Object of the Week, June 27, 2021 - NGC 6894, PN G069.4-02.6 , PK 069-02 1 - CYGNUS

[Paul Alsing]

Object of the Week, June 27, 2021 - NGC 6894, PN G069.4-02.6 , PK 069-02 1 - CYGNUS

R.A.: 20h16m24.0s Dec.: +30°33'53"
Size: 44", Magnitude: 12.3

NGC 6894 is a planetary nebula in Cygnus, about 5,000 light-years from Earth, and is small to medium in both size and brightness. It is almost perfectly round and is annular, by which I mean it is a ring. When compared with M 57, NGC 6894 is about half the size and half the brightness, but it in any case a very nice object.

NGC 6894 was discovered by William Herschel on July 17th, 1784 (see Steve Gottlieb’s notes (https://www.astronomy-mall.com/Adventures.In.Deep.Space/NGC%206000%20-%206999%20(11-30-17).htm)for more detailed information).

While doing my due diligence on this object I came across a nice article by Phil Plait, here (https://www.syfy.com/syfywire/a-dying-stars-magnetic-racing-stripes), which talks about the interaction of NGC 6894 with the Interstellar Medium (ISM). This article also includes a link to the original paper (http://cdsads.u-strasbg.fr/pdf/1997MNRAS.289..665S). I found it to be a fascinating read. It also includes some spectacular photos of this very interesting object. I'm wondering if anyone has glimpsed those parallel clouds visually. I didn't know about them previously, but I'll take a look next time I'm out! You just never know what you might see, if you look!

There are several nice pictures of this guy on the internet, but none are as good as Adam Block’s…

4365

In my own 25” f/5 Obsession several years ago I had a great view while attending the Golden State Star Party in northern California. The annular aspect of the nebula was obvious but variable, and the dark center was prominent, and the NPB filter improved the view quite a bit. It was a pleasant surprise and I plan on revisiting this object sometime down the road.

As always, give it a go and let us know.

[Raul Leon]

Hi here's my observation from 9/26/2011: Ngc 6894 planetary nebula in Cygnus; magnitude: 12.5 ; size:44" ; fairly bright, round with dark central area, one side seems brighter ; no central star observed; UHC filter works well on it ; I used a 10mm Radian at 198x with my 14.5 Starstructure Dob f/4.34366

[wvreeven]

My observation from 09/20/2015 with my 20":

At 83x I already see a small ring. At 320x and 545x I see a large ring but no central star. There is a star superimposed on the ring. The ring itself is not uniformly lit but it has brighter and darker parts. Very nice!

[Don Pensack]

Paul,
A nice object. I have become so used to small planetaries that my notes recorded this as:
"moderately faint, in a very rich field of stars, large for a typical planetary, but a low surface brightness, oval, annular, irregular brightness around perimeter, best w/O3 filter at 203x in the 12.5"

[PeterN]

Here's my observation of NC 6894 as one of the planetaries included in the A.L. "Planetary Nebula" list that I completed.

4367

[Ivan Maly]

Very nice object. I have these notes from nine years ago, when I observed it with my old 16-inch without a filter at ~140x, to try to approximate Herschel's view. SQM 21.64. "Soft annulus like a smoke ring. Brighter on the NW side (about 1/4 of the circumference)."

[kisspeter]

I really like NGC 6894. I remember when I was looking for it for the first time with my old 4" Newtonian among the sea of stars. It was such a joy to find the faint little oval using a map very much not suited for small and faint planetaries in the Milky Way.

Several years later I drew it with a 16". It's a beautiful ring of smoke with a star superimposed on the ring.
16", 220x, 2013.
43684369

[Clear Skies]

Observed this pretty one in October 2017 from the French Ardennes. 14" SCT @ 237x / 21':

Faint and quite large, without AV a round glow but the ring shape can not be discerned. With AV the ring shape is immediately obvious. The nebula is subtly wider and brighter on the NNW side. On the NNW edge is a mag. 14.5 star (4UCAC603-109752).

UHC Filter: When using this filter the ring shape is clear without use of AV.

OIII Filter: When using this filter the ring shape is slightly less clear compared to the UHC filter but is is clear that the nebula is wider and brighter on the NNW edge, the nebula is thinnest on the ENE side and wider again on the SE side.

Rated it 7/10.

4370 4371 4372

Click here (https://clearskies.eu/csog/downloads/dsfootw#21-26) for the observing guide.

[Uwe Glahn]

The red ISM clouds seems to be worth a visit.

I tried the faint halo but had no success. From my halo-project (http://www.deepsky-visuell.de/Projekte/Halo.htm) I copy my short notes: 27", 293x, [OIII], fst 7m0+
bright core somewhat fringed to the SW but no second shell or round glow around the core; negative observation

My old 16-inch showed a somewhat mottled ring structure with a faint star inside.

sketch: 16", 450x, [OIII], NELM 7m0+
4378
home (http://www.deepsky-visuell.de/Zeichnungen/NGC6894.htm)

[PeterN]

I made another observation and sketch of 6894 two night's ago using much higher power since the sky's seeing and transparency quality was better, <1.0 arc-sec.

4379

[Howard B]

I found an observation from 2005 with the 28-inch:

"6874 is much brighter than Abell 78 (my prior observation) but otherwise they look quite similar. No central star is seen but there is a faint star seen through/in front of the annulus. An enjoyable view, best at 467x without a filter."

4380 4381

[Uwe Glahn]

I just tried the faint ISM extensions and had success. Under good transparency and NELM 6m5+ skies, I tried several filters and an EP of around 4mm. Nothing was visible without filters and with the Hß. First idea of a somewhat brighter western side was given with the [OIII] filter. The brightening was much better visible with UHC and forms a triangle. All in all it was a tough object but not as hard as I thought.

sketch: 27", 172x, UHC, NELM 6m5+
4424
home (http://www.deepsky-visuell.de/Zeichnungen/NGC6894_ISM.htm)