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Ring Nebula

NGC 6720, PK 063+13 1, PN VV 214, PN G063.1+13.9, HD 175353, Messier 57, Ring Nebula, h 2023, GC 4447

RA: 18h 53m 35.08s
Dec: +33° 01′ 45″

Con: Lyra
Ch: MSA:1153, U2:117, SA:8

Ref: SIMBAD

(reference key)

Type: planetary nebula

Mag: B=14.7, V=15

Size: ?
PA: ?

Image gallery

Sketches  (2)

Select a sketch and click the button to view

Photos  (2)

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Historical observations

Darquier

Discovered in 1779 by Antoine Darquier, who described it as "a perfectly circular disk as large as Jupiter, but dull and looking like a fading planet."

William Herschel (c.1784)

In the Philosophical Transactions, 1814, Herschel described it as "an oval nebula with eccentric oval dark space in the middle; there is a strong suspicion of its consisting of stars. The diameter, measured by the large 10 feet telescope, is 1' 28.3 arcseconds." In the Philosophical Transactions, 1818, William Herschel wrote: "1782, 7 feet telescope. I suspect it to consist of very small stars; in the middle it seems to be dark. 1783, 1805, 1806, 10 feet telescope. With 130 it seems to be a rim of stars, but with 350 power there remains a doubt. It is a little oval; the dark place in the middle is also oval; one side of the bright margin is a little narrower than the other. 1784, 1799, 20 feet telescope. It is an oval with a dark place within; the light is resolvable. 240 power showed several small stars near, but none that seem to belong to it. It is near 2 minutes in diameter. 1805, large 10 feet telescope. By a merdiain passage of 7 seconds of sidereal time, the diameter is 1' 28.4 seconds."

Burnham, S.W. (1894)

Burnham, S. W. () "Measures of planetary nebulae with the 36-inch equatorial of the Lick Observatory", Pub. Lick Obs., vol 2, p159-167. When the seeing was the best, and perfect for all practical purposes, the ring and the darker interiori were carefully examiend with various powers, but without detecting any other stellar point. In various places there are minute areas of slightly brihgter nebulosity, but none of them appear to be stars.

NGC/IC Dreyer (1888, 1895, 1908)

The NGC describes it as a magnificent object, bright, pretty large and considerably extended.

Published comments

Bailey, S.I. (1908)

"! nebula, ring, elliptical, nucleus; The wellknown Ring nebula in Lyra"

Bailey, S.I. (1908) A catalogue of bright stars and nebulae. Ann.Harv.Coll.Obs., 60(8), 199.

Remarks, p.218: "the spectrum is gaseous."

Doig, P. (1925)

Doig, P. (1925) Notes on the nebulae and clusters in Webb's 'Celestial Objects for Common Telescopes' (Sixth edition, Vol.ii). Part II. M.N.R.A.S., 35(8), 280.

Sulentic & Tifft (1973)

The RNGC (Sulentic and Tifft 1973) notes that this is a 9.5 mag planetary nebula.

Terzian, Y. (1980)

Terzian Y (1980) Q.J. R.astr.Soc vol 21, p82-92 [09.16.1] notes that this planetary is considered to be a proto-planetary or very young planetary nebula. It is an infrared source, indicating the presence of dust in the envelope.

Modern observations

[amastro] M57 central star visibility

Following on the the s.a.a. discussion about the visibility of the central star of M57, I looked into the historical literature a bit to find out if there were early observations with small apertures.

There was quite a lot of work done on the central star and the field stars by Barnard in the Monthly Notices. But this was with the Lick 36-inch refractor, and basically irrelevant.

However, there is a long report by Holden in MNRAS 48, 383 (1888) that contains some interesting comments. Drawings by John Herschel, D'Arrest, Trouvelot, and Lord Rosse do not show the central star. Lord Rosse's drawing was made with his early 3-foot speculum reflector, not the later 72-inch. In 1860 Lassell used his 4-foot telescope to measure the field stars, and includes the central star as his no. 14. Asaph Hall, using the USNO 26-inch refractor made additional micrometer measurements, but does not mention the central star, except to say "I could see no star...within the ring of the nebula itself." (This was in Astron. Nach. no. 2186.)

Holden found this last comment inexplicable, noting that the central star "...has been well seen by Professor Schultz at Upsula [Uppsala, Sweden] with the Steinheil refractor of 9 1/2 inches, and is seen here [Lick Observatory] with the 12-inch equatorial." Alas, no citation to the Schultz observation.

Holden's continuing description includes what is apparently the first observation of the companion to the central star, first observed by Schaeberle at Lick. It is noted as being doubtful, since only Schaeberle could see it--- meaning merely that Holden was not as good a visual observer.

