Planetary Nebulae

[glenc]

Planetary Nebulae are usually small and often difficult to find by star hopping.
They are the remains of a star that exploded and have a fairly short life.

The attached file lists 71 NGC and IC PN by magnitude and by size.
All the objects are brighter than mag 13, larger than 12" and south of Declination +50.

The columns are
Name NGC or IC
PNG galactic coordinates and name
RA and Dec. Right Ascension and declination (dd is dec in deg)
L" length in arc sec
Dist. approx distance in light years
Type. 1 stellar, 2 smooth disk, 3 irregular disk, 4 ring, 5 irregular form, 6 anomalous form
Mag of PN
Mag of central star
S.B. surface brightness
CON Constellation

Please post your observations of some of these PN.

[glenc]

Here are the latest PN distances in light years from the Gaia spacecraft.
The magnitude of the central star is also given.

[glenc]

The Helix nebulae is the largest bright PN.
It was discovered by the German astronomer Karl Ludwig Harding with a 4” refractor in about 1824.
The PN is mag 7.6, diameter 22’, 655 light years away and only 10,600 years old.
My 9x50 finder shows the PN 1.2 deg from mag 5.2 ups Aqr, and its central mag 13.5 star is easily seen in my 12” Dobsonian telescope.
A UHC filter improves the telescopic view. The nearby mag 11.1+11.5 star pair are 19.6” apart. (In the image they are below the PN)

The attached image is from Aladin.

[Saturnine]

That's quite a list to work through, should keep some of us amused for a year or two, I quite enjoy hunting down planetary nebs. Mind you I like hunting down double stars as well and the two can be happily combined while star hopping around. Can probably tick off a few dozen on the list already.
Thanks for posting the list.

[mental4astro]

Glen, excellent resource. Thanks for posting it! :thumbsup:

Also, there is a surprising number of planetary nebulae that are visible from under urban skies! And modest aperture, say up to 8" or 10" from the big smoke is VERY effective. An Oiii filter is a big help not just fixed in place in the eyepiece or filter wheel or slide, but also in a blinking paddle to swish between eyepiece and eye to help with tiny PN's to POP out.

A couple of weeks ago during this StayAtHome period, I was inspired to do a PN sketching marathon after my good friend Sergei Antonov mentioned that he had pinned many PN's from his home also in Sydney. So over two nights I managed to sketch 24 individual PN's, as it happened to go an even dozen on each night. Each night the sketches were done in two sessions - the first from 8pm to around 12am, and then from 2:30am to twilight as other PN's slowly came into view. And of course, in 6 months time another set of PN's comes into view.

With my 9" Maksutov, I used the one eyepiece for the sketches, a Vixen 12mm SLV, as it made for consistency of magnification, AFOV, contrast and context between sketches. The exceptions were for IC 5150 and the Helix where I used a Vixen 14mm SSW and a Vixen 25mm plossl respectively. These two PN's presented particular challenges that meant a different eyepiece was better suited, especially the Helix - it is so large and so faint that I used five different eyepieces to find one that gave the best image from my home in Sydney.

You will also notice that the PN's on the most part are not centred in each sketch. I wanted to also present the star field that gave the most interesting composition with each PN.

NGC 3699 is a particular fav of mine because it resembles a mini Centaurus A.

What was most remarkable for me was just how much detail can be seen in these PN's from under Sydney skies!

One thing that does have a big impact on all DSO's regardless if it is from a dark sky or urban skies, is quality of transparency. I had viewed NGC 6302, the Bug Neb., just a couple of nights before, and I could see more detail on that night as transparency had been better then than on the night I sketched it. So don't just look at a PN on one night and then forget about it. Revisiting it could mean scoring a night of very good transparency and pulling even more detail from it!

Sketches were done at the eyepiece using white and blue soft pastels on black A3 size paper. Each circle is approx the size of a fist.

Alex.

[glenc]

Thanks Jeff and Alex.
Your sketches are great Alex, done from Sydney too with a filter.

[gaseous]

Thanks for the list Glen, very useful. Are PNs stars that have actually exploded? I thought they'd swollen and shed their outer gases before condensing into white dwarfs with the surrounding nebulosity. Back to school for me obviously.

[mental4astro]

Pat, what made you reconsider what PN's are from your initial thinking?

PN's are not super nova remnants. They are as you said the nebulosity left after a star has shed its outer layers, leaving behind the star's core, now termed a white dwarf. But not condensing back to form the white dwarf.

