Object of the Week, September 19, 2021 - NGC 7354

Object of the Week, September 19, 2021 - NGC 7354 = PN 107.8+02.3 = PK 107+2.1 - Cepheus
R.A.: 22h40m19.9s
Dec.: +61°17'08"

Size: 22", Magnitude: 12.9

NGC 7354 is an often overlooked planetary nebula in Cepheus, and in September it is pretty much available all night for observers in the northern hemisphere, culminating tonight about an hour before midnight. This object was discovered by William Herschel on November 3, 1787. Dreyer described it as, "a planetary nebula, bright, small, round, pretty gradually a very little brighter middle". This 2010 paper…

https://arxiv.org/abs/1002.0881

… tells us that “…NGC 7354 has four main structures: a quite round outer shell and an elliptical inner shell, a collection of low-excitation bright knots roughly concentrated on the equatorial region of the nebula, and two symmetrical jet-like features, not aligned either with the shells' axes, or with each other…”, but I can tell you that in my 25” F/5 Obsession I saw a fairly small, fairly bright grayish disk that was a little annular and maybe a little oval in shape, with a subtle brightening of the rim in a couple of spots. I looked for but did not detect the central star. A lot of the pictures show a decidedly blue or green cast to this planetary nebula but all I saw was gray.

There are lots of astrophotos of this fellow…

https://tinyurl.com/stuh66m8

… but of course, the Hubble shot takes the prize…

Attachment 4453

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

Hi here's my observation from 10/11/2007: Ngc 7354 is a planetary nebula in Cepheus : magnitude: 12.9 ; size: 22" ; ovalish, slightly brighter on one side ; no central star observed; I used a 8mm Ethos at 238X with my 14.5 Starstructure Dob f/4.3 Attachment 4454

Hello all,

only 1 entry in my observing logbook, when testing the new-to-me Baader Classic Orthos:
10th August 2016: 6" F/5 achro, BCO 10mm and 6mm, Astrodon OIII 5nm filter blinked against H-Beta.
Small disc, no details seen and also not expected to be seen.

I can remember having tried this PN with my old 25x100 FB binoculars, but without filters it has not been certain.

Clear skies,
Jiri

With my 20" from a fairly light polluted area in October 2014, I noted that this nebula responds well to an OIII filter and handles a magnification of 366x well. No details seen apart from a round glow and two stars at en edge, one of which is brighter than the other.

At 435x in my 18", I noted signs of annularity (or at least an enhanced rim): "appears slightly brighter along portions of the rim, particularly along the SE side."

Through my 24" at 375x, the PN seemed slightly elongated SW-NE, ~25"x20". And there was more structure to the rim: it was brighter along the SE side and very slightly brighter along the NW or W side. The NE quadrant of the rim was weaker. At 500x, NGC 7354 clearly had a mottled appearance with what appeared to be several very small brighter spots that winked in and out. Several stars are very near including a mag 14 star 0.5' SW, a mag 14-14.5 star 0.8' W and a mag 15 star 0.7' NW. I didn't see the central star either.

Very nice object. I have this from 2014, club site, my old 16", 140x.

Pretty bright, round. Even brightness. Well-defined edges. Star immediately to the SSW. A fainter star is slightly farther W.

My latest observation is from 1994 (!) with my old 20-inch:

Nice, round planetary in Cepheus. Has a rough, bumpy appearance and is surrounded by 3 faint field stars. Seeing has improved, 605x!"

Definitely time for another look...

Got two sketches here.

sketch: 16", 450x, no filter, NELM 6m5+
Attachment 4461
home

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sketch: 27", 837x, no filter, NELM 7m0+, Seeing II
Attachment 4462
home

My notes might be wrong, but I recorded this in 32cm in 2007 at 493x as being oval, large, and fairly bright for a planetary,
and I noted that a central star was seen. No filter. Skies were ~21.6 mpsas. Altitude 8350'. Transparency and seeing better than average.
Was it impossible for me to have seen the central star? You guys make me doubt my notes.
Outside of a nebula, I have no trouble seeing a mag. 16.1 star with direct vision, and I've seen fainter central stars than that in other nebulae.

Quote:

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Originally Posted by Don Pensack

My notes might be wrong, but I recorded this in 32cm in 2007 at 493x as being oval, large, and fairly bright for a planetary,
and I noted that a central star was seen. No filter. Skies were ~21.6 mpsas. Altitude 8350'. Transparency and seeing better than average.
Was it impossible for me to have seen the central star? You guys make me doubt my notes.
Outside of a nebula, I have no trouble seeing a mag. 16.1 star with direct vision, and I've seen fainter central stars than that in other nebulae.

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Hi Don... Well, all I can say is that this central star is at least 16th magnitude, and the central star of the famous Ring Nebula is listed as being mag 14.8 (although I suspect that it is closer to 15.8 myself), and this star is a real stinker to see except under ideal circumstances, and even then you need to wait for an elusive moment of great seeing to spot it... so I am not at all surprised that this central star is a difficult catch!

I can't honestly say that I see the central star in M57 (alternately listed at 15.1 or 15.2 but estimated by many to be more like 15.6) all the time, but I usually do see it 75% of the time.
Conditions of obscuration vary a lot. The central star of NGC 6905 is 15.5, but is an easy, direct vision, view 100% of the time.
I'm going to go back and look at this planetary again to confirm my earlier central star sighting.