NGC 4088 - Arp 18

Hello everybody,

here a sketch of Arp 18 - by working with my 12".

Conditions quite good - NELM around fst7 and seeing was okay.
Pic with comparison to wikisky-screenshot.

Please tell me if inserted pic does not work.

Attachment 2481

CS
Norman

Very nice.

Very impressive sketch/detail with that aperture. Here are my last two observations of NGC 4088

48" (4/4/11): this is a showpiece spiral in the 48-inch with the startling eyepiece view matching the detail in the DSS image. The galaxy extended 5.5'x2.0' SW-NE. Near the center is an elongated, extremely bright core. The very bright central portion extends from the core in a roughly 2'x0.5' region towards the southwest but is concave a bit, bending slightly towards the south. This feature appears similar to a slightly distorted central bar. Just south of this central bar is a dust lane extending SW to NE that parallels the bar, though it is more contrasty to the northeast of the core.

The dust lane separates the bright bar feature from a very long arm that extends the entire length of the galaxy along the south side and vaguely emerges from the southwest end of the bar. This arm is clumpy with a couple of large, bright knots to the south of the core and another prominent knot towards the east end of the galaxy (1.7' NE of the core). Beyond this knot the arm quickly dims, fans out a bit and bends to the north towards a mag 13.5 star.

Emerging from the northeast end of the core is a second prominent arm that immediately doubles back towards the southwest on the north side. This arm nearly parallels the central bar to the north and is separated by a less contrasty darker strip or lane. This clumpy arm contains a fairly prominent knot only 0.6' NW of the core. After this point the arm dims dramatically continuing a bit further southwest. The two main arms, along with the central bar create a squashed irregular "Z" appearance. MCG +09-20-092 lies 5' SE in the field ("faint, small, round, 20" diameter, fairly low even surface brightness").

18" (3/13/10): using 280x this striking, irregular spiral extends 5:2 SW-NE, rougly 5'x2'. The surface is noticeably mottled and clumpy with a dark patch or dust lane that extends to the south of the core with a weaker darkening to the north of the core. At the northeast end of the galaxy, a portion of what appears to be a spiral arm emerges from the main body and bends to the north. The corresponding feature on the SW end of the galaxy, bending south, is much more subtle.

Hi Steve,

thank you very much for your kind reply. Nice observation and really thorough description!

Indeed this is a very nice object - the prominent dustlanes suprised me whereas i did not know where the dark structures come from to that time. The dark lanes in the sketch are far more prominent than in the eyepiece of course. I overemphasized a bit, following an general advice of an 27"owner ... (Hi Uwe ;-)) However, by averted vision the dark lanes appeared relatively easy but hard to fix in length. Very surpising and nice feature - the reason for my sketch. One of my favorite galaxies since that observation (didn´t know this object before).

Thank you too Ivan.

CS
Norman

Hi Norman,

I agree, your sketch is quite excellent - it portrays the two galaxies naturally, and the stars and the dark grey background are shown naturally too. It's also a reminder that a 12 inch scope can show quite a lot!

Howard

Hi Howard,

thank you very much too for your detailed honoration :-) I myself like dark grey as background the most indeed. A very dark grey or even black appears unnatural to me. And "Yep!" ... 12" is in my eyes a very good size for a scope. In my case at first because of transport issues - without havin´a car - and havin biggest possible aperture under that circumstances.

During past years i had several chances to look under best conditions through scopes around more or less 20", on rare occasions up to 36 and 42".
And often/ mostly i was quite satisfied with what 12" has shown in comparison to these sizes. Seeing is often an issue here in Germany, so that smaller scopes can compete with the 20"+ category in many situations. At least in my opinion. But this is a philosophy by itself ;-)

However i´ll try to present some more sketches now and then to emphasize what 12" can do ;-)

Thanks again!

CS
Norman

Nice work, also when the DSS beside is not required to verify your accurate sketch.

As you already mentioned I find it essential to overdraw some details to make it a stranger (and me in the future) possible to recognize the observed details. The disadvantage is of course the loose of the natural impression.

I had an old observation with 16" with the fainter companion in the SE.

16", 315x, NELM 6m5+, Seeing III
Attachment 2483

Hi Uwe,

thank you too. I show the DSS for several reasons - one of which is my own interest in the comparison and - above all in this case - the real appearance of the object itself. Proving accuracy is not my first interest here, but of course it plays a role too ;-)

Very interesting sketch Uwe - looks like a ghost with hoody :-)) For 16" which is not that far away from 12"... i´d say great detail! Maybe i should have been using more power... i´ll try next time.

CS!
Norman

Hi Norman,

That's a beautiful drawing!
In my opinion it's necessary to overemphasize some details as well. I wouldn't be able to draw a feature absolutely realistically that I spotted only after an hour of observing.

Hi Peter,
thank you!

CS
Norman

Hi All,
An other sketch of NGC 4088 from southern Alps, and a 25" scope:
Attachment 2740
More details at: http://www.deepsky-drawings.com/?sen...c+4088&x=0&y=0
Clear Skies
Bertrand
http://www.deepsky-drawings.com/