Object of the Week August 7th, 2016 - NGC 6951 also known as NGC6952

[Dragan]

NGC6951
NGC6952
UGC11604

Cepheus

Galaxy

RA 20 37 14.1
DEC 66 06 20

Mag: 11th

Size: 3.9' x 3.2'

Class: SAB(rs)bc

NGC6952 was discovered at the Marseilles Observatory by French astronomer Jerome Coggia in 1877. Lewis Swift, independently discovered this same galaxy using the 16" refractor of Warner Observatory 8 years later on September 14th, 1885. John Dreyer catalogued Swifts object as NGC6951, ignorant of Coggias previous entry of NGC6952 and subsequent positional error of nearly 20 minutes. Upon the finding of Coggias error, NGC6952 was dropped and Dreyer made the proper designation correction in his Index Catalogue.

Visually, NGC6951 is a fairly large barred spiral located 70Mly away in the northern constellation of Cepheus, thereby making it a circumpolar object for many northern latitude observers. Located near the plane of our own Milky Way, NGC6951 can be a bit difficult to eek any real detail out of. A rather large but low surface brightness object, NGC6951 has a bright stellar nucleus with a bar extending W-E apparent in larger telescopes. The beautiful spiral structure, as seen in pictures, can be quite elusive. Dark conditions and larger scopes are needed to see the brighter eastern arm that wraps nicely around the galaxy.

Another factor that may possibly play a part in limiting finer visible details is the IFN. The Integrated Flux Nebula, or IFN is a structure of dust and gas that lies in intergalactic space just outside of our own Milky Galaxy. Not unlike Zodiacal Light which is reflected sunlight off of particulate in our own solar system, the IFN reflects the combined starlight of our own galaxy. NGC6951 lies in the direction of some very dense regions of the IFN. So it is possible that between its position near the plane of our own galaxy as well as in the direction of our IFN, finer details of NGC6951 may always be a challenge to us visual observers. (this is strictly my own theory of course)

So what observations have you had? Were you able to see the arms of this beauty? In what size scope?

And as always,

"Give it a go and let us now!"

2217
©Cam and Connie Baher/Adam Block/NOAO/AURA/NSF


2218
NGC6951 and a very apparent IFN
©Bob Franke


2219
©NOAO

[Uwe Glahn]

Nice and relatively unknown galaxy Dragan. I want to add the nuclear ring detail, what should be visible in large telescopes when seeing is good enough.

I gave it a try 3 years ago, I noted: bright, large, difficult details; bright nucleus looks round and flat with stellar spot in its middle, no ring structure detectable; arms fain, brighter shells around the nucleus in E-W direction (27", 293x-419x, SIII, Nelm 6m5+)

[wvreeven]

No way to see the ring with my 20" then...

[Steve Gottlieb]

Here are my last two observations of this interesting galaxy --

24" (7/23/14, Lassen National Park, 8200'): fairly bright, fairly large, slightly elongated, ~2' diameter. Sharply concentrated with a small, very bright core. A fairly broad "bar" extends east-west through the central region. Weak spiral structure is definite with careful viewing. An eastern arm appears as a subtle arc curving counterclockwise and passing west and then south of a mag 12.7 star 1.4' east of center. I expected the western arm to be more obvious, but it was only visible as a slightly brighter curving "edge" of the outer halo from west to north.

48" (10/23/14, Lowrey Observatory, Fort Davis): large spiral with a brighter central region extending ~1.8'x1.2' ~E-W and the outer spiral arms increasing the dimensions to 2.8'x2.0', with the arms reaching north and south. Well concentrated with an intensely bright, circular core that is embedded with a bright, elongated oval "bar" extending E-W. A fairly narrow spiral arm is attached at the west end of the central region and curves strongly counterclockwise to the north, passing between two mag 15.8 stars 1.3' WNW and 0.8' NW of center. This fairly low surface brightness arm is widely detached from the glow of the central region as it curls to the east, ending about 1.5' NNE of center. On the east side of the elongated core region a faint, shorter spiral arm curves south, passing near 3 or 4 faint stars oriented N-S and fades out ~1' SSW of center.