I note also that Steve O'Meara has seen the central star using the 9-inch refractor at Harvard (a distinctly _urban_ observing site); see his recent book for details.

Brian

------------------------------------------------------------------------

Hi All

Although a sighting of the M57 central star with a driven 24" reflector (f/8 Ritchey-Chretin belonging to Tim Puckett of Mountaintown, GA) at 350X won't surprise anyone, I did notice a peculiar twist to this observation. The central star would be a fairly easy direct vision object at first glance through the eyepiece and would then become increasing difficult as the gauzy interior nebulosity of the ring became more apparent. I suppose the central star would be overwhelmed by the nebulosity as my eye became slightly more dark adapted... Seeing conditions were quite good that evening as we could use powers of 1000X without trouble.

Dave Riddle

------------------------------------------------------------------------

At 04:38 PM 6/12/99 -0700, Skiff wrote:

] I note also that Steve O'Meara has seen the central star using the

9-inch

]refractor at Harvard (a distinctly _urban_ observing site); see his recent

]book for details.

I think Brian and I have talked about this already, but I've been chasing the central star with various apertures and under various conditions for the last three or four years, trying to get my own impressions about what conditions influence its visibility.

I'm nearly convinced that the dominant variable is seeing conditions. I'm also pretty sure that sky brightness does not matter much, within reason at least. The smallest telescope I've ever seen the star with was my own 10" Newtonian, from my (current) backyard observing station, on the same night that I made the Mars observations that were printed up in the latest Sky&Tel. Recent observations with Glen Sanner's 18.5" (at TSP this year), Dave Healy's 14", and most recently in Dave's troublesome 16" SCT (last night), were all made under seeing conditions that can only be described as outstanding. Unfortunately, there are not enough of these nights to see the star consistently.

By contrast, I have failed completely to see the star in all of the aforementioned telescopes, as well as with 31", 36", and 42" scopes, and a whole lot of others, under indifferent seeing conditions.

Some of my observations of the star have been made from south Sierra Vista (moderately bright), the Astronomy Club of Akron, Ohio site (bright!), and various other locations that are not great deep sky sites. The center of the Ring is already bright; perhaps this is one reason it doesn't seem to matter so much.

--

Jeff Medkeff

------------------------------------------------------------------------

Message text written by "Jeffrey S. Medkeff"

]I'm nearly convinced that the dominant variable is seeing conditions.<

Jeff,

I couldn't agree with you more. I've seen the central star several (I wouldn't say "many") through my 18 f/4.5 scope, but each time, the critical common thread was seeing conditions. Indeed, my notes recall that the first time I spotted it with the scope was from my decidedly suburban backyard here on Long Island (typical naked-eye mv = ~5). But the seeing that night was one of the steadiest that I recall in my 15 years of living here. Ironically, I've tried for the star several times from darker locations (e.g., Stellafane), but without success.

Phil

------------------------------------------------------------------------

this is about the same as the discussion is going on saa as well. I agree 100%. The stars surrounding m57 are crucial to be visible first, and I have done some very rudimentary photometry and linked it with Brian's article. My picture with the magnitudes is at

http://www.weatherman.com/m57.htm

]I couldn't agree with you more. I've seen the central star several (I

]wouldn't say "many") through my 18 f/4.5 scope, but each time, the critical

]common thread was seeing conditions. Indeed, my notes recall that the

]first time I spotted it with the scope was from my decidedly suburban

]backyard here on Long Island (typical naked-eye mv = ~5). But the seeing

]that night was one of the steadiest that I recall in my 15 years of living

]here. Ironically, I've tried for the star several times from darker

]locations (e.g., Stellafane), but without success.

MacRobert, Alan M

MacRobert notes that the Ring is "easy to spot as a little round smoke puff 2/5 of the way from Beta to Gamma Lyrae. With a visual magnitude measured at 8.8 it can be seen in a 2.4-inch refractor as a small disk with a darker centre. In my 6-inch reflector at 45x the disk is clearly oval, the dark 'doughnut hole' is plainly seen, and the ends of the oval look a trace dimmer than the sides. All these features become more evident at higher powers. Many planetary nebulae are unmistakably blue or green, but M57 looks gray to me. The ring is about 70 arcseconds diameter. A 12th mag star lies just off its east edge. The nebula's own central star .. is 15th mag and beyond reach visually in nearly any amateur telescope. This is especially true since the interior of the ring is not completely dark."

Hartung, E.J. (1968) Astron.Obj.South.Tel

Hartung notes it as a bright pale blue elliptical ring, 80" by 60" in PA 80. He adds that though the central star is plain in photographs, it is difficult visually, and he has never been able to see it. In medium-size telescopes, this small glowing ball looks like a smoke ring with a dark core; more challenging are the gossamer band of nebulosity that cross the core.

