rodelaet
Post Laureate
Reged: 04/28/06
Posts: 3063
Loc: 50°56' N - 4°58' E (Belgium)
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NGC 7789 is often called the most beautiful open cluster of Cassiopeia. But does it really deserve that title? From a binocular observer’s point of view, I would propose a few other fine candidates as well. That said, NGC 7789 sure is a fine collection of minute stars, wrapped in a large uniform glow. Binoculars have a hard time resolving individual stars in this comet-like object. All of its stars are fainter than 10th magnitude. From my light-polluted backyard, the cluster appeared half as large as the full moon. It struck me that the western edge of the cluster was sharply bordered, compared to the ever fading eastern edge of the cluster. From time to time, a minute star popped into view. I was able to resolve about 8 stars that way.
NGC 7789 has a true size of 44 l-y and is 6000 l-y away. Its age is estimated at 1.6 billion years.
NGC 7789 is easy to find, as it is only 3° SE of Beta Cas. To make things even easier, Rho and Sigma Cassiopeia serve as additional signposts N and S of NGC 7789. Both are fine double stars. While anchoring the field sketch, it seemed to me that Rho’s primary showed a nice orange hue, while its companion displayed a white blue tint.
Site : Bekkevoort, Belgium ( 51° N )
Date : October 22, 2008
Time : around 21.00UT
Binoculars : TS Marine 15x70
FOV: 4.4°
Filter : none
Mount : Trico Machine Sky Window
Seeing : 3/5
Transp. : 3/5
Sky brightness : 19.66 magnitudes per square arc second near zenith (SQM reading).
Nelm: 5.35
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
My Astronomical Sketches
My Binocular Sketches
Callibrate your Monitor with this little strip.
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GlennLeDrew
Pooh-Bah
Reged: 06/18/08
Posts: 1269
Loc: Ottawa, Ontario, Canada
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Lovely, as usual!
About rho Cas, an interesting object itself. It lies *at least* as distant as NGC7789, and most likely farther; one current estimate puts it at ~8,000 l-y, within the Cas OB5 association. Were it not for interstellar extinction, it would be about 2 magnitudes brighter than its actually-observed 4.5m. It's a yellow hypergiant, and at a luminosity of some 1/2 million Solar, it's just about as luminous as a star can be. Compare its apparent brightness to that of the brightest red giants within 7789, which themselves are about 1,000 times the Sun's luminosity.
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Home-made 11X50 right angle bino, 8.1 deg. FOV
Modified 26X100 bino, 3.5 deg. FOV
Home-made Mk II RA bino, using interchangeable objectives and eyepieces
My Gallery
Mediocre minds discuss people. Good minds discuss events. Great minds discuss ideas.
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frank5817
Post Laureate
Reged: 06/13/06
Posts: 4084
Loc: Illinois
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Rony,
Excellent sketch. Your wide field with the binoculars is terrific.   I can't pick this one out with binoculars from my location but the telescopes can get it.
Frank 
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my gallery
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rolandlinda3
Carpal Tunnel
Reged: 01/24/06
Posts: 2233
Loc: Crozet VA 22932
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As usual, very nice, Rony.
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Roland
Sketches in members galleries: rolandlinda3
Inspirational stories/sketches at:
www.christworksministries.org
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CarlosEH
Post Laureate
Reged: 01/19/05
Posts: 4138
Loc: Pembroke Pines, Broward County...
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Rony,
A very attractive open cluster in Cassiopeia. NGC 7789 does appear to glow in your excellent observation. I will have to examine it myself soon. Thank you for sharing it with us all.
Links;
http://www.hawastsoc.org/deepsky/maps/cas/cas2.gif
http://messier.obspm.fr/xtra/ngc/n7789.html
http://apod.nasa.gov/apod/ap990709.html
http://www.starrywonders.com/ngc7789.html
Carlos
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keef
member
Reged: 12/27/06
Posts: 48
Loc: Derby, Derbyshire, UK
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nothing but the best from Rony!!
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Celestron 114EQ
CG-3
Pentax Optio M20 (P&S)
Canon 400D
Bressar 10x50
Revelation 15x70 (w/ Heavy duty 'L' adapter)
NexImage Solar System Imager
The GIMP (Image processing software)
Stellarium
My Site: http://www.derbyskywatcher.co.uk
Location: Derby, UK - Lat: 52.91N Lon: 1.47W
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Demelza
super member
Reged: 05/07/06
Posts: 184
Loc: The Netherlands
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Another nice sketch, Rony! I really love you're technic!
