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The joy of Jonckheere 320, a poly-polar planetary nebula

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#1 iainp

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Posted 22 November 2015 - 11:56 AM

I can't say I enjoyed this observation, in fact it was a night of frustration and disappointment, but the joy came in the last 5 minutes of the night when I finally bagged my prize.

 

 I went to bed early because there seemed no chance for astronomy:  the moon was up, and icy winds were building which, as predicted, led to snow later. I was reading about a planetary nebula, Abell 12, which sits almost on top of the naked eye star Mu Orionis. I looked out the window and could see the star! 

 

This was obviously the Universe calling, so I headed the call. 10 minutes later I was dressed and at the eyepiece and searching for the PN (another joy: having the scope observation-ready in a shed:  just wheel it out and off you go) .  At 40 arcseconds across and 12.4 mag, I thought I'd be able to spot it, even with the Moon up, as it was on the opposite side of the sky, but it was a complete fail. I gave up after about 40 minutes of trying every magnification, eyepiece and filter.Nothing.

 

 Since I'd come this far,  I thought I'd try Jonckheere 320 (also known as J320 or PN G190. 3− 17.7) also in Orion.  It's a planetary nebula with an unusual and complex structure,  a "poly‐polar planetary nebula surrounded by point‐symmetric knots".  I'd read about it earlier in the day but hadn't planned to observe it any time soon, and had no idea what it looked like. 

 

Harrington's book Cosmic Challenge lists it as 12.9 magnitude and a tough one for scope of 6" -9.25" aperture, but it's possible, he says,  with an 8" scope even with suburban light pollution. The problem is its size: 26 X 14 arc seconds.  It was actually mis-catalogued as a double star by Robert Jonckeere until he revisited it in 1916 using the 28 inch refractor at the Royal Greenwich Observatory.

 

Long story short: I couldn't find it. With the light pollution and moon, I got mixed up as to which star to begin the star hop in Orion's bow. But I kept at it for an hour, and eventually honed in on the star field. At that exact moment thick cloud rolled in. I waited inside for 15 minutes and it cleared a bit, I rushed out and clouds rolled in again. 

 

With almost 3 hours and nothing to show for it, I was wondering why I'd bothered, then there was a break in the clouds and I got it!  I managed the briefest of observation, and just managed a sketch before it was gone. 

 

Here's the result.  The OIII filter didn't seem to help much and the only way to glimpse any structure was at 546X. Yet it still was very tough to pick out anything even at that magnification.  It appeared as a disc to begin with, then there were hints of elongation, giving it an ovoid shape.  Just for a few seconds I saw what looked like a brighter knot at one end.  

 

Under the sketch is a comparison with the Hubble image.  I was pleasantly surprised to see the reasonable match, as my observation of the shape and the brighter knot was very tentative and fleeting, and the sketch was rushed in a minute or two.  I'm pleased I hadn't looked at any images of it before observing and finishing the sketch,  otherwise it would have been very easy to confuse what I was seeing with what I was expecting to see. 

Attached Thumbnails

  • J320b.jpg
  • j320 hubble.jpg

Edited by iainp, 22 November 2015 - 12:42 PM.

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#2 Randolph Jay

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Posted 22 November 2015 - 04:30 PM

Well you did it!!! What a cool comparison with the Hubble image. I must congratulate you also on your doughty persistence. I've reached the point where I can't "play chicken" with clouds....they will usually win and I'll be back in bed. Great job!
Regards,
Randolph

#3 mike73

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Posted 22 November 2015 - 04:51 PM

A tricky night but worth it in the end eh Iain? I haven't had a chance with the weather down these parts and work commitments getting in the way but I now have two weeks off so fingers crossed!

 

I'd never even heard of Jonckheere 320 until I saw this, a small object but you caught a lot of detail, another excellent observation!



#4 iainp

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Posted 22 November 2015 - 05:15 PM

Thanks both.

