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IC 5217 the "little Saturn" planetary nebula in Lacerta at 900x

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#1 iainp

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Posted 16 August 2018 - 07:35 AM

Another tiny planetary nebula, though how tiny is a matter of debate. Some sources say 6", others 12" and one reports it as 15". It seemed very small to me, and it took 900 magnification to see its elongation and the difference between the brighter core and the fainter shell.

 

I suspect the main core is 6" and the shell extends out to 12" or 15".  At 11.3 magnitude it's relatively bright for such a small object, and its surface brightness meant it was still pale blue at 900x.

 

In astro images it looks like a miniature Saturn, some say. It would be a stretch to say my sketch looks like Saturn but I'm happy to have captured its main structure.

 

Original sketch below. The = sign is recording the similarity in apparent magnitude between the PN and nearby star, even though that star is listed as 10.2 mag, so either the PN is even brighter than listed or I'm not so good as making these comparisons, though I'd be surprised if I couldn't spot the difference between 2 objects a whole magnitude apart!

Iain  

 

Attached Thumbnails

  • IC 5217 final w.jpg
  • IC 5117.jpg


#2 azure1961p

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Posted 16 August 2018 - 09:12 AM

A fine piece Iain!

 

It's sad that the more esoteric and tiny the more difficult it is to find decent links on the internet.  As I'm sure you've noticed, you end up with miss named objects that aren't what you were looking for at all and all the same very low res amateur ccd images. With persistence and cross referencing I think I looked up your objects image successfully. (I think!).

 

I think the discordant sizes are visual versus imaging versus telescope used, even what wavelength sometimes eh?   I'm betting you suggest the big sizes are the outter shell and the smaller being the inner brighter core.  

 

 

I think it's great you resolved an end to a point. Steve Gotleib mentions this being elliptical at 400x with an 8" but your 20 managed the resolution of the point and that's an interesting find.  In another forum a guy with a 24" mentions a point on the other end of the ellipse as well.  I think it's wild on such a small target you got what you did with the scope youve got.  Something interesting to consider is the SIZE of the pointed feature you resolved.  The 8 as reported by S.G. sees no pints but you have and if you follow along this route it speaks to the deepsky resolving power of your instrument here.  The point itself seperate from the ellipse looks roughly 2"x1", maybe more like 2"× 0.5"?  Scaling that up (or down) to my 8 that leaves me with a potential deepsky res of 5"x 1.25" or 5" x 2.5".  That actually sounds on the money at least for my scope where a stellaring or brightening in some planetary nebula and galaxies appear as about that minute size.  Just not quite stellar but approaching it.  Geez Iain... is this our deepsky Rayleigh Criteria ??!!  An interesting thing to bring to bare when perusing photos of potential objects to inspect.

 

Thanks for the post in bringing this to attention. It looks like a beautiful object and I'm envious of the light blue you detected.  I love my 8 but I'm forever envious of the color big aperture pulls in.

 

Pete



#3 niteskystargazer

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Posted 16 August 2018 - 10:01 AM

Iain,

 

Nice sketch of  IC 5217 (The "little Saturn" planetary nebula in Lacerta at 900x) smile.gif .

 

CS,KLU,

 

thanx.gif ,

 

Tom



#4 Jef De Wit

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Posted 17 August 2018 - 02:53 AM

Again a fine PN-sketch! I was not sure I could see his elliptical form at x343 with a 30 cm Dobson.



#5 iainp

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Posted 17 August 2018 - 03:49 AM

Thank you Jef, Tom and Pete. Pete and thank you again for your detailed response! Always leaves me with plenty to think about. You are so right about the difficulty of finding images of the esoteric and tiny PNs.  Where images exist they tend to be single blobs of overexposed white light.  I found Vy 1-1 last night and have spent half an hour this morning unsuccessfully trying to confirm or at least corroborate aspects of my observation. No matter, that's part of the joy of trying to tease out the detail of these very small PNs in a way imaging can't do. 

Iain 



#6 azure1961p

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Posted 17 August 2018 - 08:20 AM

You are at the visual frontiers of planetary nebula observation and the cross referencing of others finds becomes more scarce as a result. As it should be eh?

 

Pete



#7 hokkaido53

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Posted 29 October 2018 - 08:10 AM

Nice work, as always, Iain.

For purposes of discussion, I've posted my own recent drawing of IC 5217 below.

The planetary was hard to find, due to the rich Milky Way field in which it resides. At low powers, it looked like another star, so it wasn't until I used 343x magnification, did it appear nebulous - although not rectangular, as some of the photos show.

It was also difficult to find information on the Web about IC 5217. Some observers claimed it was in Aquarius! 

The Astro League's planetary nebula guide does have a photo of the nebula and its vicinity, but it doesn't look much like the other photos I've seen.

I finally looked at Alvin Huey's guide, and the photo there did look like the star field I had drawn, so I'm sticking with that.

Clear skies,

Roy in New Mexico

 

Attached Thumbnails

  • IC_5217_test.jpg


#8 frank5817

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Posted 30 October 2018 - 12:53 AM

Iain,

 

Very nice and the blue color captured. wonderful.

Roy, you too fine sketch of the same tiny planetary I have never seen.

 

Frank :)



#9 iainp

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Posted 30 October 2018 - 01:29 AM

Thanks Frank. Nice one Roy, these tiny ones can take a lot of tracking down! Sometimes I get them in 5 minutes, usually it takes me at least  15 minutes, often half an hour. And on some very frustrating nights I give up after an hour....

Iain 



#10 Randolph Jay

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Posted 01 November 2018 - 12:17 PM

Great work!  I enjoy also seeing how you process your notes and sketch.  Well done!

Regards,

Randolph



#11 azure1961p

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Posted 03 November 2018 - 06:54 AM

Thanks Frank. Nice one Roy, these tiny ones can take a lot of tracking down! Sometimes I get them in 5 minutes, usually it takes me at least  15 minutes, often half an hour. And on some very frustrating nights I give up after an hour....

Iain 

 

The highest I've tracked my dob at is 800x. It's WORTH it when say, I'm trying to see elongation in a profoundly tight elongated double but man o' man what a tedious way to go!!!!  It worked though.

 

Pete




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