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NGC 4631 in CVn, with a 4 inch refractor.

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#1 rodelaet



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Posted 11 May 2009 - 03:28 PM

NGC 4631 is a challenging edge-on galaxy for small telescopes under light polluted skies. But the nicknames Herring Nebula and Whale Galaxy do trigger our imagination, as does the label Arp 281. Its visual magnitude of 9.2 together with its surface brightness of 13.3 explain the object’s pale appearance. The galaxy can be found halfway on the path from Gamma Comae Berenices to Alpha Canum Venaticorum. Look for a ghostly streak of light, like a smoke trail of a passing meteor. The galaxy’s core looks a tad brighter and elongated in an E-W direction as well. The boundaries of this amazing edge-on galaxy are difficult to determine. A mag. 12 star can be seen near the northern edge of the galaxy’s halo. NGC 4631’s distance is estimated at 23 million l-y.

Site : Bekkevoort, Belgium ( 51° N )
Date : April 19, 2009
Time : around 22.00 UT
Scope : Skywatcher 102/500mm achromatic refractor
Eyepiece : Baader Hyperion Zoom at 8mm
Magnification : 63x
FOV: 65’
Filter : none
Seeing : 3/5
Transp. : 4/5
Sky brightness : 19.87 magnitudes per square arc second near zenith (SQM reading).
Nelm: 5.4
Sketch Orientation: N up, W right.
Digital sketch made with Corel Paint Shop Pro X2, based on a raw pencil sketch.

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#2 kraterkid


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Posted 11 May 2009 - 06:49 PM

Rony, simply beautiful! :bow: :rainbow: :bow: These sketches, while pushing the limit of a 4" aperature, really help folks to see what is possible with a modest instrument. I love the 12th mag star to the north of the core, very subtle.

#3 daniel_h



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Posted 11 May 2009 - 06:59 PM

very subtle sketch - i had to clean my glossy screen to see it clearly

#4 JayinUT


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Posted 11 May 2009 - 07:31 PM


Wonderful! The quality of the capture and the details are tremendous. I can tilt the lid of my MacBook Pro and see different details. Well done as always and I do look forward to your next sketch . . . mine also if the weather ever would cooperate.

#5 frank5817



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Posted 11 May 2009 - 08:09 PM


Excellent sketch. On a good night from my location I don't see it any better and I certainly could not draw it as well as you have here. :bow: :rainbow: :cool:

Frank :)

#6 rodelaet



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Posted 13 May 2009 - 03:38 PM

Rich, Daniel, Jay and Frank,

Thanks for the kind comments. :)

#7 CarlosEH


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Posted 14 May 2009 - 01:12 PM


An excellent observation of NGC 4631, the Herring or Whale Galaxy. This is a challenging object to detect and you have done an admirable job rendering it. Thank you for sharing it with us all. A Whale of an observation!


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