 

 Yes, Randolph, I normally don't like to take the weather on these days either. When I bought the 16" 8 years ago, I used to valiantly drive up the A1 for an hour to find dark skies, and very often found I'd got cloudy skies instead.  There's only so much you can take of that sort of thing, hence after a short while the scope ended up rotting in the garage and greenhouse for all those years.

 

 Mike I know how you feel, even after repairing the scope last year,  it didn't get used for the whole year, as the 1.5 or 2 hour commute to work and the same home left me with no energy or desire to stand in a freezing garden all night. Now I'm free, (voluntary redundancy)  I have all the time in the world, and best of all, I can match my sleeping to the heavens.   At 5.00 this morning Coma Benenices was already getting quite high in the sky, and  I pointed the scope in the general area and saw 10 galaxies in a slow sweep.  I'd been out since 2.00 am so unfortunately I was too cold to do anything useful by this time,  but that's the kind of thing you can only do when you don't have a job to go to. It's marvellous! (apart from the small matter of having no money left of course  :) ) Enjoy the break, and fingers crossed for some clear skies, maybe even dark skies. It's got to happen one day hasn't it?? 


Edited by iainp, 22 November 2015 - 05:17 PM.

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#5 Asbytec

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Posted 22 November 2015 - 07:15 PM

Iainp, I am retired with all the time in the world, too, except for my volunteer work.

 

What can I say about J320 except its a great observation made with perseverance. It paid off. The sketch is beautiful and appears to be spot on. You can sleep well. :)

 

Here's another image of it for comparison. 

http://www.pbase.com...image/150620355


Edited by Asbytec, 22 November 2015 - 07:15 PM.


#6 Sheliak_sp

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Posted 23 November 2015 - 01:21 AM

Wow, I didnt know this object! Thats a nive sketch and report. Thanks for sharing, iainp, it seems so interesting! Clear skies!

 

Migue



#7 iainp

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Posted 23 November 2015 - 08:16 AM

Thanks Migue. And you too Norme. I saw that image -  it's the only one I could find apart from the Hubble one - and used it to confirm that I'd got the orientation for the elongation right, then couldn't find the site again, so thanks for the link.

 

  I feel like I'm retired too. The "full time" PhD in Philosophy I'm doing is far from full time, at least at the moment, though I'm only a couple of months into it.  People said I'd feel lost, being away from work, but that's not been the case at all, quite the opposite.  I'm going off topic here, but here's a Before and After redundancy pic of me on my blog  :)

 

http://fouragesofsan...redundancy.html


Edited by iainp, 23 November 2015 - 08:17 AM.

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#8 Asbytec

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Posted 23 November 2015 - 09:02 AM

The after picture is much better. :)



#9 iainp

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Posted 23 November 2015 - 09:16 AM

I'd have to agree. The first picture graphically illustrated what teaching in a Further Education College for a decade does to people  :)



#10 starquake

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Posted 23 November 2015 - 09:42 AM

All right, I must get Phil Harrington's book. :) I wonder how many "unlisted" but visible objects lurk around that are omitted from the NGC/IC heavy maps.



#11 iainp

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Posted 23 November 2015 - 10:06 AM

Definitely worth it, I'd say. He's very good on 'dissecting' familiar objects too, eg. finding faint galaxies near M13 and emission nebula in M33 and M101.  Here's a link to it on Google Books, which shows many (most?)  of the pages in case you want to look before you buy, as it's not cheap. I got it second hand on Amazon. 



#12 starquake

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Posted 23 November 2015 - 11:40 AM

Thanks for the link. Yep, I prefer the real paper, but I'll try to find a second hand too, because this year's Christmas wishlist  of books is already en-route to me. ;)  (If interested, here's a list of my astronomy related collection: http://magictron.com/ba/books.cgi )



#13 frank5817

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Posted 23 November 2015 - 11:48 AM

iainp,

 

This is a very fine sketch of a planetary nebula I have never observed.

You are very patient and  persistent observer which will always serve you well.

