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General Astronomy >> General Observing and Astronomy

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2orthern2ights
journeyman


Reged: 10/13/13

M57 central star? new
      #6135131 - 10/13/13 02:21 PM

Does anyone have a picture that points out the central star in the ring. I've read alot about people seeing it on the web but no where can I find directions on how to locate it. The general concensus on the star that is brighter in the center of the ring is that; that is not the star, but a star closer to us in a chance alignment to appear as if it was the central star. Where could the real central star be?

I have read all the pages about amature observations and seeing requirements, etc, etc,. But, at the moment, I can't find it because I have no idea where it is... Quite honestly I'm not gonna hold my breath. It is soo close to the limiting magnitude of my 14" that I doubt I would notice it. Never mind that it is set against a glowing nebula. But a photo should show it. Is it not in this photo?

http://imgsrc.hubblesite.org/hu/db/images/hs-2013-13-a-print.jpg

Im assuming that the central star, for the majority of people that peer through a telescope eyepiece, is the bright star in the center of the ring. This summer an amature astronomer, at my 14" telescope, said he witnessed the central star. To his defence, it appears dead center of the ring, it's pretty dim, nowhere can you find somthing to say otherwise... I guess I have seen it too. *reaches for belt notching tool*

Edited by 2orthern2ights (10/13/13 02:22 PM)


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SUN RA KAT
super member


Reged: 09/10/11

Loc: Centerville, Ohio USA
Re: M57 central star? new [Re: 2orthern2ights]
      #6135261 - 10/13/13 03:34 PM Attachment (56 downloads)

20 second exposure a few nights ago with my C14 with a Lumicon Giant EZ Guider with reducer lens and Nikon D800 @ ISO 1600. System should be around F7. Unguided.

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brentwood
Carpal Tunnel
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Reged: 11/04/05

Loc: BC Canada
Re: M57 central star? new [Re: SUN RA KAT]
      #6135309 - 10/13/13 04:04 PM

If it makes you feel better, I have looked at the Ring with a 72" (yes really) for 10-15 secs, and could NOT see the central star!

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northernontario
Pooh-Bah
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Reged: 07/01/09

Loc: Porcupine, Ontario Canada
Re: M57 central star? new [Re: brentwood]
      #6135315 - 10/13/13 04:07 PM

I too, with my 16 inch from a reasonably dark yard, have never seen it either.

But

The rest of sure does look nice.

Were you able to see any color with the 72 inch Brentwood?

jake


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brianb11213
Postmaster
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Reged: 02/25/09

Loc: 55.215N 6.554W
Re: M57 central star? new [Re: brentwood]
      #6135402 - 10/13/13 05:00 PM

Quote:

If it makes you feel better, I have looked at the Ring with a 72" (yes really) for 10-15 secs, and could NOT see the central star!



To see really faint objects requires (a) a MINIMUM of AT LEAST ONE HOUR's dark adaptation in a completely dark environment, (b) experience of how to use averted vision effectively, (c) object near the zenith in a dark, transparent sky, (d) a magnification of about 20x per inch of aperture to dilute the sky background and (e) seeing sufficiently steady to support that magnification.

Given most of that I've been able to see stars down to mag. 16.2 with my 11" SCT - but if I looked for 10 sec only I don't think I'd get within a magnitude of that. It takes ~10 minutes observing to get sufficient intermittent glimpses with averted vision to spot an object at the limit of vision.

So the central star of M57 catalogued at mag. 14.7 should be an easy object for me, right? No, it isn't. The "bright" background of the nebula makes it very difficult indeed ... perhaps more magnification might help ... I find the mag. 13 star just outside the ring to be really easy with 11" and can see it fairly easily with 4.3". My suspicion is that the magnitude of the central star is catalogued incorrectly.


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azure1961p
Postmaster
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Reged: 01/17/09

Loc: USA
Re: M57 central star? new [Re: brianb11213]
      #6135622 - 10/13/13 06:53 PM

I agree with Brian though a lot of folks who've found success tend to seem to go around 40x per inch. I'm not in that camp Ive still not seen it. I will say too, 10-15 seconds isn't nearly long enough for a threshold magnitude. On the faintest things Ive blown a whole half hour to confirm a sighting. If I had the ten second rule - I'd probably lose a full magnitude off my best effort.