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Take a look at my website: Observing the night sky.
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jdavalos
member
Reged: 08/24/04
Posts: 69
Loc: Guadalajara, Méx 20.30N\103.20...
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Excelent... as ever!
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Mark9473
Post Laureate
Reged: 07/21/05
Posts: 3211
Loc: 51°N 4°E
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It is a superb sketch as ever. On the other hand it's the first in Rony's series that *to me* doesn't fully do justice to this object. But I'm sure that's only because in my 20x80s it's larger and better resolved than in Rony's 15x70. It still is a fantastic sketch!
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Mark
Leica 8x20; Vixen 8x42; Swift 8.5x44, 10x50 and 20x80; TS 7x50; Orion 15x63; Docter 15x60
WO Megrez II 80 FD + Baader 90° T2 Amici
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NerfMonkey
sage
Reged: 06/12/08
Posts: 482
Loc: NE Ohio
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The more I see your sketches the more it makes me want to get out and do a few myself.
This cluster looks amazing. Reminds me of a weak glob with some bright stars on it, like M71 as seen in a telescope. Wonderful sketch.
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Mike
Zhumell 12", Oberwerk 15x70s
107 Messiers, 247 total DSOs, 6 planets, 1 comet
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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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Thank you all for the positive comments!
Glenn, your remark about Rho Cas is most interesting. Thank you!
Carlos, thank you for the fine links.
Mike, I can only recommend to sketch once in a while when observing. The act of sketching will force you to observe more intensely and to see more details. The sketch will be a nice souvenir.
Mark9473, I'm glad that you share your experience in comparison with my observation. Chances are that you perceive the object in a different way. Several reasons come to my mind. First of all, the observation is a very personal experience, and my eyes may differ from yours. We do use different instruments as well. A cluster on the virge of resolution in my bino's can show many members in your pair. Another important factor can be the sky quality. These last observations of mine are done in my backyard, where I loose a full magnitude compared to my other observing sites. I have no idea how dark your typical skies are? All this is to say that I find your experience very valuable. Thank your for sharing, really! 
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Rony
My Astronomical Sketches
My Binocular Sketches
Callibrate your Monitor with this little strip.
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Special Ed
Post Laureate
Reged: 05/18/03
Posts: 4297
Loc: Greenbrier Co., WV 38N, 80W
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Rony,
Excellent observation and drawing--you have a really fine technique and presentation style, but the details wouldn't be there without your observing skills.
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Michael Rosolina
8" f/10 Orange Tube SCT
4.25" f/4.2 Astroscan Reflector
SVP 3.6" f/13.6 CA Reflector
40mm PST f/10
APM Germany HD 15x70 binoculars
Canon 12x36 IS II binoculars
Mark I Eyeball
My CN Gallery
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winterspace
newbie
Reged: 10/15/07
Posts: 1
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Insuperable.....magnifico 
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Kris.
Pooh-Bah
Reged: 09/16/04
Posts: 1276
Loc: Belgium
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Excellent drawing Rony, you're sharpening your skills with every new sketch you make! i just hope you don't run out of targets
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Kris
To be old & wise, you first gotta be young & stupid
8" dob
AstroTech 66ED/APO
TAL 120 newt.
my CN sketch & picture gallery
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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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Michael, Winterspace and Kris,
Thank you!
Kris, fine targets are not my main issue, clouds are! 
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Rony
My Astronomical Sketches
My Binocular Sketches
Callibrate your Monitor with this little strip.
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markseibold
Pooh-Bah
Reged: 01/19/08
Posts: 1084
Loc: Portland Oregon
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Rony
Beautiful sketch-work! If I had seen it posted elsewhere or printed in a book, I would have thought it was a high resolution photograph! Very realistic! I am surprised that you had not entered it into the monthly contest.
The beautiful stark color contrast of the two orange and blue stars and the subtle nebulosity-like effect of the cluster reminds me of the endless nights I spent in my parents front yard as a young teenager, just scanning the skies along the Milkyway with my first binoculars.
Thanks for posting this,
Mark
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