 

Frank :)


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#14 starquake

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Posted 23 November 2015 - 11:54 AM

Hm, an interesting off-topic thing from the book: Phil writes, that the limiting magnitude for a 12" scope is about 14.5m, but experienced observers may better this by .5 mag or more. The I hereby qualify myself as very experienced :D , because my records are 15.8m DV and possibly more, because I regularly see stars that are not listed by my sky map software. Perhaps I should check POSS data.



#15 iainp

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Posted 23 November 2015 - 12:04 PM

Thank you Frank,  it's the CN forum which has given me discipline  :)  Actually, I'm only half-joking. On more than one occasion recently I've thought "I can't give up now; I'll have nothing to show the Guys and Girls tomorrow."  It happened 2 nights ago when I was shaking with cold, lost all feeling in my feet and the scope was literally covered in a fine sheen of ice. I powered through to sketch M101, coming soon. 

 

Ferenc you've stunned me, not only with the collection, but with its organisation too!

 

I'm still finding out what my scope can do (with me attached to it I mean) . The best I've managed  so far in 'confirmed' observations is a 13.3 mag planetary, but I must be able to do better than that. 


Edited by iainp, 23 November 2015 - 12:07 PM.


#16 starquake

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Posted 23 November 2015 - 12:12 PM

My 15.8m record is of course an individual star. I'm quite in trouble with brightness estimates of large surface objects. I think in a good evening you should well go above 16-16.5m with your setup. How much is your regular naked eye limiting magnitude?



#17 iainp

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Posted 23 November 2015 - 12:23 PM

I'm just starting to try to estimate NELM, something I'd never done until I joined CN. I've got 3 parts to my sky: urban light dome to the south, (nearest town),  mild light pollution to the west and north (the village) and quite good dark skies to the east and south east (I'm right on the edge of a nature reserve) so there's a lot of variety, let's say. But on a good night the milky way and dark band within it are clearly visible. On those good night I can see mag 5 stars without really trying hard, so presumably I can go better than that.  I'll let you know on more accurate NELM and also on what I see through the scope. 



#18 niteskystargazer

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Posted 23 November 2015 - 02:04 PM

Iain,

 

Nice capture of Jonckheere 320 :) ,

 

CS,KLU,

 

:thanx: ,

 

Tom



#19 Special Ed

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Posted 23 November 2015 - 03:26 PM

Hi Iain,

 

I enjoyed reading your report--we've all been there searching hard for some elusive object and sometimes coming up with nothing.  Glad your story had a happy ending--nice sketch.  :)

 

BTW, don't know what you mean by "voluntary redundancy"--must be a UK thing.  I have heard of the Department of Redundancy Department.  ;)



#20 iainp

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Posted 23 November 2015 - 03:42 PM

Thanks Ed, I thought my pain might resonate   :) .  In the UK,  management are very keen on voluntary redundancy (well certainly in Further Education colleges).  They want to cut jobs, and offer people at risk of losing their jobs an 'enhanced package' to go. The clever part is, if they don't take it, the teacher risks losing their job anyway, and having to leave with only the statutory minimum so most people jump before they are pushed.  Legally, it's easier to lose people if they've chosen to go, so it's an advantage for the college to press for it.  I actually got 'bumped' which is even more complicated.   Bumping is when you are not even at risk, but so desperate to go that you offer to take someone else's voluntary redundancy and they get to have your job. I love bumping  :cool:



#21 Asbytec

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Posted 24 November 2015 - 05:39 AM

I have heard of the Department of Redundancy Department.  ;)

 

 

I used to work there. And we used to call ourselves government workers, which is an oxymoron. 



#22 taxibill

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Posted 27 January 2019 - 02:14 PM

Congrats on your mention and link in this months Cosmic Challenge!



#23 iainp

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Posted 28 January 2019 - 01:46 AM

Hi Bill, thank you for the heads up about the Cosmic Challenge! I knew I'd be famous one day :-) I've been neglecting astronomy  for months now (it's those freezing winter UK nights, they really separate the men from the boys. I'm a boy) but coming back here reminds me what I'm missing out on so will hopefully be dragging the scope out soon. Regards, Iain 




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