I had to think a little bit about how to reply to your post. Whilst I agree that my choices of NGC 5844 might be considered certainly not among the brightest of the planetaries, I do think it is probably one of the most interesting, and though it not as spectacular, it and NGC 4071 are likey the largest common-garden variety planetary objects in our "neck of the woods" (Well George W"UUA" Bush is in town)
For me, perhaps this is because of structure and observed size that is the draw card. As I stated before; "Magnitude is certainly the major factor, but personally I think that visible structure and colour ranks more important in suitability and attractiveness."
So my own reasoning is as follows;
1) NGC 5844
NGC 5844 is 12.2v / 13.2b planetary subtends roughly 53x40 arcsec, and one of the bright example of the bipolar planetary nebula, whose structure looked like the bulb part of wine glasses joined end to end. Planetaries are not really symmetrical bubbles in space, but are like open ended spheres with an slightly thin equatorial disk which are thinner at the poles. The huge energies liberated by the planetary nebula nucleus (PNN) - the precursor to final exposure of the hot white dwarf core - radiate out from the it and force the bubble to expand. Eventually it breaks the walls of the polar regions of the shell, and the once held back outflows from the PNN, producing long flares of material flowing out into the surrounding space - like on of those old volcano fireworks with the burst of spectacular sparkles.
Although in NGC 5844's case they look like "two crabs in the act of procreation" (Don't ask me how I know this, by crabs - the jimmy and sook (male and female) - don't actually mate, ahem, backside to backside.), we are look at the structure as it appears across its long-axis and looking straight down on its central equatorial axis, which on the image I've attached is the small axial width. (Interesting if we were looking straight down the longest axis, 90 degrees to what we see from Earth, what you would see in a ring-like structure - similar to the Ring Nebula M57.)
Observationally, as describe in the Neat Southern Planetary Series (See http://www.blackskies.org/nsp04.htm ), but in summary NGC 5844 can be observed as follows;
"As an ovoid shaped object it is just visible in 15cm, best found using an O-III filter with medium power. In AOST2 (Astronomical Objects for Southern Telescopes - E.J. Hartung), David Frew states that it can be easily found by blinking across the field in an O-III filter. This is true for 10cm or 15cm telescope, but any larger aperture can immediately detect its nebulosity. Using the O-III filter, the brightness is fairly even across the entire disk. I could also see a slight indentation in the northern edge of the planetary. Using 30cm, the appearance of this indent becomes more pronounced, revealing an uneven edge, and this turns into a "bay" in telescopes exceeding 40cm. Larger telescopes should also start to see some structure in the planetary - perhaps more obvious using an O-III or H-Beta filter. Observers at Bowen, including (now ASNSWI President) Les Sara, thought that the appearance seemed mottled - and even more so with the O-III. Some faint bipolar features were also noted, with some difficulty, by each of them."
NGC 4071
I added NGC 4071 to my "Honourable List" mainly because of its structure as well. Unlike NGC 5844, NGC 4071 hasn't yet broken out of it shell, and in an example of a low-excitation planetary nebula. (This means the energy given off by the pre-white dwarf PNN is lower than the average planetary, and therefore is not as bright nor as structurally complex. The beauty of NGC 4071 is the shape of the surface off the bubble is very obvious. [ See also the article on NGC 4071 : NSP 19 at;http://www.blackskies.org/nsp19.htm ]
This also explains my reaction to Steve Quirk's image of NGC 4071, which is probably the most structurally intriguing PNe of all.
So although I agree it is exclusively faint, what we are looking at is almost a perfect soap bubble whose polar axis is pointing in the direction roughly 65 degrees to the line-of-sight - hence my suggested common name the "Eyeball Nebula" - or as Foghorn Leghorn catch phrase would be saying "...and that's a joke son."
[See image at http://www.blackskies.org/images/nsp...%20Fig5nsp.jpg ]
As to Les' comment, "Remind me, is this the faintest PNe iof the 90-odd in the NGC?", no, but it is in the bottom 20% Although it is listed as 12.9p magnitude - its size of 63x 40 arcsec and has a very low surface brightness.
So in my opinion...
The problem with the "Best of..." or "Top 10" lists are that they are very highly subjective. It comes down to what is one man's caviar is another man's fish eggs.
So as Greg said in his original post;
"I'll eventually compile my own list based on a combination of my own
taste/experience and the comments of others... So, what are your top ten planetary nebulae and why"
I think I've done that...
AJames
(Now aka. the 'Phoenix now in the Night Air')
"You maybe right, I may be crazy,
Oh, but it just might be a lunatic you're looking for."
They are not top 10 PN but I saw NGC 5844 (mag 13.3, size 68") and NGC 6026 (mag 13.2, size 54") last night. The first is easier to see than the second because 6026 has a faint star in it. I don't have Argo Navis or goto so it took a while to find them.
Sorry Glenn. when you refer that; "They are not top 10 PN but I saw NGC 5844.." You were referring to Les' list NOT my list.
Anyway - for NGC 5844 - so you got a bit more detail than you needed...
My list is short because these are the only PN's I have observed as yet. As you can see below I use a 4.5" reflector, so am kind of restricted to the brighter variety. I still try for some of the fainter PN's and have had mixed results, some I find, and others are no where to be seen. So here's my list so far, and I have included a wish list that I haven't had a chance to track down yet.
