Star Clusters – Page 39 – Astronomy Sketch of the Day

Rocking Horse on the Swan’s Back

NGC 6910, The Rocking Horse Cluster in Cygnus
Sketch and Details by Ferenc Lovró

NGC 6910 (Open cluster)
Also known as: Rocking Horse cluster
Constellation: Cygnus
Right ascension: 20h 24m
Declination: 40° 48′
Seeing: 7/10
Transparency: 4/5
Magnification and filter(s): 250x
Date/time: 2009.06.19 00:00 UT
FoV: 12′
Equipment: 12″ f/5 Newtonian

This tiny little object is also known as the Rocking Horse cluster. The name says it all: it really looks like a little horse jumping around the space. Although it’s in a quite easy position, it still is a neglected object, as when it comes to Cygnus, everyone thinks of nebulae like the Veil and its companions, and the tiny shiny planetaries. Too bad, because this cluster is a real gem! Its special features are the two brightest stars of the cluster (at the front leg and the eye), that are apparently yellow, even though their spectral class suggests a rather white colour. This optical illusion is caused by the interstellar dust that is so common through Cygnus. A very important hint: you should use a fairly high magnification when looking at this object, because it’s located in a field that is rich in bright stars, which makes it harder to detect the real shape of the cluster.

Ferenc Lovró

Onion Like

NGC 6535 Globular Cluster in Serpens
Sketch and Details by Ferenc Lovró

Globular Cluster NGC 6535

NGC 6535 is a tiny, faint globular cluster with four clearly separated stars on its Western side. However, I’m not sure whether they really do belong to the cluster, or they are just plain foreground stars. With several other stars resolved at its slightly brighter core, two of them can be seen clearly with this technique; while some others pop up here and there when the atmosphere calms down for some moments. The core, just like the globular itself is not really sphere-like, but rather looks a little bit like an onion, with the thinner part looking to the East.

Right Ascension: 18h 04m; Declination: -0° 18′
Constellation: Serpens
Date/time: 2009.06.18 21:30 UT
Equipment: 12″ f/5 Newtonian
FoV: 16′ Magnification and filter(s): 250x
Seeing: 7/10 Transparency: 4/5

Location:

Observer: Ferenc Lovró

Antares´s Neighborhood

Rho-Ophiuchi, Antares and M4
Sketch and Details by Leonor Ana Hernández

The view through the binocular was splendid, Antares highlighted with an intense orange and was surrounded by a diffuse cloud, visible with averted vision.

The field was rich, plenty of stars, I distinguished perfectly the cluster M4 as a round nebula of grey cotton. Rho Ophiuchi showed flirt in the upper zone with its three components forming the shape of Mickey Mouse… with a blue intense color. The nebula around Antares appeared to reach Rho Ophiuchi indirectly.

Site : Mazarambroz, Toledo (Spain)
Date : June 20, 2009
Time : 21.53 UT
Binoculars : Vixen 12×80
FOV: 4.2°
Sky brightness : 20.70 magnitudes per square arc second near zenith (SQM reading).
Orientation: N up, E left
Sketch made with graphyte pencil, difumino, on white paper. I scanned it and change to negative view. I added the color tone of the main stars.

Leonor Ana Hernández

Binocular Icon 57 : Sagitta and M71

The Constellation Sagitta and M71 (NGC 6838)
Sketch and Details by Rony De Laet

Sagitta is a small but fascinating constellation. It fits completely in a common pair of binoculars. A fine bonus is offered by the presence of the loose globular, M71. This globular is visible as a hazy spot between Gamma and Delta Sagittae. The object is flanked by two mag 11 stars, one NW of the cluster and one S of the cluster. My 15×70’s shows both Gamma and Delta in one field of view. The whole field gives a great sense of depth. Gamma Sagittae (near the left edge of the sketch) is relatively nearby with a distance of 260 l-y. Delta Sagittae’s distance is about 460 l-y. M71 on the other hand is 13.000 l-y away, hovering at the edge of the galactic plane. From our line of sight towards M71, we probably have to look through a large portion of the dust and gas clouds of the galactic plane. It occurs to me that a lot of M71’s light might be blocked by interstellar absorption.
My choice of binoculars was the 15×70 (compared to my 8×56) to conquer the sky glow of our midsummer nights.

Site : Bekkevoort, Belgium ( 51° N )
Date : June 16, 2009
Time : around 23.30UT
Binoculars : TS 15×70 Marine
FOV: 4.4°
Filter : none
Mount : Manfrotto tripod and head
Seeing : 3/5
Transp. : 2.5/5
Sky brightness : 19.49 magnitudes per square arc second near zenith (SQM reading).
Nelm: 5.3
Sketch Orientation: N up, W right.
Digital sketch made with Corel Paint Shop Pro X2, based on a raw pencil sketch.

(Note: if the sketch does look too dark on your monitor, try to darken the room.)
[click twice on image to see full size sketch]

In the Strings of the Lyre

M56 (NGC 6779) in the constellation Lyra
Sketch and Details by Kiminori Ikebe

M56 (NGC 6779) Globular Cluster in Lyra

This globular is northwest of Albireo. It is a mid-size globular and fairly bright. It is grainy but even at 190x it is not resolved clearly. The center is triangular-shaped with even brightness. The outlying area is faint and diffuse. There are some faint stars further out, but it is not certain whether they are members of this globular.
There is a double star north of the center. The faint outlying area is extensive in the north but almost no extension is detected in the south. However, there is a string of stars forming an arch in the south.