By the way the central star - is - well - in the center. Really.
Pete

Edited by azure1961p (10/13/13 06:56 PM)


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pstarr
Carpal Tunnel
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Reged: 09/17/04

Loc: NE Ohio
Re: M57 central star? new [Re: 2orthern2ights]
      #6135631 - 10/13/13 06:58 PM Attachment (40 downloads)

Here is a magnitude chart of surrounding stars. If you can't see some of these, you won't see the center star.

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brentwood
Carpal Tunnel
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Reged: 11/04/05

Loc: BC Canada
Re: M57 central star? new [Re: pstarr]
      #6135688 - 10/13/13 07:32 PM

When I looked through the 72" (DAO, Victoria BC) I was dark adapted as much as I would have been at home. I am also familiar with using averted vision. I think it as others have said, 10-15 seconds is simply not enough time. When you are in a long line of people, most of whom look for 2-3 seconds, and say, "That's nice", that was about as long as I dared!
BTW, as I would never ask "What magnification is this", the Ring itself was about as big as an oval made with your fingers in front of your face!


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jgraham
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Reged: 12/02/04

Loc: Miami Valley Astronomical Soci...
Re: M57 central star? new [Re: brentwood]
      #6135696 - 10/13/13 07:38 PM

There was a long discussion of this in the deep sky observing forum. My take-away was that this is not easy. I have tried many times to glimpse the central star with my 16" and 16.5" scopes and at best I can say possibly maybe, but not for sure. Interestingly, my impression is that it is the nebula obscuring the star that makes it tough. If nothing else, it is a fun challenge.

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azure1961p
Postmaster
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Reged: 01/17/09

Loc: USA
Re: M57 central star? new [Re: jgraham]
      #6135722 - 10/13/13 07:52 PM

Folks who've seen it weigh big on the need to have great seeing - no doubt the reason the 72" didn't budge. Had the diffraction pattern been defined itd been easy as pie. But such is the smearing effect .

Pete


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kfiscus
Carpal Tunnel
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Reged: 07/09/12

Loc: Albert Lea, MN, USA
Re: M57 central star? new [Re: azure1961p]
      #6135808 - 10/13/13 08:46 PM

My observing buddy and I have seen it several times with our Z12s. The seeing has to be very good and you have to use very high magnifications. We never try unless Lyra is near the meridian. This is made much easier with an EQ platform.

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Feidb
Carpal Tunnel


Reged: 10/09/09

Loc: Nevada
Re: M57 central star? new [Re: kfiscus]
      #6135928 - 10/13/13 10:02 PM

The central star is an extreme challenge for most nights and apertures. The problem is not only the very dim magnitude (15.7), but the lack of contrast against the brightness of the nebula.

I've seen it twice, once with my home-built 16-inch f/6.4 in the mid-90's and once with my 16-inch f/4.5 commercial scope a few years ago. The conditions were pristine and I caught it just right. It took 300+ magnification both tries. The transparency and seeing were superb.

The thing is that there are some people with super eyes and perfect conditions (both optical and weather) that have caught it in as small as 8-inch scopes, or so I've heard. Yet as one of you pointed out, it can be invisible in a 72-inch.

Dimness and contrast against the nebula. Tough to almost holy grail. The visual mag. of 15.7 which is theoretically beyond the reach of an 8-inch scope? I can't say. I've heard of someone with a 12-inch that sees it quite often.


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2orthern2ights
journeyman


Reged: 10/13/13

Re: M57 central star? [Re: Feidb]
      #6136184 - 10/14/13 01:17 AM

ok... thanks a lot to everyone for weighing in on this one. We still got a problem. No map to the whereabouts of this terrestrial sized 15th magnitude white dwarf that shines in uv and blue. Tomorrow when I get back home I'll look into this. If you got time to look into this that'd be awsome. There are still mysteries in one of the most popular objects on anyones list! Amazing!