Bortle, John (1976)

John Bortle (Webb Society Quarterly Journal, January 1976) using 10x50 binoculars, estimates the visual magnitude as 8.7.

(unknown)

A note in The Webb Society Nebulae and Clusters Section Report No. 11, January 1993, reads: "Finally, a puzzle. Petteri [Rajanen of Kauppi, Tampere, Finland, observing with a 8-inch f/5 ] reports an observation of M57 which showed a star within the ring of nebulosity. It was etimated at mag 13-14. It was regularly seen during a week of observation; the central star was not seen." His sketch, reproduced on page 21 of the Report was made at 200 power and shows the star to the south-west of centre, within the ring.

Tom Lorenzin

Tom Lorenzin, in the e-version of "1000+ The Amateur Astronomers' Field Guide to Deep Sky Observing", notes: "9.7M; 80" x 60" extent; this astral doughnut requires higher-x to appreciate fully; midway and just S of a line between Beta LYRand Gamma LYR; too small for hand-held binoculars of <20x; 14M center star tough because of spectral class and lack of contrast in interior glow; good reference photos BCH-II-1165,6; the "RING" nebula ."

Callender, John

Observer: John Callender

Instrument: 8-inch Dobsonian reflector Location: Carpinteria, CA, USA

Light pollution: moderate Transparency: fair Seeing: fair

Time: Mon Mar 17 12:55:00 1997 UT Obs. no.: 114

As the dawn started to brighten the E sky, I turned to my first telescopic viewing of M57. It was great! The best view was at 244x, which showed the object as a big, oval smoke ring, with the hole inside the ring being noticeably brighter than the surrounding blackness.

Observer: John Callender

Instrument: 8-inch Dobsonian reflector Location: Carpinteria, CA, USA

Light pollution: light Transparency: good Seeing: fair

Time: Sun Jun 29 06:15:00 1997 UT Obs. no.: 158

I dragged Linda out of the house in her bathrobe (actually, it was _my_ bathrobe :-) to look at the Ring Nebula. I think she was too sleepy to really get into it, but she made some appropriate "oohing" and "ahhing" noises. I looked for the dimmings of the ring that are apparent at the points where it intersects the object's major axis on some photographs, but couldn't see them. I wonder if this is dependent on viewing in a particular color. I didn't see any detail to speak of in the ring itself.

Observer: John Callender

Instrument: 8-inch Dobsonian reflector Location: Carpinteria, CA, USA

Light pollution: light Transparency: good Seeing: good

Time: Tue Jun 24 06:30:00 1997 UT Obs. no.: 154

Couldn't resist a quick look at M57 before coming inside. Viewed it at 49x, 122x, and 244x (as high as I can go, currently, with the 10mm eyepiece and 2x barlow); each view was better than the last. It's an amazing object, looking pretty much like the photographs, even in my smallish scope. A thick, oval ring with the inside obviously brighter than the outside.

Shaffer, Alan (IAAC)

Observer: Alan Shaffer (e-mail: milkyway@gte.net, web: http://www.geocities.com/CapeCanaveral/3693/)

Instrument: 10-inch Schmidt-Cassegrain reflector Location: Mt. Pinos, California, US

Light pollution: none Transparency: excellent Seeing: excellent

Time: Sat Jun 7 10:00:00 1997 UT Obs. no.: 149

This was a rather easy find. M57 is positioned in a rather star poor area of the sky. At first sight I noticed the colors. It looked like I was looking at a prisim, full of color, but mostly greenish. This is a beautiful object because it sits in nearly pure dark skies by itself. The ring was easy to observe. No effort needed to see the central area, even at 104X. A very nice object

[amastro] discussion

Date: 10 Aug 1995 16:16:29 GMT

From: jtws@dalsol.rtc.sc.ti.com (Jason Ware)

Subject: Re: Correction for Star in M57

I also looked at the M-57 picture, VERY interesting. How easy is it to

see visually? scope size, seeing, filters? I have never been able to see the

central star myself, even in a 25" scope. Is the star in the bright part

easier?

---

Jason Ware..

Date: Fri, 11 Aug 1995 16:53:04 GMT

From: freeman@netcom.com (Jay Reynolds Freeman)

]I've seen the central star in M-57 with Roy Norris's 25" Obsession while

]using a 9mm Nagler. It was a very difficult object indeed and was not

]"steady". However, persistance and averted vision did reveal it.

I have logged the central star several times in my C-14, at 315x or 559x. I agree that it is a quite difficult object. I once had a look through the 36-inch Clark refractor at Lick on a public night, when M57 was the object being viewed, and I could not the central star then; the seeing was noticeably ratty at the time, though.

