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NGC 4618/Arp 23 & NGC 4625 in Canes Venatici

DSO Sketching Visual Observing Report
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#1 bphaneuf

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Posted 07 April 2024 - 08:19 PM

NGC 4618 / Arp 23 and NGC 4625 in Canes Venatici:

 

A final observation after finishing with Markarian’s Chain.  NGC 4618 is a single-armed, barred spiral galaxy.  The asymmetry of the arm being more prominent to the south of the bar is due to interaction with nearby NGC 4625, however recent studies have shown that may be only a partial explanation and that the lopsided arm structure may be due to internal forces of the galaxy itself.  NGC 4618 sits at a distance of approximately 20 million ly.

 

Observing:  The galaxy is bright and displays a prominent bar, from which the central core is barely discernible.  The long axis of the 1.5:1 oval is oriented NE-SW.  The halo is asymmetrical due to the single arm configuration and is not uniform in brightness.  North of the bar is a faint haziness, but immediately to the south-southwest is a dark area between the bar and the arm.  The dark lane does not extend to the east. That area is hazy all the way to the east end of the bar.  Also to the south-southwest the arm brightens significantly in an elongated tear-drop shape tapering to the east and thicker to the west.  The brightness does not extend to the west end of the bar, but the haziness of the arm does. The outer edges of the arm are faint and extend nearly halfway to the bright marker star to the south. 

 

NGC 4625 is not quite as bright as its larger companion but stands out clearly next to a marker star to its southwest.  The galaxy is nearly circular and brightens toward the middle to prominent core.

 

Sketching: white pastel pencils and white pastel powder on Bachmore 92 lb. black multimedia paper.    4618’s bar was drawn with a #6 Filbert brush and the prominent part of the arm with a #2.  The general haziness of the halo was filled in with a light load of powder on the #6 Filbert.  The darker lane was created by using a #5 pointed brush to remove powder.  4625 was drawn with a #2 round brush and a 12/0 mini angular did the core.  Touching up used about 4-5 different brushes.  For some reason, 4618 was a bear.

 

NGC 4618 - Arp 23 in CVn.jpg

 

Thanks for looking!

-b


Edited by bphaneuf, 07 April 2024 - 10:21 PM.

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#2 AGrayson

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Posted 07 April 2024 - 09:57 PM

Great sketches, your ability to pick out these faint galaxies and details within them is inspiring! Not only that but how you apply them to a drawing is realistic and puts me right in the eyepiece.

Great work!
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#3 frank5817

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Posted 07 April 2024 - 10:12 PM

Butch,

 

That large wrap around arm shows very nicely in your sketch. Impressive work.

 

Frank :).


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#4 JMSchwartz

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Posted 08 April 2024 - 09:56 AM

B- Awesome Beautiful, sketch. I'm going to have to look at this one. 

Cheers  Jon 



#5 niteskystargazer

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Posted 08 April 2024 - 10:59 AM

Butch,

 

Nice sketch of NGC 4618/Arp 23 & NGC 4625 (In Canes Venatici) smile.gif .

 

CDS,KLU,

 

thanx.gif ,

 

Tom


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#6 Herodotus

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Posted 10 April 2024 - 09:09 AM

Very nice

#7 bphaneuf

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Posted 11 April 2024 - 11:10 AM

Thanks for the encouraging words Frank, Mike, Grayson, Jon and Tom and for the likes!



#8 Procyon Lotor

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Posted 14 April 2024 - 09:44 AM

I observed this pair for the first time last year and made a sketch. They are fascinating to observe. Nice work!



#9 Nankins

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Posted 01 May 2024 - 03:41 PM

So great.  Funny, I am posting on my first ever observation of these objects last night in the observation log forum, and searched for these two on the Internet.  Clicked a link thinking I would get more information about them, and it was a CN link!


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#10 astronz59

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Posted 03 May 2024 - 03:53 AM

Excellent sketch and beautiful capture of some exquisite details, Butch! bow.gif waytogo.gif


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#11 nof

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Posted 03 May 2024 - 07:41 AM

I think you have X-ray vision Butch to observe and sketch all those details in the darkness.

#12 bphaneuf

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Posted 03 May 2024 - 09:05 AM

Hey Neil.  I do have a red light on the clipboard.  So Marvel hasn't tried to recruit me.  I protect my observing eye with an eye-patch, but sometimes I need both.  However, with the light on its dimmest setting and angled such that it doesn't reflect back at me re-adapting only takes a few minutes. 




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