, try to find a neighbour of M39: NGC 7082, at one and a half degree to the south. NGC 7082 is rather dim, compared to M39. My binoculars show only a few faint stars in an elongated misty patch of weak unresolved star glow. M39 and NGC 7082 appear to be close companions, but this an optical illusion. While M39 is 830 light-years from us, NGC 7082 is about 5 times further away. With both objects in the field of view, it is not difficult to imagine that NGC 7082 floats far behind M39 through the night sky.

Site : Bütgenbach, Belgium
Date : July 1, 2008
Time : around 23.45 UT
Binoculars : Bresser 8×56
FOV: 5.9°
Filter : none
Mount : Trico Machine Sky Window
Seeing : 3,5/5
Transp. : 4/5
Nelm : around 5.8
Sketch Orientation : N up, W right.
Digital sketch made with Photo Paint, based on a raw pencil sketch.

(Note: if the sketch does look too dark on your monitor, try to darken the room.)

Binoculars Along the Spine of the Scorpion

Antares, M4, & Rho Oph
Antares, M4, and Rho Ophiuchi
Sketch and details by Michael Rosolina

Scorpius is well placed right now for northern hemisphere observers and holds many beautiful and interesting objects. Scanning the constellation with widefield binoculars can be particularly rewarding. I found that I could see this trio all at the same time with my 15×70 binoculars. They make an interesting combination: Antares, a red giant, Rho Ophiuchus, a bright binocular triple, and Messier 4, a globular cluster containing countless stars.

The sketch was done in the field with 2B and HB pencils and a stump loaded with 4B graphite for M4. I then scanned and inverted the sketch digitally, colorised Antares, and added a little blur (5%).

There are many images of this region–time exposures showing the stars embedded in glowing clouds of gas and dust. None of that can be seen visually, but the binocular view has its own beauty.

Michael Rosolina
Friars Hill, WV USA

Marbled Milky Way Magesty

NGC 6604
NGC 6604
Sketch and details by Eric Graff

Object Name: NGC 6604
Also Known As: H.VIII.15, Cr 373, C1815-122
Object Type: Open Cluster + Emission Nebula (Sh2-54)
Constellation: Serpens (Cauda)
Right Ascension (2000.0): 18h 18.0m
Declination (2000.0): –12° 14′
Magnitude: 6.5
Size: 6′ (some sources say 60′)
NGC Description: Cl, lRi, lC
Discovery: William Herschel, 15 July 1784

Date/Time: 4 July 2008 • 09:05 to 10:30 UT
Location: Oakzanita Springs (4,010 ft. elevation), San Diego Co., California, USA
Telescope: Parks Astrolight EQ6 • 6″ f/6 Newtonian Reflector
Eyepiece/Magnification: Parks 15mm Gold Series Plössl • 60x • 52′ FoV
Filters: Lumicon UHC, Lumicon OIII
Conditions: Clear, calm, 62°F
Seeing: Pickering 4-5
Transparency: NELM 6.3; TLM 14.0

If you sweep 1.6° north and slightly west of M16 you’ll chance upon a tight knot of five stars in a glittering field awash with hundreds of stars and marbled with complex swirls of bright and dark nebulosity. This small group (and undoubtedly many of the fainter stars that surround it) comprises the open cluster NGC 6604. The nebulosity (which I found remarkably easy to detect, even without filters) is the southernmost section of a large, but faint, HII region catalogued as Sh2-54. The 7th magnitude lucida of NGC 6604 is an O8 type star that is also an eclipsing binary (of the Beta Lyrae type) designated MY Serpentis. In spite of its spectral type, MY appears yellowish in the eyepiece; this is because the cluster (and nebulosity) is buried deeply in the Great Rift of the Milky Way, severely dimming and reddening its light.

In order to concentrate on the nebula itself, Eric notes: “I sketched the object(s) and a couple dozen of the brightest field stars and background nebulosity. Then, due to the extreme richness of the field I got out printed DSS negatives and started circling the stars I could see (which still took a fair amount of time). These were transferred to the sketches over the weekend. “