--

Jay Reynolds Freeman -- freeman@netcom.com -- I speak only for myself.

Date: 11 Aug 1995 18:17:12 GMT

From: darksky@shore.intercom.net

Subject: Mystery of M57

Sorry about the format of my previous message on this subject but a server problem forced me to compose and copy to email and repost at a latter time and that is how it came out: Unreadable!

I have now been able to access the site of Riku's and examined the photo. I'll look for it tonight and post the results. Incidentaly, the star CAN be detected in the Palomar blue light photo on page 1165 of Burnham's Celestial Handbook (upper photo). Of course, the site image is mirrored so comparison looking through the map I drew seems to check out precisely.

Russ

Date: 11 Aug 1995 18:42:18 GMT

From: jtws@dalsol.rtc.sc.ti.com (Jason Ware)

Subject: Re: Correction for Star in M57

In article 4mg@shore4.intercom.net, darksky@shore.intercom.net writes:

] I can't understand what accounts for this discrepency on reported

]observations of the central star

This debate has gone on for years. One theory is that the central star is very blue, and thus some people's sensitivity to seeing it is better than others. I also do not see reds in nebula such as M-42 very well. On the other hand I do see faint nebula very well and have picked out objects that others can not see.

As for it "always" being visible in a C14, I have tried on several occasions to see it in a C14 and could not. On the other hand I once showed the ring to a complete novice in the city and he said "hey look there is a star in the center". This was in a Meade 8" SCT. Go figure!

---

Jason Ware..

Date: 10 Aug 1995 18:59:57 GMT

From: darksky@shore.intercom.net

Subject: Re: Correction for Star in M57 -(65 lines)

I looked at the ring last night in Full moonlight and could see the central star with averted vision for a few seconds at a time in my 20". I can't understand what accounts for this discrepency on reported observations of the central star. In fact, a friend has a 6 inch F/8 and the other night when I brought my 9mm nagler to him, we popped it in the scope and viewed the ring. He exclaimed (and he has seen the central through my scope 1/2 dozen times),"Hey. I think I see the central star!" I advised him that at 15th magnitude and under suburban skies and embedded within nebulosity, that was HIGHLY unlikely to say the least. I took a look and if you wished hard enough at 122x, you would think that there might be a star in the middle but I know better. Having used many strategies on this star, my 20" doesn't show it at 125x and it is when I go to 555x that the star is observable. Yet, it is very easy to "see" a star in the center if one tries hard enough and I believe it is an effect of an illusion created by the Ring's structure. In truth, had I not made observations at 555x and watched the star come in and out with the seeing and compared it to the dim double that sits about 3 ' from the ring, I would think that I did see it at 125x. The thing is that the double is Not visible or divided at 125x and since it is quite easier than the central star to detect at 555x, I know that despite what I would say was a sighting of the central star at 125x, it cannot be. My opinion is that if an observer is not seeing this dim double as two stars (est. Magnitude 14.3, est. separation 5") fairly easily, the central star is out of reach. This double appears on page 1166 of Burnhams in the red light photo (lower) and is located top center of photo. It's comparative brightness appears quite dimmer in my 20" than the photo and if one imagined that the central star was on the threshold of visibility in the photo, the double would be proportionately dimmer than in the photo. I can only say that I easily divided Hussey 664 in Draco last night (Mag.8,8 0.4" and relatively fixed) with dark space to spare so my optics are sharp. Yet, the central star although visible always, is NOT easy and I have only rarely seen it with direct vision. Givin my 96% coated optics, if it appears easy to others in smaller scopes I can only come to the conclusion that my eyes are not as sensitive to dim objects and this could very well be the case. It is curious that Jason's 16" Meade does not show it when a C14 was said to always show it.There was a report of four stars being seen within the confines of the ring a month ago on this board yet an experienced observer fails to detect the central star in a 25 incher and some claim it in a 10 incher. After seeing the central star in full moonlight last night (and it was a little more difficult than usual but still seen),I feel that dark skies are not that much of a factor in seeing this object. Steadiness is a factor for holding it visually more so than detecting it. I would like to know who else does NOT see it and if seen, what power and eyepeice type. As for the mystery star, I'll give it try if I can find out where it is.

Regards,

Russ

Date: 11 Aug 1995 20:39:35 GMT

From: jlarkin@eel.ufl.edu (Joseph C. Larkin)

Subject: Re: Correction for Star in M57

Jason Ware (jtws@dalsol.rtc.sc.ti.com) wrote:

Central stars of planetary nebulas put out a lot of energy in the ultraviolet. It could be that some people are more sensative to this. One class of people who can see UV better are people with artificial lenses due to cateract surgery. Walter Scott Housten of "Deep Sky Wonders" fame commented about this several times a few years ago. He had such surgery, and could see some neby central stars only with one eye and not the other (natural vs. artificial lens). I don't recall him mentioning M57's central star in this respect. Age may be a factor in UV visibility as well. I seem to recall that as the eye ages, its lens blocks more UV. Any opthamologists out there want to comment on this?

