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A handful of Arps and an Abell PN

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#1 Jeff Young

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Posted 13 October 2009 - 01:19 PM

There's not much in the way of eye-candy, but my most recent observing report does include sketches of several Arp peculiar galaxies and an Abell planetary.

Observing Report Thread

Cheers,
-- Jeff.

#2 frank5817

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Posted 13 October 2009 - 08:22 PM

Hi Jeff,

The first one in your list (NGC 6946/Arp 29) I have looked for in Cygnus but without success from my poor site.
The others I have never tried for I'm sure. These sketches are superb like all your very realistic eyepiece sketches of the deep,deep sky. You make sketching these faint targets look like they would be easy to do. But it gets more difficult in many ways as the targets get fainter.
Excellent work.
:bow: :rainbow: :bow:
Frank :)

#3 JayinUT

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Posted 13 October 2009 - 09:28 PM

Jeff,

Very close to my own observation of NGC 6946 and more realistic then my copy of the STSci image I copied.

Your techniques are wonderful and provide a great view of each object. I really like your two posts on Arp 113 where you show what you missed or mislabeled. I think I may do something similar to work on ensuring I get my star locations down in the right location relative to each other. Excellent as always, and I enjoy your comments as well.

#4 Jeff Young

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Posted 14 October 2009 - 03:37 AM

Thanks, guys!

I think NGC6946/Arp29 would be absolutely stunning under darker skies or with a big dob. While I see an "S" shaped spiral (and even that is somewhat difficult), I'm only getting the brighter two arms: the DSS images show a full face-on circular disk with at least 5 arms.

Cheers,
-- Jeff.

#5 CarlosEH

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Posted 15 October 2009 - 02:58 PM

Jeff,

An impressive collection of observations of interesting galaxies. Arp 29 does appear that it would look great in a large Dobsonian. Thank you for sharing them with us all.

Carlos

#6 Shannon s

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Posted 15 October 2009 - 03:20 PM

Great sketches Jeff. You have an impressive arsenal of instruments.

#7 JayKSC

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Posted 15 October 2009 - 04:52 PM

What a great collection of sketches of difficult targets! Thank you for sharing them and your detailed report. I especially like your drawing of Abell 81, in part as these elusive planetaries have always fascinated me (though I've not seen many myself, yet!).

- Jay
South Florida

#8 cildarith

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Posted 15 October 2009 - 10:36 PM

Jeff, your sketches and observation reports are always a treat. Thanks for sharing your sketches of these challenging objects. :cool:

#9 Jeff Young

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Posted 16 October 2009 - 08:53 AM

Thanks for the comments, everyone!

Here's another Abell for Jay from a couple of years ago:

Abell79 PK102-02.1 11/11/2007 22:46 UT; Pickering 5, NELM 5.5, SQM 20.7
406mm SCT @ 170x, OIII

First attempt was at 22:46, when transparency was poor (NELM 5; SQM 20.4). PN was *extremely* difficult at 175x with OIII -- holdable about 50% of the time but only for seconds at a time in averted and sometimes difficult to reacquire -- and completely invisible without filtration and at other magnifications.

I went back at about 23:45 when transparency had improved (NELM 5.5, SQM 20.7), and the PN was a bit easier -- holdable perhaps 75% of the time, and easier to reacquire. No shape, orientation or structure could be discerned.

Posted Image


Cheers,
-- Jeff.

#10 JayKSC

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Posted 16 October 2009 - 09:03 AM

Thanks for sharing this second Abell, Jeff! Another fine job sketching this difficult target - I have to almost use averted vision to see it in the sketch.

If it were so challenging an object in a 16-inch scope, I can't imagine seeing it with my biggest scope - a "puny" 6-inch refractor.

:) Jay
South Florida

#11 JakeSaloranta

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Posted 17 October 2009 - 04:02 AM

If it were so challenging an object in a 16-inch scope, I can't imagine seeing it with my biggest scope - a "puny" 6-inch refractor.


Abell 79 is visible at least in an 8" telescope with O-III filter. 6" telescope is not that far off and under dark skies I'm sure one could pull it off.

/Jake

#12 markseibold

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Posted 17 October 2009 - 05:06 AM

Jeff

Great sketch work and documentation. :bow: :bow: :bow:

Although you indicate use of a 16" mirror, you have tempted me to try to locate these deep sky objects for the first time with my 20 year old 10.1" Dobsonian as I am now temporarily under ultra dark skies again in the Cascade Mountain foothills 40 miles east of Portland.

Thanks for posting,

Mark

#13 Jeff Young

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Posted 17 October 2009 - 12:16 PM

Thanks for the comments, guys.

For what it's worth, my Irish skies aren't great: I've a decent amount of light pollution and the high humidity induces more scatter. In fact, my 10" Mewlon under pristine Colorado skies is nearly a match for the 16" in Ireland. So Jay and Mark, definitely give it a go, especially if you have dark skies.

I'm also of intermediate experience. While I can see far more than when I first started, I still can't see nearly as deep as Eric or Jake.

Cheers,
-- Jeff.

#14 JakeSaloranta

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Posted 18 October 2009 - 06:09 AM

Jeff,

I'm curious, how do you measure your limiting magnitude? I see you use SQM. Your SQM readings indicate that the limiting magnitude should be well above 5.5 (versus the SQM 20.7). Did you measure from the same spot with the SQM and using naked eye or do you just estimate the limiting magnitude?

My personal best from my suburban site, with my SQM-L meter has been 20.37 with limiting magnitude of ~6.0. With a SQM reading of 20.7 the naked eye limiting magnitude should be closer to 6.5.

Good sketches in any case. I like them a lot and especially the fact they're "hand made" - without Photoshop etc.
/Jake

#15 Jeff Young

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Posted 18 October 2009 - 02:03 PM

Jake --

I'm not very rigorous about NELM: I always use Ursa Minor, so it's really a limiting magnitude at 54° rather than at the zenith. I also have the older SQM unit which isn't directional, so the SQM reading is pretty much whole-sky.

Humidity also seems to play a large role: I've had NELM 6 nights where the SQM read as low as 20.5, and NELM 5.5 nights where it read as high as 20.8. But usually 20.8 and up gives me NELM 6, 20.6 and below NELM 5.5, and 20.7 is pretty evenly split between the two.

Cheers,
-- Jeff.






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