All time Favourite is M57 the Ring Neb. Although smaller than some of the others it was the first I ever found and every time I go back and look at it, I can see more detail. excellent object.
M27 The Dumbell Neb, although I can see the dumbell shape, overall it doesn't seem as pleasing to the eye as M57.
Saturn Neb, once again generally not as pleasing.
Helix Neb, only found this one on the weekend, (thanks Rob_K), although its huge, and the ring effect is visible, in my scope it lacks further detail than that.
NGC 246, Very very faint, but could still see the round shape and a little star cluster. (which I presume is probably in front of rather than actually part of the neb).
Edit: PLN corrected to PN (thanks Andrew), sorry for the newby incorrect terminology .
Wish List:
Blue Snowball
Blue Planetary
Ghost of jupiter
Blinking Planetary
And many more.....
Last edited by NQLD_Newby; 11-09-2007 at 09:01 AM.
A couple of my favourites are IC418 (Red planetary), NGC 3242 (Ghost of Jupiter) and NGC 246 in Cetus. NGC 246 hasn't had much of a a mention, but I think it's quite pretty. In a scope over 15" under dark skies, you see the mottled structure in it and it reminds me of one of those clear jelly blubbers you see floating in the river where you see the 4 transparent quadrants.
Yes, you are quite right in mentioning NGC 246 in Cetus, and it is indeed among the true "bread-and-butter" planetaries in the sky. This is a lovely object, especially for its fair size and its very pale blue colouration. It is probably just visible in 10.5cm, and my observation of a few years ago in 20cm I also saw some faint mottling features across the sizeable disk - especially with averted vision. I saw the grand colour as powder blue - not as prominent as some - but at least it is subtle. The star on the NE edge certainly enhances the object. I also like the comparison with the brightish 11.8b magnitude galaxy, NGC 255 also roughly 0.9 degrees NE and roughly about one-quarter the size.
It will sadly not make my Top 10 (unless we make it the Top 20), but I will make sure to add it to my "Honourable Mention" list...
Pleased to hear you have found the subtle beauty of planetary nebula. You have selected some great objects to start with, and in time you'll probably see those on your wish list and probably a few more. Ie. NGC 1360 in Fornax and even NGC 1535 in Eridanus. Those new ones that you do find I'll be interested to hear about.
Cheers
Andrew
Note: As a very minor comment, the abbreviation "PLN's" is probably better expressed as PN or PNe - the latter being the genitive use of the term planetary nebulae. Still anyway, we do know what you mean!!
I looked at three PNe last night, NGCs 6751, 6891 and 6905. I liked 6905 the best. NGC 6891 was very small and fairly bright through a 12" Dob at 188 times.
NGC 3918 in Centaurus is cool as. Perfectly round blue orb and it magnifies really well.
I havent observed many Planetaries but from the ones I have - the Ghost of Jupiter and the Spiral Planetary in an 8", the Dumbell and the Ring are my favourites.
Next up on my hit list is NGC 1360, NGC1535, and the one in M42.
[quote=AJames;252047]John B (ausatronomer),
Yes, you are quite right in mentioning NGC 246 in Cetus, and it is indeed among the true "bread-and-butter" planetaries in the sky. This is a lovely object, especially for its fair size and its very pale blue colouration. It is probably just visible in 10.5cm, [ /quote]using my 11.4cm scope I was able to *just* see it from my light polluted backyard (LM ~ 4.5-5)
I have in my software several in the area of M42 Glen, (although SAB did say in M42)
IC 418 as you mentioned,
IC 2165 in Canis Major
IC 2022 in orion
IC 2346 in Monoceros although this one is a little further away.
IC 2013 in Eridanus also further away
IC352 in Eridanus
IC 1535 in eridanus
Now the question is...... which one is SAB referring to......if any of these .
I guess I'll have to wait until SAB replies to your post, to find out. Or I could ask the nearest female, they seem to be good at mind reading .
This tread was great reading. i had a good look at 6337 in scorpio for the first time the other day (it's amazing what you can miss in scorpio!). Also i never thought of M27. i always thought it was too low in the north. my new OIII helps me alot with PLs. anyway i'm looking forward 2 tracking down the rest of the top 10. Domenic
The open cluster NGC 6067 and the PN PK329-2.2 = Menzel 2 (mag 12.0, diam 25") are an interesting pair. They are only 45' apart and there is a mag 5 star between them. There is a description here: http://astronomy-mall.com/Adventures...ace/soplan.htm
The PN is also in Hartung (2nd ed) page 295. The map below is for 8pm from SkyMapPro.
Oooh ... thanks for putting this thread back up Glen
Some other ideas for our next viewing night.
Was showing the Ring Nebula to the public on Wednesday, in pretty light polluted skies - it still looked great, and they were very impressed.
NGC 5844 and NGC 4071
(thanks Andrew), sorry for the newby incorrect terminology 
.
The often forgotten wonder...
This is a lovely object, especially for its fair size and its very pale blue colouration. It is probably just visible in 10.5cm, and my observation of a few years ago in 20cm I also saw some faint mottling features across the sizeable disk - especially with averted vision. I saw the grand colour as powder blue - not as prominent as some - but at least it is subtle. The star on the NE edge certainly enhances the object. I also like the comparison with the brightish 11.8b magnitude galaxy, NGC 255 also roughly 0.9 degrees NE and roughly about one-quarter the size.
.
.