Joe Larkin

http://nearnet.gnn.com/wic/ed.toc.html

Subject: Re: M57 central star (was: Correction for Star)

From: rperepol@worldtel.com ()

Newsgroups: sci.astro.amateur

Date: Tue, 15 Aug 1995 06:31:46 GMT

]>I've seen the central star in M-57 with Roy Norris's 25" Obsession while

]>using a 9mm Nagler. It was a very difficult object indeed and was not

]>"steady". However, persistance and averted vision did reveal it.

]I have logged the central star several times in my C-14, at 315x or 559x.

]I agree that it is a quite difficult object. I once had a look through

]the 36-inch Clark refractor at Lick on a public night, when M57 was the

]object being viewed, and I could not the central star then; the seeing

]was noticeably ratty at the time, though.

I have been trying to see this for the last few months. I thought I saw it form my dark site in my 13" F4.4 using a 7.5mm Plossl, but I might have been trying too hard and imagined it :-) What is the smallest apature used by anyone who has seen it?

From: darksky@shore.intercom.net

Newsgroups: sci.astro.amateur

Subject: Re: M57 central star (was: Correction for Star)

Date: 15 Aug 1995 15:26:41 GMT

] freeman@netcom.com (Jay Reynolds Freeman) wrote:

] I have been trying to see this for the last few months. I thought I

] saw it form my dark site in my 13" F4.4 using a 7.5mm Plossl, but I

] might have been trying too hard and imagined it :-)

]

] What is the smallest apature used by anyone who has seen it?

I would say to you that a 7.5mm with your scope is not sufficient magnification. Try barlow and back the eyepeice away from the barlow to increase the magnification as much as possible. Use averted vision looking 2x distance of diameter of ring away from center and follow, follow, follow. This is a seeing sensitive object and is always seen in my 20 but averted vision is needed 95% of time at least at this site. If I had more magnification than 555x, it might be easier. I once asked a member of the AAVSO if he thought the central star was variable and he sort of raised his eyebrows. He said that a hot blue star of the type that remains at planetary nebula stage is not a likely candidate for variability. I then suggested that if differences in magnitude have been noted, maybe it is a result of physical light blokage by nebular material within the spindle or 'hole' of the ring. There are cases of this (Hind's, Hubble's variable nebula) seen as a result of shadows cast upon nebula by intervening clouds of gas surrounding the light source star. Although these are different, maybe there could be a mechanism that causes variability even though the gas is so tenuous.

Russ

From: riku@miricom.fi (Riku Henrikson)

Newsgroups: sci.astro.amateur

Subject: Re: Correction for Star in M57

Date: 15 Aug 1995 13:01:23 GMT

I'll try to answer to all of you who corresponded earlier :-) First of all, I'll mail more pictures of this object (for example surface plots and intensity charts made at NOT) to newsgroup binaries.pictures.astro in case somebody can't Finnish Deep Sky Section's homepage at address http://www.sci.fi/~riku/deepsky/ (not getting it may be caused by limited accesses abroad or typo etc). Check out these new pictures too, some of them are extremely interesting like surface plot which clearly shows the 'star' get brighter gradually and not immediately as would happen if it would be foreground object. So this tells us the object is either behind M57 or inside it. The magnitude determined for it by Arto Oksanen at NOT-observatory is 16.2 in V.

The object is pretty darn difficult to see visually and it could be used as a test of a) observers skills and b) atmospheric conditions. I believe the more difficult than seeing it is believing you really see it... This is where you can separate experienced observer from beginner. O-III and UHC seem to enhance the view a bit. It's also easier to see with higher magnification. Sometimes when I haven't seen it easily I've shook the scope and it helps... Funny :-)

Regarding the central star and it's visibility. I first saw it steadily using 13 incher telescope at magnification 760x. To see this object you don't need big telescope nor perfect conditions but merely extremely high magnification. The other factor is that this is a variable star of very long term. It varies from 14.6 all the way to 15.5 and this of course makes it difficult to see... It's on Russian list of variable stars but for some reason nobody has really studied it to the best of my knowledgde. The color might be the other thing explaining why some- body sees it easily and others don't. But, in my opinion, the most important factor is experience of observer. Seeing something really is a skill and you definitely get better and better as years pass. I've had really fun with this feature in M57. And if I do get spectra for it it's really nice to know where it is exactly located and is it a star at all. Stay tuned, this is not yet over :-)

From: darksky@shore.intercom.net

Newsgroups: sci.astro.amateur

Subject: Re: Correction for Star in M57

Date: 15 Aug 1995 15:11:25 GMT

] riku@miricom.fi (Riku Henrikson) writes:

]

] The object is pretty darn difficult to see visually and it could be

] used as a test of a) observers skills and b) atmospheric conditions.