The white dwarf is not a star in the normal sense that is converting hydrogen into helium - its fuel has been depleted which is what triggered the disastrous shedding of a major % of its mass. The white dwarf is really nothing more than a cinder that is glowing from the residual energy created/generated inside the core eons ago, and is slowly bleeding out this energy until it has no energy to release and is a dead, cold and dark mass.

It may or may not have any of its original planetary system left still orbiting the cold core - don't forget that the planetary nebula phase saw an enormous amount of the star's mass lost, in turn meaning its also lost a huge amount of its original gravitational power, so much of the original solar system may have been also lost as the core alone does not possess the gravitational pull to retain the solar system - planets, comets, asteroids, etc.

Makes you wonder what a spent, cold stellar core looks like? :question:

On the matter of stellar evolution (& sorry, a digression from the topic as this thread as sparked a question not totally unrelated though), what's with the stars that form globular clusters? These clusters are very ancient, but the component stars seem to defy what we know as typical stellar evolution - these stars should have gone past their main sequence phase a LONG time ago, yet so few PNs are ever seen in GC's and yet these stars keep shining, larger than our Sun, much older than our Sun, but still not evolved beyond main sequence... :question:

Alex.

[gaseous]

Hi Alex,


in Glen's original post he mentions that PNs are the remnants of stars that have exploded, which wasn't my understanding of PN's, which I've done some reading on, but Glen is a well-seasoned Astro veteran who I had the pleasure of chatting with at Astrofest last year as we viewed a few PN's with my scope, so I figured I must have gotten my facts wrong at some point. The idea of a cold white dwarf, or "black dwarf" as they call them, is intriguing is as much as the universe allegedly hasn't been around long enough for a white dwarf to fully cool to this stage. Again, this is only what I've read. As for the stars in GC's, I'll be pleading full ignorance on these beasties.

[mental4astro]

:lol: I hadn't noticed that! :lol:

But no, not exploded stars as in super novae. A Planetary Nebula is what our Sun will produce, but won't explode. The ejection of the layers that surround the core I guess could be considered an explosion, but this is not the same thing as a star going super nova.

[gaseous]

Yeah, that was my understanding. Lovely sketches, by the way.

[glenc]

You are right, exploded is the wrong word

[gaseous]

I caught the following PN's from Glen's list when I was at Warwick in March. First time I'd seen Cleopatra's Eye (NGC 1535) - absolutely amazing under dark skies with decent aperture. You'll have to forgive my rudimentary and "low-tech" descriptions.



NGC 2867 – Mag +9.69 Planetary nebula in Carina. Quite a decent size, very bright blue-grey disk, visible without a filter. No central star visible.


NGC 1535 – Cleopatra’s Eye Mag +9.39 Planetary Nebula in Eridanus. Very bright and quite large, no filter required to view. Central star was visible, plus an outer circular shell with an additional diffuse outer nebulous halo. One of the evening’s highlights.


NGC 2392 – Eskimo Nebula Mag +9.19 Planetary Nebula in Gemini. Very bright and better viewed with no filter to better reveal the central white dwarf. There were easily visible concentric rings of nebulosity of varying densities – a very impressive PN.


NGC 2371 – Mag +11.19 Planetary Nebula in Gemini. Small but reasonably easily visible, it seems to have two lobes, separated by a darker gap.


NGC 2899 – Mag +12.19 Planetary Nebula in Vela – Diffuse but reasonable large thin grey oval cloud, shows up well with OIII.


NGC 2022 – Mag +11.69 Planetary Nebula in Orion – Small smoky disk, easily seen.


NGC 3195 – Mag +11.50 Planetary Nebula in Chamealeon – Small bright grey ball, slightly mottled appearance.

[glenc]

I agree with Patrick, 1535 and 2392 are great.
2371 is difficult for me.


I usually observe PN with a 12" Dob at 320 times without a filter.
With the Helix and Dumbbell I use 115x and a UHC filter.


The attached file is 70 PN sorted by surface brightness.
It is the same 70 PN as in the other lists

[glenc]

This book is the PN bible

Visual Observations of Planetary Nebulae

Kent Wallace

https://www.webbdeepsky.com/publications/books/

I observed with Kent in California in 2006

[Merlin66]

Using a small 60 deg prism at the eyepiece a la Hartung helps identify smaller PN in the FOV.
The PN is seen as a point of light, field stars show small spectra.

