rodelaet
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Reged: 04/28/06
Posts: 3063
Loc: 50°56' N - 4°58' E (Belgium)
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Binocular Icon 51: Cassiopeia OB8
Cassiopeia is a very interesting Autumn and Winter constellation. This constellation has many deep-sky targets to offer. Even without a star chart, chances are that you run into several open clusters while scanning that part of the Milky Way with a pair of binoculars. One of the most enjoyable star fields can be seen near Delta and 44 Cassiopeiae. Here you will find a few members of the so called Cassiopeia OB8 Association: M103, NGC663, NGC654 and NGC 659. All these clusters can be seen in one single field of view. The OB8 association is thought to be 20 to 25 million years old and 9.200 l-y away. For the easy of orientation in this crowded window of our home galaxy, I included a labelled sketch in the second post. M103 can be found at 1° ENE of Delta Cas. It is a rather compact and inconspicuous streak of light. Only 3 stars are visible. Continue for another 1,5° further away from Delta and you’ll encounter NGC 663. At first, I noted two pairs of brighter stars at the N edge of a triangular patch of light. With averted vision, more fainter stars can be resolved. A dark lane, running from N to S through the cluster, seems to separate the two pairs brighter pairs of stars. NGC 654 is a small fan shaped glow, at 40’ NNW of NGC 663. A bright mag 7.3 star marks its SE border. A true resolution of this dense cluster was not possible. The weak glow of NGC 659 can be seen with averted vision. This little cluster is located right next to 44 Cas and in the direction of NGC 663. It was my impression that I could see 4 faint stars embedded in a faint patch of light.
Site : Bekkevoort, Belgium ( 51° N )
Date : November 25, 2008
Time : around 21.30UT
Binoculars : TS Marine 15x70
FOV: 4.4°
Filter : none
Mount : Trico Machine Sky Window
Seeing : 2/5
Transp. : 3/5
Sky brightness : 19.64 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.)
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Rony
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rodelaet
Post Laureate
Reged: 04/28/06
Posts: 3063
Loc: 50°56' N - 4°58' E (Belgium)
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Here is the labelled sketch.
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Rony
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GlennLeDrew
Pooh-Bah
Reged: 06/18/08
Posts: 1283
Loc: Ottawa, Ontario, Canada
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Bravo! Especially for bringing to our attention one of the more distant OB associations observable. (Not enough observers have been made aware of these fascinating, large-ish substructures of our Galaxy. Perhaps because they generally are too large to squeeze into the typical *telescope's* small field of view!)
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frank5817
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Reged: 06/13/06
Posts: 4089
Loc: Illinois
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Rony,
Excellent sketch. We all need to be reminded from time to time about these stellar associations of the milky way. When I look at these open clusters I do not immediate think in terms of associations but rather individual open star clusters. Your great work continues. I really, really enjoy these binocular sketches and your attached narratives. Rony, I don't think you realize how good these binocular sketches are. The time and effort you put in is much appreciated. Beyond  .
Frank 
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CarlosEH
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Reged: 01/19/05
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Loc: Pembroke Pines, Broward County...
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Rony,
An excellent observation of an interesting association in Cassiopeia. The description and labels are much appreciated. Thank you for sharing it with us all.
Carlos
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cildarith
Carpal Tunnel
Reged: 08/26/04
Posts: 2357
Loc: San Diego, CA
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Nice work Rony! 
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Eric
6" f/6 Parks Newtonian
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rolandlinda3
Carpal Tunnel
Reged: 01/24/06
Posts: 2233
Loc: Crozet VA 22932
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Rony...I have a request. When you do one of these star fields one time, can I see some stepped sketches to see how you choose your anchor stars then proceed to fill in the rest? Your star fields are just plain outstanding while I am virtually intimidated by this large field. This one is pretty complex and you are so good at it. I think if I see your drawing in steps and sort-of see how you proceed, it might seem a little less frightening to try. In any case, I sure like your sketch. And...how long did it take you to do this? Roland
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Roland
Sketches in members galleries: rolandlinda3
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rodelaet
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Reged: 04/28/06
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Thanks for the replies, guys!
Roland,
The idea goes like this: I always have the digital sketch in mind while doing the field sketch. When I draw a star, I estimate its diameter for the digital sketch. I note this number next to the star. These are the labels on the field sketch. The brighter stars are drawn with a fine pigment liner. The faintest stars are always drawn with a pencil and thus bear no number.
Before I start, I just observe the field of view to get familiar with the star patterns. Then I choose a ‘central’ star. This does not need to be a bright star. It will become the reference star to come back to. The edge of the field of view is my second reference. Once I find my way around, I start to rate the brightness of the brighter stars. I draw these stars in relation to the central star. Once these stars are drawn, I number them. This process allows me to ‘recognize’ the most important stars and their patterns in my mind. Then I divide the field in smaller sectors. For the ease of sketching, I pan the binoculars around the field to get the desired sector in the center of view. I first concentrate on my direct vision and draw and label these stars with a fine pigment liner. When these stars are drawn, I switch to averted vision and draw the faintest stars with the pencil. I only use the pencil for the faintest stars, and omit the need to label these stars as well. Then I come back to the central star before choosing another sector. This process of concentrating on smaller fields makes the task much easier. The whole process can take an hour for a single sketch, depending on the number of stars visible.
When I make the digital sketch, I draw the stars in the same order as when I did the field sketch. And I use the same star patterns to find my way around, again.
I included the raw field sketch below. I hope that the pencil dots are visible as well.
Clear skies,
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Rony
My Astronomical Sketches
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frank5817
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Reged: 06/13/06
Posts: 4089
Loc: Illinois
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Rony,
Very nice. You have some nice time saving short cuts in here and an oustanding plan of attack on your sketches.
Frank
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Special Ed
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Reged: 05/18/03
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Loc: Greenbrier Co., WV 38N, 80W
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Rony,
An excellent sketch and skillful observation--thanks for sharing some of your technique.
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Michael Rosolina
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CarlosEH
Post Laureate
Reged: 01/19/05
Posts: 4142
Loc: Pembroke Pines, Broward County...
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Rony,
Thank you for the description on how you produce your outstanding deep sky observations. Your technique is very logical and the results speak for themselves. I look forward to your future observations.
Carlos
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keef
member
Reged: 12/27/06
Posts: 48
Loc: Derby, Derbyshire, UK
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Another great sketch - I found it interesting that you have shown us your RAW field work too!
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Celestron 114EQ
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My Site: http://www.derbyskywatcher.co.uk
Location: Derby, UK - Lat: 52.91N Lon: 1.47W
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rodelaet
Post Laureate
Reged: 04/28/06
Posts: 3063
Loc: 50°56' N - 4°58' E (Belgium)
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Thanks, guys.
Keith,
I'm working on a little article about 'simple' observing and (digital) sketching techniques. I need to translate it to English. I hope to finish it in a few weeks. It might give you some ideas to work with.
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Rony
My Astronomical Sketches
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rolandlinda3
Carpal Tunnel
Reged: 01/24/06
Posts: 2233
Loc: Crozet VA 22932
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Thanks Rony for the explanation. I am going over it a couple times then will try it. Roland
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Roland
Sketches in members galleries: rolandlinda3
Inspirational stories/sketches at:
www.christworksministries.org
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