] I believe the more difficult than seeing it is believing you really

] see it... This is where you can separate experienced observer from

] beginner. O-III and UHC seem to enhance the view a bit. It's also

] easier to see with higher magnification. Sometimes when I haven't

] seen it easily I've shook the scope and it helps... Funny :-)

At 16.2 magnitude, yeh it should be difficult. As I stated earlier, a photo in Burnham's Celestial Handbook clearly shows this star in a blue light palomar photo.To me, seeing is seeing and thinking you might have seen it is not seeing, it's suspecting which is not worth much as an objective observation.Since I spent better than an hour two nights ago trying to see this star and could not despite being able to view the central star at 555x, let me report this: The brightening in the area of this star can be easily detected at lower powers and does appear as stellar at times. However, increased magnification yeilds no star so I would not call my view successful. If an o111 or uhc filter 'enhances' the view of this star, a very good chance is that the visual sightings in 'normal size' telescopes of this 16.2 magnitude object are sightings of the brighter 'knots' in the area IMHO.

] I've had really fun with this feature in M57. And if I do get spectra

] for it it's really nice to know where it is exactly located and is it

] a star at all. Stay tuned, this is not yet over :-)

What else would it be? Have you looked at the blue light photo (palomar)? It certainly appears as a stellar point.

Keep us posted,

Russ

[amastro]

I don't know about these galaxies - but I think they are anonymous ones. What I know is that IC1296, at the upper right corner of m57jac1.jpg is readily visible in a 30cm scope, and shows some details in a 45 cm Dobsonian. If these galaxies were visible, then some of the fine filaments of the outer halo of M57 would be also visible. Are there any visual observations of M57's outer halo?

Gaspar A. Bakos

------------------------------------------------------------------------

Gaspar,

The 152" diameter irregular inner halo of M 57 was observed by myslef, Brian, and a few others at TSP ' 96 with a 36-inch f/5 reflector under a very transparent sky. At powers of 415x and 508x, while using a UHC filter, the entire perimenter of the "ring" itself literally looked wooly! However, at ~1/2 the ring's diameter out from the edge of the bright disk was a very thin and filamentary strucuture that could be carefully followed around the entire perimeter of the nebula. When I first noted it, it appeared as if the ring nebula that we all know and love was nestled inside of this squarish shaped glow of faint and extended limb-brightened nebulosity. With the aid of Jacoby's photo, some very bizzarre structure could be spotted within the glow, however, the 222" detached outer halo remained elusive despite my efforts ;-)

Jay McNeil

[amastro] Anonymous galaxies near M57

Playing with a deep H_alpha image of the Ring Nebula (M57) kindly sent recently by George Jacoby, I found two faint galaxies near the planetary. Apparent also on the DSS image, they are not listed in NED nor SIMBAD. Since the planetary is one of the objects to be thoroughly discussed in my forthcoming book (along with interesting objects nearby), I wonder if someone knows more about these ghosts. A few years ago I would bet that nobody could see them, but now I know that YOU can see everything!

The Jacoby images (original FITS file edited by me) can be seen at

http://www.bm.cesnet.cz/~ondra/m57jac1.jpg

and

http://www.bm.cesnet.cz/~ondra/m57jac2.jpg (detail)

Please don't circulate or distribute them.

Clear skies,

Leos

------------------------------------------------------------------------

I don't know about these galaxies - but I think they are anonymous ones. What I know is that IC1296, at the upper right corner of m57jac1.jpg is readily visible in a 30cm scope, and shows some details in a 45 cm Dobsonian. If these galaxies were visible, then some of the fine filaments of the outer halo of M57 would be also visible. Are there any visual observations of M57's outer halo?

I remember spotting IC4677 close to NGC6543 - thanks to Leos, that was great fun. I also tried some of the faint galaxies at the edge of Helix, but I think the telescope wasn't big enough to spot them.

Clear skies, Gaspar

***********************************************************

Gaspar A. Bakos

Currently at Space Telescope Science Institute (bakos@stsci.edu)

3700 San Martin Drive, Baltimore, MD21218, USA

***********************************************************

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Gaspar Bakos wrote:

]If these galaxies were visible, then some of the fine filaments

]of the outer halo of M57 would be also visible.

Don't forget, however, that the galaxies have (presumably ;-) continuous spectrum and the image was taken in H_alpha, so they could be brighter visually that the comparison with the M57 halo suggests. At least their central parts.