[gaseous]

Looks like required reading Glen - I've emailed Webb Deep Sky Society to enquire about getting a copy, as they seem hard to come by. Ken, is that a DIY prism setup?

[Merlin66]

Yeah,
A film canister and a 60 deg prism.
works well.

[glenc]

M27, the Dumbbell Nebula, NGC 6853
This PN is magnitude 7.5, diameter 8’x6’ and 1230 light years away.
Its central star is a mag 14 white dwarf.
The PN was discovered by Charles Messier using a 3.5” refractor on 12 July 1764

M27 is obvious in my 50mm finder and looks like an apple core in a telescope without a filter.
The PN is best seen with a UHC or OIII filter, its age is between 10k and 15k years

The attached image is from Aladin and the map is from SkyMapPro.

[gaseous]

Ordered a copy yesterday - jeez the exchange rate and postage are killers.

[gaseous]

Received my copy on Friday - indeed, it is the bible for PNs! I was sort of hoping there might be a few pictures included, but there's nary a photo to be seen anywhere in its nearly 500 pages. There also appears to be no rhyme or reason in terms of how the PNs are catalogued, so you need to utilise the index at the back if you have a particular object you want to look up, otherwise it's just 800+ descriptions/notations one after the other. That being said, if you can't find the PN you want in this book, you're very hard to please. The author also found a lot of them with a 20" scope, so there is a challenge in that respect also. I wonder if there's a SkySafari list for all these.....

[glenc]

Patrick are they ordered by galactic coordinates?

The Strasbourg-ESO Catalogue of Galactic Planetary Nebulae (Acker+, 1992)
is available as a pdf online.
Part 2 is 752 pages and 36.2 MB
Part 1 has images but I haven't seen it online.
I have a hard-copy of both parts.


"... a list of 1820 objects, each of them called at least once a planetary nebula, have been inspected; 1143 of them have been classified as true or probable planetary nebulae; 347 objects, which status is still unclear, were classified among the "possible" planetary nebulae. Finally, 330 objects have been rejected."

[gaseous]

Ah, yes Glen, that makes sense - that's how they're ordered, thanks.. I'll have a look online at those docs you mentioned. I'm also in the process of creating a Skysafari observing list if anyone is interested.

[glenc]

I saw 24 PNe last night between 12:30 am and 1:30 am with my 12" Dob using a 9mm EP with a UHC filter and a 4.7mm EP at 167 and 320 times respectively.


* These PNe were faint
*IC 1295, *IC 5148
M 27, M 57, *Mz 2
*NGC 3195, NGC 5189, NGC 5882, *NGC 6072
NGC 6153, NGC 6210, NGC 6302, NGC 6326,
*NGC 6337, NGC 6369, NGC 6445, NGC 6563
NGC 6572, NGC 6629, *NGC 6781, NGC 6818
NGC 6905, NGC 7009, NGC 7293


The image below shows NGC 6712 and IC1295
It was taken by Mike Keith

[gaseous]

Some terrific targets there Glen - you must have some nice skies where you are.

[glenc]

Observations
Date Sunday 19 July 2020, dark from 6:30pm to 5:15am on 20 July 2020
Observed 3 times. 6:30pm to 9pm, 12:30am to 2am and 4am to 5:15am (total 5¼ hrs)

Location 8.5 km west of Lismore, NSW (28.8 S, 153.2 E, alt 45m)
Good horizons W, N and E with some light pollution on the E
Hill on the S side, but the SCP, LMC and SMC were still visible
Fog in the valley and dew on the hill where I was observing
Used a hair dryer to dry the secondary and EPs many times.

Telescope 12” collapsible Saxon Dobsonian, focal length 1500 mm (not goto)
Eyepieces 26mm (58x), 11mm (136x), 9mm (167x), 4.7mm (319x)
Used a UHC filter on the 9mm EP for large PN and most nebulae
Used a UHC filter on the 26mm EP for large nebulae (Lagoon, Veil, North America)
Also used 15x70 Celestron binoculars on the Milky Way, LMC, SMC, M31, M33

