NGC 6853
A Planetary Nebula in Vulpecula
| Magnitude: | 7.1 |
| Apparent size: | 8.0′ x 5.7′ |
| Diameter: | 3.2 light years |
| Distance: | 1,400 light years |
| Image date: | 2020-09-12 |
| Exposure: | 51 x 90sec = 76 minutes. |
| Field of View: | 38.7 x 25.7 arcmin. Up is 171 degrees E of N. |
One of the nicest looking planetary nebulae, M27 is also known as the Dumbbell Nebula or the Apple Core Nebula. It’s appearance is that of a prolate spheroid, a wonderful sounding term which basically means “shaped like the ball thrown around in sports like rugby or gridiron” – although why those sports refer to their squashed spheroids as a “ball” is a total mystery!
The oblateness is visible as the faint light blue coloured gas which fades away to the right and left of the object in this image.
The nebula is expanding at a rate of 2.3″ per century, so is barely noticable over a human lifetime – despite its expansion velocity of 31 kilometres per second.
The object is estimated to date back 9,800 years, when the gas was ejected from a dying sun-like star, leaving the stellar core remnant (clearly visible at the centre of the nebula) to fade as a white dwarf over trillions of years, until it becomes a black dwarf in the unimaginable far distant future.
Telescope Details
| SkyWatcher Esprit 120 mm apochromatic 3-element refractor; 840 mm f/l @ f/7. |
| Field flattener; ZWO Duo-band (H alpha & OIII) filter; 2x Powermate |
| SkyWatcher EQ6-R Pro mount; ZWO ASI120 guide camera. |
| Imaging camera: ZWO ASI 071 MC Pro (CMOS 28.4mm 16 Mpx). |
| Software: EQMOD, Cartes du Ciel, PHD2, SharpCap, Gimp. |
| Cosmic Focus Observatory location: 34° South. |
See annotated image at Astrometry.net
Cosmic Focus 
Some wildly swinging numbers in this post. 🙂
31 km/s – seems impossibly fast yet barely a fraction of the speed of light
9,800 years – all of known human history fits nicely into it, with room to spare
1 trillion years – unfathomable time span, considering that’s about 70 times the current age of the Universe. I know astrophysicists have their theories on what things will be like then and beyond. I’m guessing the fate of the Dumbbell Nebula will be long forgotten.
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A very good point. Astrophysicists have to deal with numbers that can be so immensely large (or for that matter even so ridiculously tiny) that we mere mortals feel overwhelmed with incomprehension.
To put the expansion rate of M27 into some sort of context, the New Horizons space mission is hurtling through the Kuiper Belt at half that speed – just 16 km/s.
🙃
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Wow, that’s fast, err, I mean, slow. It’s all relative.
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I like the name Apple Core.
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I like it too. I think the name matches the appearance – but I don’t know anyone who actually uses that name. We all call it the Dumbbell down here, I just see Apple Core in online references, so some folks must use it.
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Today, Venus passes very close to Regulus. I wondered if I could see them both in daylight. I set up the scope at 10 am and easily found Venus in the blue sky. But had no luck finding Regulus. This person got them both just at sunrise. https://spaceweathergallery.com/indiv_upload.php?upload_id=168466
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Not bad, considering Regulus is roughly a hundredth of the brightness of Venus.
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How about that?! . . . a celestial object named after a politician . . . but which one?
Nice capture, as always.
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I could name a few, in my country and yours.
🙃
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Beautiful image! It’s fascinating how there’s a strong reddish arc on the (relative) top and bottom with a fainter bluish glow between. I wonder if it’s the composition that creates the different colors and textures or if it has something to do with the motion.
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