Difficulty level 3
Date of observation: 2000/08/28 00:47
Observing site

M13, with a 4 inch refractor

M13, The Great Globular Star Cluster in Hercules
Sketch and Details by Rony De Laet

M13 has always been one of my all time favourite deep-sky objects. This Globular is one of the summer highlights for Northern Hemisphere observers. It is bright and it is easy to find. When conditions allow, a four inch telescope is capable of resolving many stars within this spectacular globular. The low power view reminds me of little hairy spider. The cluster seems to show several branches attached to a mottled and fractured core. The core appears slightly yellow to me. With higher power and averted vision, these branches can be partially resolved into faint stars. Then with prolonged gazing, the cluster appears to show a few dark lanes as well. It is a hard task to do justice to this cluster with a sketch : the real view is so much more powerful. I tried to represent the typical low power view, with many faint stars at the verge of resolution.

Site : Bekkevoort, Belgium ( 51° N )
Date : May 29, 2009
Time : around 23.00 UT
Scope : Skywatcher 102/500mm achromatic refractor
Eyepiece : Baader Hyperion 5mm
Magnification : 100x
FOV: 41’
Filter : none
Seeing : 3/5
Transp. : 4/5
Sky brightness : 19.88 magnitudes per square arc second near zenith (SQM reading).
Nelm: 5.6
Sketch Orientation: N up, W right.
Digital sketch made with Corel Paint Shop Pro X2, based on a raw pencil sketch.

Rony De Laet

Raining Suculae

Hyades Open Cluster, Melotte-25
Sketch and Details by Math Heijen

On december 27th 2008 I observed the Hyades with my 12×60 Celestron binoculars, mounted on the SkyWindow. The field of view (FOV) that these binoculars provide is about 5 degrees (300′) and the Hyades are just a little to wide, to fit into FOV. But although I didn’t see the whole cluster in one FOV, the first impression of this cluster was simply stunning. The brilliant deep orange Aldebaran, which actually isn’t a member of the Hyades but a foreground star, dominates the field of view, together with three bright yellow companions. These are three of the four yellow giants of the Hyades: Delta, Gamma, and Theta-1. The fourth is Epsilon (which again didn’t fit in the same FOV). There were many different chains of stars and small asterisms (triangles and other shapes) visible. The northern and southern half’s of the cluster seemed to be more or less divided by a dark empty zone, with almost no stars.

Beside Aldebaran and the three yellow stars, there were two other stars that drew my attention. First of all the brilliant white Theta-2 Tauri, with magnitude 3.3 the brightest star, the Lucida of the Hyades. It makes a beautiful double with the Theta-1, one of the yellow giants. To the south of this nice couple I detected the other prominent star, the reddish M-type variable V1146 (or 84 Tauri). In total I counted about between 75 and 85 stars, but I’m sure with my 300mm Dobson I could double or triple that number easily. According to Archinal and Hynes (Star Clusters, Willmann and Bell) the Hyades contain about 380 stars. This makes it a rich cluster. I could not detect any nebulosity of unresolved stars or of any other kind.

This sketch was made with led-pencil on white paper and later processed in Photoshop. The technique used I learned from Jeremy Perez’s website. If you want to learn more about this object or see a few more sketches of open clusters and double stars, please feel free to visit my website at http://www.starobserver.eu

Clear Skies!

Math Heijen

Netherlands

Taking Aim at the Wild Duck Cluster

The Wild Duck Cluster (NGC 6705)
Sketch by Janis Romer, text by Frank McCabe

The Wild Duck Cluster (NGC 6705)

Messier 11 or the wild duck open cluster as it is frequently called is a dense open cluster in the constellation of Scutum. A portion of this cluster is reminiscent of a flock of ducks flying in classic “V” formation. There are nearly 3,000 suns in this cluster, including many giants of all classes. The cluster is estimated to be 250 million years old and like most galactic cluster lies in the plane of the Milky Way.
This cluster was discovered by Gottfried Kirch in 1681 and it was added to Charles Messier’s famous catalog in 1764.
This sketch was made using a Criterion 8” f/8 Newtonian reflector telescope

M 11 (NGC 6705)
Visual mag. 6
Aprox. Distance: 5 kly
Apparent Size: 13 arc min.
RA 18h 51m
Dec – 6° 16′

Stars Like Tiny Pinpoints

M53 (NGC 5024) Globular cluster
Sketch and Details by Kiminori Ikebe, translation by Mr. Eiji Kato

This is a globular cluster southeast of Mel.111 in Coma Berenices. It is fairly large and even at 110x it is finely resolved. This is a beautiful globular cluster with individual stars appearing as pinpoints.
The core shows even brightness and stars are well resolved to the center. North of the center there is a double, but they do not seem to belong to the cluster. The outlying regions in the northern half show scattered faint stars. The southern nebulosity does not show this.

Date of observation: 2000/04/09 02:58 UT
Observing site: Makinoto, Japan
Transparency/seeing/sky darkness: 3/4/4
Instruments: 32cmDB with XL14 at 110x
Width of field: 0.6 °
Kiminori Ikebe

Great Globular

M13, The Great Globular Cluster in Hercules
Sketch and Details by Robert Gudański, commentary by Rich Handy

This beautiful view of M13, the Great Globular Cluster in the constellation Hercules, was rendered by Polish amateur astronomer Robert Gudański. The cluster, some 25,000 light years from Earth, contains hundreds of thousands of stars. It’s been said that the core of M13 is so dense with stars that a planet near the center (assuming a transparent atmosphere), would behold a sky full of bright suns. In fact the sky would perpetually be several times brighter than the full Moon. Not quite the place to be if you like Deep Sky Objects!

M13
Synta 8″ dob
WO UWAN 7
Stepnica, Poland
21.04.2009
Robert Gudański