Made a list of DSO I had seen after I got home, saw about:
19 open clusters, most seen with the 26mm EP
50 globular clusters, most seen with the 11mm Explore Scientific EP which has an 82 degree apparent field of view
28 nebulae, seen with the 9mm EP and 26mm EP both with a UHC filter
Also scanned the SMC and LMC for clusters and nebulae with the 11mm EP
37 planetary nebulae, seen with the 9mm+UHC and 4.7mm Explore Scientific EP (82 degree apparent field of view)
64 galaxies, most seen with the 11mm EP
198 total + lots of objects in the Magellan Clouds

Also saw Jupiter, Saturn, Mars and Venus with the 9mm and 4.7mm EP

The 37 PN were
M27 M57 M76 Mz2 NGC246
1360 1535 2867 2899 3132
3195 3242 3699 3918 4361
5189 5307 5882 6072 6153
6210 6302 6326 6337 6369
6445 6572 6781 6818 6905
7009 7027 7293 7662
IC1295 IC4406 IC5150


Photos view to the North/NE and view to the East.

[gaseous]

You've set a cracking pace there Glen! That's a very impressive list and a massive night's work.

[gaseous]

After several days of contradictory cloud forecasts from the ever-unreliable ClearOutside app, I made my way to Warwick last night with SEQAS. The skies were magnificent and clear until the clouds began rolling in around 1.30am, but it was my bedtime then anyway as it was freezing.

I checked out a few of the more noteworthy PN's: Ring, Dumbbell, Skull, Bug, etc. I had the Ring at 500x trying to spot the central star – a challenge laid down by Stephen James O’Meara in this month’s Astronomy magazine, but apart from a brief moment of averted imagination, I think I drew a blank. I then then decided to try a few of the less well-known versions. I was using SkySafari to list all PN's, then was simply going to ones I've never seen before. There's a reason they're not well known - generally they're pretty hard to spot and aren’t especially mind-blowing, even with a filter and a good idea of the local star layout, but there's a certain satisfaction is nabbing them nonetheless. Excuse the brief descriptions - it was too cold to have hands exposed for any longer than necessary. Equipment was a 20” GOTO dob, 8-24mm Baader Zoom, 3-6mm Nagler zoom, Lumicon OIII filter and DGM NPB filter.


Minkowski 3-34 VM +12.6: Faint stellar dot
YM 16 VM +13.0:Very faint stellar dot
Sharpless 2-17 VM +12.3: stellar dot
Minkowski 1-66 VM +13.3: dim blue stellar dot
PK 033-05.1 VM +13.19: very pale faint grey puff, needs OIII and averted vision.
NGC 6778 VM +12.1: Not quite stellar sized blue-grey mottled disc with a blurred edge
NGC 6790 VM +10.69: Stellar dot
Merrill 2-2 VM +11.5: tiny faint stellar dot.
NGC 7662 Blue Snowball VM +8.30: Intense bright blue ball of good size, OIII suggests fainter outer nebulosity
NGC 6565 VM +11.39: small dot, needs OIII to really pop out.
NGC 261 VM +13.0: small bright puff of nebulosity
NGC 6072 VM +11.3: reasonable sized grey disc easily seen. No real distinct edges – blurs towards the edge.
Cannon 1-1 VM +12.89: Stellar dot
Henize 2-118 VM +12.69: small dot, OIII helps to resolve it.
NGC 5873 VM +11.19: Quite small but relatively bright ball
Wray 16-210 VM +12.0: small but quite bright grey disc with a hint of elongation and rim brightening.
Henize 2-141 VM +12.3: very small grey blob, needs OIII.
Wray 16-183 VM +12.00: small grey disc with a suggestion of a dark hole in the centre. An image on Skysafari confirms a donut/ring-like appearance.
ESO 3-0 VM +11.35: tiny faint mottled splodge.

[glenc]

That is an impressive list Patrick.
I observed from Leycester, NSW on Sunday and Monday night.
It wasn't as cold there.

[DeepSkyBagger]

Hi All,

I'm located way up at N53.5 degrees, but I've made observations of 39 of Glen's PNs. Each observtaion has a description and a sketch. I could put them up here if anyone's interested? A few each day for a few days?

[jahnpahwa]

I'd be keen to check them out, yeah :)

[glenc]

Please do.

[gaseous]

Absolutely!

[DeepSkyBagger]

OK, thanks for the enthusiasm. :) I'll start with three, just to see how they go. They may be a bit large and I may have to reduce them in size a bit. Please tell me if they're too big.