Best,

Leos

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It's also interesting that while it's clear Larry Mitchell's been looking for anonymous galaxies near M57 with his giant telescope he failed to spot these two, although the photos suggest they might actually be brighter than the two galaxies he found nearby (MAC1853+3307 and MAC1854+3259, locations are hidden in designation :). One possible explanation could be that the size of these two objects are too small to be noticed without specifically looking for them.

When the nights here in Finland finally gets darker I'll definitely take it my mission to try to spot these two. Weather permitting I'll do it in our annual deep sky -meeting held in 10-11.10. There should be an 25" Obsession telescope as well as several in the range of 16-20" which I suspect would be enough to see these if one knows what to look for.

Lovely discovery Leos, keep up the good work!

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Riku Henriksson Email: riku@sgic.fi All that glitter is not gold

Pohjolankatu 28 c 37 GSM +358 50 3042977 All that wanders is not lost

33500 Tampere Puh +358 3 255 6819 http://www.sci.fi/~riku

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Waldee, S.R. (1997)

Observing Messier 57, the "Ring" Nebula

by S. Waldee

Like M-42 and M-17, the "Ring" planetary nebula is a sure showpiece for any telescope and star party in season. Visible even in light- polluted skies, or with a 3" or even smaller aperture scope under proper conditions, this object offers one of the most fascinating sights in the deep sky.

Described as "annular" for its ring- like shape, this planetary is a cloud of expanding gas, through which we see the relatively thick edges. Powerful instruments will show an overall milky glow, betraying the excited gas in the central region.

Though it is included in the Messier catalog of 'comet- like nebulous objects', the "Ring" was actually discovered by another Frenchman, Darquier, during the year 1779. Both Charles Messier and William Herschel believed that it might be possible to resolve M-57's dull patch into individual stars, but spectroscopic analysis reveals that the "Ring" consists of brightly- fluoresced doubly- ionized oxygen, radiating at a frequency of 495 to 501 nm, the bandpass center of the contrast- enhancing oxygen- III nebular line filter, currently available from two manufacturers: Lumicon in Livermore, and Thousand Oaks Optical in Thousand Oaks (both in California.) In addition, the standard narrow- band emission nebula filter, typified by the Lumicon "UHC" [tm] model, helps enhance views of the object in light- polluted skies.

The "Ring" is at least one astronomical object that was accurately seen, if not fully understood, during the heyday of 19th- century visual astronomy: Professor E. S. Holden, not always a reliable observer, produced a remarkably correct drawing before the advent of astrophotography. Decades later, the Mt. Wilson telescope revealed a hitherto- invisible faint and tenuous puffy outer shell, extending beyond the bright annulus that is seen with small telescopes (see page 1172 of Burnham's Celestial Handbook, Vol. Two, or click on deep CCD image on the Electronic Universe Project's Galaxy Gallery Page III.)

We recently received a note from the distinguished astronomer Brian Skiff of Lowell Observatory, who comments on current findings of the nature of the "Ring" nebula's gaseous shell:

"Do note that the Ring is indeed a torus; the old lore about it being a sphere is wrong. What a spherical shell looks like is something like NGC 6781, where there's a radial gradient in brightness, instead of the hard-edged annulus we see in M57 and other objects. Most planetaries are annular or bipolar to some degree, and very rarely are they spherical shells. An example of what M57 might look like if it were side-on to our line of light is M27, which is a fat annulus like a wide wedding band viewed from the side."

M-57's CENTRAL STAR:

The celebrated central star has been rated at a visual magnitude of 14 to 16: its detection by the eye is unpredictable, though it registers clearly on a well- exposed photograph.

Tyro observers who have read of the central star in the "Ring" may believe they have glimpsed it, but should be assured that it requires luck, clear seeing, patience, and a superb large- aperture instrument! The glowing gases that appear to fill the interior of the "Ring" -- likened by Sir John Herschel to fine gauze -- illuminate the region with nearly the same faint glow as the brightness of the central star, a strange, hot, bluish dwarf.

Under imperfect conditions, a contrast or irradiation effect may cause the interior glow of the "Ring" to appear to peak at a central point. When this is suspected, increase the telescope's magnification to the value recommended for achieving the stellar magnitude limit: about 1 power per millimeter of aperture. Generally, this spurious 'star' will disappear, but sometimes, by using averted vision with a large scope, the true star may be visible! Even an 8" aperture scope, however, will show at least one or two internal stars, if not the famous central one; Walter Scott Houston once perceived a fine "peppering" of stars therein.