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Illinois
Carpal Tunnel


Reged: 12/18/06

Loc: near Dixon, Illinois USA
Re: M57 central star? new [Re: 2orthern2ights]
      #6136424 - 10/14/13 08:35 AM

I looked at M57 many times on my 16 inch dobsonian and I never see a central star. Maybe very crystal clear and very dark sky at high power!

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Achernar
Postmaster
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Reged: 02/25/06

Loc: Mobile, Alabama, USA
Re: M57 central star? new [Re: 2orthern2ights]
      #6137114 - 10/14/13 02:00 PM

I have never seen it, even through my 15-inch because the seeing in general is just not good enough for that. A faint star embedded in nebulosity is a tough nut to crack, I have noted how poor seeing hides the central stars of the planetary nebulae NGC-7662, NGC-6543 and NGC-7009 whereas during good seeing I can see them without too much trouble with my 10-inch. I have tried magnifications as high as 572X on the Ring Nebula without success looking for its central star.

Taras


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payner
scholastic sledgehammer
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Reged: 03/22/07

Loc: Bluegrass Region, Kentucky
Re: M57 central star? new [Re: Achernar]
      #6137217 - 10/14/13 02:48 PM

I have seen the central star through my C-14 (has since gone to a new home ). Seeing was excellent on those times of viewing it, near a 5/5. Unforgettable once you see it.
Best,
Randy


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hbanich
Pooh-Bah
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Reged: 06/17/05

Loc: Portland, Oregon
Re: M57 central star? new [Re: 2orthern2ights]
      #6137333 - 10/14/13 03:58 PM Attachment (11 downloads)

Quote:

ok... thanks a lot to everyone for weighing in on this one. We still got a problem. No map to the whereabouts of this terrestrial sized 15th magnitude white dwarf that shines in uv and blue. Tomorrow when I get back home I'll look into this. If you got time to look into this that'd be awsome. There are still mysteries in one of the most popular objects on anyones list! Amazing!




The central star really is the one in the middle -


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dpwoos
Pooh-Bah
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Reged: 10/18/06

Loc: United States
Re: M57 central star? new [Re: hbanich]
      #6137921 - 10/14/13 09:46 PM

I am skeptical of most claims. The only reported observation that I 100% accept is by my older son, who observed it in a 60" scope on Mt. Lemmon. He says that it was not super easy to see. Of course, my skepticism doesn't make other claimed sightings false, and everybody decides for themselves who and what to accept, and with what degree of certainty. I do know that it is very easy to see what you want to see, especially if you know the exact location of the target.

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kfiscus
Carpal Tunnel
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Reged: 07/09/12

Loc: Albert Lea, MN, USA
Re: M57 central star? new [Re: dpwoos]
      #6138016 - 10/14/13 10:47 PM

To twist your words (but hopefully not your tail) I wanted to see it and it wasn't easy. It took the convergence of very good seeing, a collimated and cooled 12", smooth tracking, and high magnification. The star would show itself for 1/2 a second or so. The central star was easier while out at the Nebraska Star Party and its DARK skies.

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David Knisely
Postmaster
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Reged: 04/19/04

Loc: southeastern Nebraska
Re: M57 central star? new [Re: brianb11213]
      #6138269 - 10/15/13 02:23 AM

brianb11213 wrote:

Quote:

So the central star of M57 catalogued at mag. 14.7 should be an easy object for me, right? No, it isn't. The "bright" background of the nebula makes it very difficult indeed ... perhaps more magnification might help ... I find the mag. 13 star just outside the ring to be really easy with 11" and can see it fairly easily with 4.3". My suspicion is that the magnitude of the central star is catalogued incorrectly.




According to Brian Skiff of Lowell Observatory, with professional photometry of the central star, all published photometric measurements report the central star's visual magnitude at about 15.0 or perhaps one to three tenths fainter, and with no demonstrated evidence of variability. The smallest telescope I have managed to see the central star in is a 9.25 inch SCT (480x), which was also just barely showing stars down to 15.3 in the area around M57. This would tend to support the figure of magnitude 15 for the central star. Clear skies to you.


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