1. NGC 6853 (M27) Vul.
Huge and very bright. The brightest area was the southern half of the 'dumbbell', which was an irregular oval in shape. This had uneven surface brightness and several brighter knots. The northern dumbbell was larger and more triangular in shape. The 13.8 mag central star was clearly seen with averted vision and appeared to be in a slightly darker inclusion.

2. NGC 3242 Hya.
Very, very bright. The object responds well to the OIII filter. At x150 the nebula is clearly slightly elongated and there are hints of annularity. At x450 a darker centre is seen, with a brighter patch on the south side of the nebula. A thin outer area of pale nebulosity can also be seen. Amazing.

3. NGC 7293 Aqr.
Not visible without the OIII filter in place. Huge and dim. Obvious but quite difficult to pin down the elusive details. The outer edge of the ring is almost circular, whilst the inner edge appears more elliptical. There is a distinctly brighter patch in the north-east segment of the ring, and fainter areas at the extremities. (Bear in mind that I made this observation from southern Scotland. The object was transiting and had reached its maximum altitude of 15 degrees above the horizon.)

[gaseous]

Lovely sketches Patrick. How do you sketch and maintain your dark-adapted vision?

[DeepSkyBagger]

Hi Patrick,
I make rough sketches at the eyepiece plus copious notes. Then the following morning I make a more refined version (pencil on white paper). I invert them using an image manipulation program. For illumination I use a very faint red light. So faint that I have to hold it within an inch of the paper to see it at all. I use 4" diameter circles, and have to move the light around to illuminate each part of the circle I'm drawing in.

[DeepSkyBagger]

The first three seemed to go quite well. Here's the next five.

4. NGC 7009 Aqr.
Very, very bright. Instantly visible in medium finding powers (x83). Quite elongated with lobes at either end. There is a darkening within it, but it is not central, so not a hole, I think. (see 98/01). There is faint outer nebulosity, which extends to form the 'ansae', though these are usually visible only to averted vision. The OIII filter makes it appear a little larger, presumably by brightening the fainter outer nebulosity, but it is really not needed for this object.

5. NGC 7662 And
Very, very bright. Quite elongated. Pale blue in colour. Darker in the middle, making it appear annular. Faint extensions are visible outside the brighter part of the nebula. There is a brighter ring structure within the bright nebula.

6. NGC 7027 Cyg
Very bright and very small. It appears rectangular in shape. The northern half is brighter than the southern, with an intense bright spot in the north west. A dark line bisects the nebula across its shorter dimension, half way along. At x450, the OIII filter reveals a fainter outer nebulosity. The filter does little for the brighter part of the nebula. Stands very high power very well, under which it appears a little more rounded. The western edge is sharper, the eastern edge tending to fade away as if ‘brushed’.

7. NGC 6210 Her
Very, very bright, obvious at x83. The OIII filter adds nothing. Bright blue. Fairly homogeneous, slightly elongated. The north side is brighter than the south side where there is some sort of darkness. Outer nebulosity is visible, especially at the extremities of the nebula.

8. NGC 6720 (M57) Lyr
An astonishing view at x450. The colours were quite bright - greenish in the ring and bluish inside. Of course, I may be influenced by photographs. With colour vision as bad as mine it's hard to tell. I think for the first time, I actually glimpsed the central star with averted vision.

[jahnpahwa]

These are so good, and the descriptions too :)
Are you pushing to these targets?

[DeepSkyBagger]

Some of the observations were made with a 12" scope on a simple Dobsonian mount, others with a guided Goto scope. I have to say that the Goto on the 12" SkyWatcher that I have is not all that good, and finding objects usually involves some 'micro-star-hopping'. The Goto will get me within a degree or so of the object, then I hop along to it.

Here's the next five.

9. NGC 6826 Cyg
Very bright. Three distinct areas visible. The centre is almost starlike and extremely bright. This is surrounded by a very bright, smooth, almost circular area. Outside this is a dimmer area, which nearly doubles the apparent width of the object and gives it a clear elongation.

10. NGC 2392 Gem
Very, very bright and intensely blue. One of the very few DSOs that show a distinct colour to my eyes. Brilliant central star, very bright central region and bright outer region. The inner region is almond-shaped whilst the outer is round. Very mottled all over. Superb object.

11. IC 418 Lep
Bright, small and stellar at medium power. High power reveals a brighter area in the middle and a clearly oval shape. The nebula appeared to be pale blue in colour.