The present author of this article spent many a year trying to spy the central star of the "Ring", but without success. In fact, after producing and recording the audio tape used as accompaniment to the video slide show at the "Shane" Telescope at UC/Lick Observatory's Mount Hamilton, the author and his colleague Rich Page were treated to a view of M-57 through the great 36" Clark Refractor. Page could immediately spot the central star; but this author had not yet fully dark- adapted his eyes, and failed once again to see it!

Finally, using a good- quality 17.5" f4.5 Dobsonian telescope owned by our colleague Dr. Douglas Hudgins, at a dark- sky site in central California, the central star was at last observed a few seasons back -- as well as recently -- though not without difficulty.

The interior of the "Ring" is filled with a bright milky nebulosity, in a view with a moderate- to large- aperture scope. The central star's light is not much greater in brilliance to the eye's view through a big telescope than the overall surface brightness of this gauzy sheen. Averted vision must be used, and the magnification must be high enough to increase the size of the star image, and increase the contrast, so that it stands out clearly: we suggest about 350 - 400x. In moments of calm seeing, then the star may be visible as it flickers in and out of detectability.

Dreyer Summary (NGC): Magnificent. Ring Nebula, Bright, Planetary Nebula, Considerably Extended, in Lyra.

The eyepiece sketch [above] made while viewing with our 8" f5.2 Newtonian (with reversed and inverted image) shows the Ring Nebula at fairly high magnification. Our observing notes for 6.06.97 recorded that" "the object was evident as a small speck (but not yet annular) at about 30 to 35x. Central star (which seems very slightly offcenter) was intermittently visible in 17.5" scope with about 400x, using averted vision; two other stars were visible inside the annulus. In both scopes, a 'scintillation' was detected of the outer gaseous shell of the nebula using high powers."

The uneven illumination of the ovoid annulus is evident in the drawing with the 8" scope, but not -- of course -- the faint central star. Due to the high surface- brightness of the object, the Ring is a beautiful sight even in a much smaller- aperture telescope. If you have not yet observed this wonderful object, be sure to do so while it is high in the night skies!

Contemporary observations

Chris Vermeulen

2006 September 23

2006/9/23, 20h20

Sky Conditions: Clear

Quality of Observation: Good

Rhino & Lion Nature Reserve (Observatory)

6" Dobsonian, 25mm & 10mm Eyepieces

Low on the horizon, the Ring Nebula was an amazing site to observe for the first time. At first a very feint ring-like object became visible between the stars of Lyre, then as if it jumps out to the foreground the Ring Nebula becomes very clear and the distinct ring shape is clearly visible with the void in the centre.

At 120x magnification it was amazing to see such splendour and be captivated by it's beauty as the object filled the field of view. The Ring Nebula was not as impressive seen at 48x magnification, but could still be identified very faintly.

Richard Ford

2010 ,July 3rd Saturday

Location:Perdeberg.

Time:11:30pm.

Telescope:12"-inch Dobsonian Reflector Telescope.

Eyepieces:9mm eyepiece.

7mm eyepiece.

Sky Conditions:The fainter parts of the milky way are barely visible.

Transparency of the Sky:Haziness only visible on the horizon.

Seeing:Atmosphere stable with little interference.

Object Name:Ring Nebula.

First Impression:Planetary Nebula.

Location:Lyra.

Chart Number:No.6(Extract taken out of "Atlas of the Night Sky").

Size:9mm Eyepiece:Field of View:15'/7=2.1'.

7mm Eyepiece:Field of View:15'/6.5=2.3'.

2.1'+ 2.3'=4.4'.

4.4'/2=2.2'.

Size in Arc Minutes:2.2'.

Ratio:1:3.

Major Axis:2.2'.

2.2'/3=0.7'.

Planetary Nebula is 2.2'*0.7'.

Brightness:Bright.

Brightness Profile:High Surface Brightness.

Challenge Rating:An awesome sight to observe this large planetary nebula under a very dark sky.

Description

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This large planetary nebula has an oval shape which looks like a smoke ring at 167*. At 214*,the Ring nebula's dougnut shape is seen at close range.At higher magnification this planetary nebula looks more oval in shape. This planetary nebula has a greenish cast of light which is hard to see.

Carol Botha

2010 - 08 - 09

Location:Kambro, Britstown

Time: 21:50

Telescope: 8" Dobsonian f5. Eyepiece 15mm. FOV- 45'

Sky conditions: Seeing 3/5

Actual dimensions: 2.5'x 2.5(Cartes Du Ciel)

Object description:

Planetary nebula in Lyra

At last Im looking at the Ring Nebula.

Quite bright and Id say slightly oval ring. Higher magnification to try and find a central star results in a wishy washy appearance. I could not see a central star.

Only a few stars surrounding the planetary a prominent line of evenly spaced stars towards the W.

At even distances from planetary, two stars, one SW, one NW. Im sure some will see this grouping as Jesus on the cross.

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