12. NGC 2440 Pup
Very bright. Greenish. An elongated outer nebulosity with a brighter inner nebulosity elongated at 90° to the outer. No central star seen, unsurprising as it is magnitude 18.9.

13. NGC 1535 Eri
Bright. Immediately obvious, even in medium power. Round with a brighter centre. Brighter with OIII filter.

[glenc]

Thanks Patrick for the great descriptions and drawings

[DeepSkyBagger]

Thanks, Glen. To be honest, it's a pleasure to be able to share them with someone! Alright, here's the next five:

14. NGC 6818 Sgr
Very bright and easy. Visible as a small disc at x83, it actually looks like a planetary disc. The brightness is fairly even, but there is a hint of brightness at the centre. The OIII filter is not needed for this object, and adds nothing to the view.

15. NGC 246 Cet
Very large but pretty faint. Although this planetary nebula has a magnitude of 10.9, it appears very dim because of its low altitude (24 degrees at the time of observation). Three stars were seen to be involved. It appears as an oval disc, elongated roughly N-S with uncertain edges. A darker patch could be seen near the middle. The nebula was barely visible without the OIII filter, the stars were barely visible with.

16. NGC 6891 Del
Very bright, but not much more than stellar at x150. At x450 there is a very bright stellar condensation (possibly a central star) surrounded by a bright disc with fainter extended extremities, which are easily seen with averted vision.

17. IC 2149 Aur
Tiny. Elongation suspected and this was confirmed at x450. There is a bright middle with a slightly fainter periphery. No further detail was discernible.

18. IC 4593 Her
Very bright but very small. The effect of the OIII filter was marginal. Stellar at x83. Blue. The bright central disc was enhanced by faint, elongated ‘wings’ of nebulosity. A bright stellar point was seen, though this is off-centre.

[DeepSkyBagger]

Is this getting a tiny bit boring now?

19. NGC 1514 Tau
Only the bright central star (m9.4) was visible without the OIII filter. With the filter, the nebula presents as a bright, circular disc, brightening towards the central star. It fades away gradually at the edges.

20. NGC 6905 Del
Very bright and very large. It is quite circular and appeared blue. A small central star comes and goes. There is a distinctly brighter patch of nebulosity in the north east. Darker regions to the sides and a brighter band across the nebula make it fascinating to look at and quite beautiful.

21. NGC 7026 Cyg
A tiny spot at x83. Clearly visible at x150 as a small disc with a brighter centre. x375 shows two bright central areas within the nebulosity, which is clearly elongated.

22. NGC 4361 Crv
Pretty bright for its altitude (16.5°). Circular with a bright centre. A central star pops in and out of view. There was possibly the occasional glimpse of a ring structure.

23. NGC 2371/2 Gem
This object looks like two circular nebulae in contact. It looks like a small M76. The more southerly nebula is brighter and has a very bright centre, the other is less condensed. Brighter when seen through the OIII filter. Under very high power (x450), a dark area is visible between the two halves, with a central star (15m) in it.

[glenc]

It is not boring Patrick
Excellent work

[gaseous]

Not boring at all - excellent sketches, and very motivational.

[jahnpahwa]

NGC6905 sounds great. I'm not bored either :)

[DeepSkyBagger]

Many thanks for your comments. Yes, NGC 6905 is a beauty. The brighter and darker regions give it a waisted appearance, and I was struck by its resemblance to a little M27. Here's some more:

24. NGC 2438 Pup
Beautifully located in the open cluster M46, though apparently only as a foreground object. Large and oval. There is a void in the centre and the south-eastern side is brighter than the other.

25. NGC 6309 Oph
Moderately bright. Small and mostly round, but often appears elongated. It is brighter with the OIII filter in place, which also reveals some structure. It is brighter in the middle with an area of faint outer nebulosity. There appears to be a brighter spot at its southern edge. The star to the object's north is not visible through the OIII filter.

26. NGC 6369 Oph
Although I observed this object at transit, it was only 12° above the horizon, and it was not visible without the OIII filter. Small, brightish and circular. The surface brightness looks uneven, being brighter on the north to north-west edge. Averted vision gives a suggestion of annularity, and there is an occasional hint of a central star. I would love to see this object under better skies.

27. NGC 6751 Aql
Fairly bright. Immediately visible at x83. At x450 it appears round and grey, sharply brighter in the middle where there is possibly a central star. The small star to the nebula’s east initially looked nebulous. The object is too dim to stand the OIII filter at x450. The filter made little difference in any case.

28. NGC 6781 Aql
A very odd-shaped nebula. The southern end is brighter with an almost cometary tail to the north. There is a brighter section to the south-east. Fairly large and visible without the OIII filter at x83. The OIII filter adds some detail.

[DeepSkyBagger]

Right, here's my penultimate offering of planetary nebulae from Glen's list:

29. NGC 2022 Ori
Pretty bright. Slightly elongated and darker in the middle. There is also a dim outer disc of nebulosity. A brighter spot can be seen to the south. There is no sign of a central star. The UHC filter enhances the internal structure, but the OIII filter doesn't help. It appears grey in colour to me.

30. NGC 2346 Mon
'Nebula with star'. A small, round nebula around an 11.6 mag star. Much more obvious when viewed through the OIII filter. Very little detail. Rich field.

31. NGC 6778 Aql (aka NGC 6785)
Small disc at lower powers. Pretty faint but visible to direct vision at x83 with no OIII filter. x375 reveals elongation. Brighter in the middle, but no real sign of a central star. There is some outer, fainter nebulosity. The OIII filter increases the object’s brightness but adds no details.

32. NGC 7048 Cyg
Visible without the OIII filter as a pale grey patch. The OIII filter reveals a bright, beautiful, smooth, almost circular nebula which grows a little brighter towards the middle. A lovely object in a very rich field.

33. NGC 6804 Aql
The OIII filter was not needed for this object. It has a strange triangular shape. It is brighter at the north-east end where it is pointed and a star lies. There is a brighter area along the centre line of the object, where a second, fainter star is involved. Altogether pretty bright and visible at x83 without the OIII filter.

[DeepSkyBagger]

OK, here are the final six planetary nebulae from Glen's list that I have observed:

34. IC 1295 Sct
Pretty faint but clearly visible to direct vision with the OIII filter. Difficult without. Quite large, rounded or maybe slightly angular. Averted vision reveals hints of structure, but uncertainly. There are definite hints of a central star. I found this nebula to be astonishingly clear considering how faint it appears on the POSS.

35. NGC 6894 Cyg
Visible at x83 but only with the OIII filter in place. Annularity suspected immediately at x150 with the OIII filter. The ring structure was not always visible and was better with averted vision. Fairly faint, looking like a small ghost of M57. Nice object.

36. NGC 6772 Aql
Large but very dim, it is barely discernible without the OIII filter in place. Even with the filter, it is still difficult. It appears not quite round, being slightly elongated N-S. No variation in brightness was seen across the object.

37. NGC 6058 Her
Visible at x83. Pretty bright, especially considering the brightness of the twilit sky. Round and distinctly not stellar. Sharply brighter in the middle. Central star not seen. Use of the OIII filter increases the object’s apparent diameter noticeably. At x375 there was still no sign of a central star.

38. NGC 6852 Aql
Very dim. Only really visible with the OIII filter in place and even then difficult. It shows a medium sized disc. The centre of the disc is very bright, considerably brighter than the star to its immediate west (mag 13.2). The bright centre, which looks like a star, can only be seen when the OIII filter is not in place. It is invisible with it in. DSFG gives the magnitude of the planetary’s central star as 17.9, so what was it that I saw?

39. NGC 2610 Hya
Pretty difficult, even with the OIII filter in place. The low altitude of 19° didn't help. Quite large and circular. No structure seen. A brighter point was seen at the centre (but only without the OIII filter). This is unlikely to have been the central star which shines at magnitude 15.9.

For contrast, here's another observation I made of NGC 2610, but this time from the rather better, and more southern, skies of the Winter Star Party in Florida. This was with a 16" Newtonian:

Bright and easy. Initially, this object was perceived as a disc, but further investigation revealed a darker centre, giving the object an annular appearance. Elongation estimated in PA about 50°.


Well that's it. I haven't seen any of the other PNs in Glen's list, though I have seen about another 60 he doesn't list. My horizons are limited. Theoretically, my horizon due south is at declination -36°, but light pollution means my realistic horizon is closer to declination -10° or -15°.

I would love to explore the southern sky as I have the northern, and I remember well the pristine skies of the Australian Outback that I experienced back in 1986 when I went there to see Halley's Comet. I didn't have a telescope, of course, only binoculars.

Some day...

[glenc]

Thanks Patrick for an excellent collection of descriptions and drawings.