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Any visual impressions of NGC 1491 in Perseus?

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#1 George N

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Posted 17 November 2012 - 04:24 PM

I found lots of pictures on the ‘net, but only one visual description , with a 20-inch Dob and no filters.

Last night I could see it as a little triangle of haze using a 26mm Nagler in my 5-inch ES127ED triplet, using a UHC filter. However, I discovered a little later that the lens was starting to frost up.

There are several nice open clusters in the same area, plus the “not a planetary” PK 151+2.1, which seems to be another HII knot. I need to take a look at that one too!

#2 George N

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Posted 17 November 2012 - 04:37 PM

...found this in the Sketching forum: web page

#3 GlennLeDrew

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Posted 17 November 2012 - 06:30 PM

I've managed to glimpse it in 14X70 binos, sans filters.

#4 eps0mu0

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Posted 17 November 2012 - 09:38 PM

There is a description of 1491 in Sue French's "Deep Sky Wonders". She states the nebula is "fairly bright" in a 4" refractor at 47x. The view is improved with a narrow band filter. Check out her book for more details.

#5 David Knisely

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Posted 18 November 2012 - 01:16 AM

I found lots of pictures on the ‘net, but only one visual description , with a 20-inch Dob and no filters.

Last night I could see it as a little triangle of haze using a 26mm Nagler in my 5-inch ES127ED triplet, using a UHC filter. However, I discovered a little later that the lens was starting to frost up.

There are several nice open clusters in the same area, plus the “not a planetary” PK 151+2.1, which seems to be another HII knot. I need to take a look at that one too!


It is an odd-ball object that seems to be best seen in a narrow-band nebula filter like the DGM Optics NPB. I have seen in my 9.25 inch SCT without a lot of trouble, and my descriptions of it in that scope don't differ a lot with what I saw in my 14 inch f/4.6 Newtonian last winter. My log entry reads:

12/24/2011 at 0140 UT: 14 inch f/4.6 with NPB Filter "(52x) Oval area of nebulosity, small to moderate in size with brighter elongated core. 135x shows interior detail with bar-like main section 3' arc long oriented N-S and a fainter flaring on the south end that flows east. 11th magn. star located just off eastern edge of main bar."

Clear skies to you.

#6 George N

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Posted 21 November 2012 - 08:51 PM

Thanks guys! I'll have to look this one up again with either my 20" Dob or Kopernik Obs's 20RC. Maybe I can get an image? Anyway, it was new to me and now I'll have to return. From the descriptions I'm sure that I was able to see it in the 127mm refractor and the UHC filter helped.

#7 Starman1

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Posted 24 November 2012 - 04:26 PM

Using a 6" f/5 in 1993:
"bright, looks like miniature LMC, slightly triangular shape, large"
Not particularly detailed, but hey, it was a 6". From a Blue LP Zone.

#8 sgottlieb

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Posted 26 November 2012 - 03:07 AM

Here are five observations I've made since 1980:

18" (1/20/07): at 115x and 174x and OIII filter appears as a bright, large, elongated HII region on the west side of an 11th magnitude star. Appears roughly 4'x2', extending SSW to NNE and brighter on the south end. The west side has a fairly hard, well-defined edge while the east side is more irregular and fades into the background. Four faint stars are involved on the northern end and a pair of fainter stars are at the south end.

17.5" (3/2/02): at 100x, this is a moderately bright, roundish glow, ~3' diameter.  Extends mostly west of a mag 11 star, wrapping around the star, particularly on the north side.  Excellent contrast gain with an OIII filter as it appears bright with an irregular surface brightness.  There is a subtle bite cut out of the nebulosity on the east side that creates a darker hollow extending just west of the star.  At 220x (unfiltered), about a half dozen stars are involved or at the edges.  The nebulosity is quite irregular with a high surface brightness region preceding the star.  Faint, elongated haze extends from this patch to the NE past the star giving an elongated appearance.  A pair of mag 13-14 stars is at the northern end and another pair is just off the western edge.

17.5" (12/8/90): at 140x with OIII filter appears as a bright, moderately large, circular nebulosity involving a mag 11 star. The brightest portion lies to the west of the star and is elongated 3:2 ~N-S. There appears be a dark gap just west of the mag 11 star. Two very faint stars are superimposed near the edges.

13" (1/18/85): bright emission nebula just west of a mag 10.5 star, extends SW-NE, interesting shape.

8" (11/14/80): bright, large, ~6' diameter. A mag 10.5 star is at the east side.

#9 IVM

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Posted 18 March 2013 - 02:27 PM

Yes this thread was going cold, but I was just going through my observing notes from December and remembered reading it not long before that outing. A most curious object indeed. This is what I recorded when observing with my 16" from Cherry Springs:

NGC 1491. I.258. Not in Herschel 400, Caldwell, or HT. [It is O’Meara’s Secret Deep #14.] EN [emission nebula], mag. 11, central part 5’, faint outer parts photographically 20’. DSS looks like a small M42. At 45x it is a round diffuse patch, on the E side of which is a star. 225x does not change the dimensions of the nebulosity appreciably. The star is now on its E edge and the W side is brightest. The bright part extends around the star to the N but there is little nebulosity to the S. There seem to be some threshold stars involved in the brightest patch. OIII filter improves the contrast with the background dramatically but does not alter the shape or extent of the nebulosity. However, the W and NW edge now appears relatively sharp. The nebulosity concentrates toward this edge, the center of whose curvature roughly coincides with the star. It is therefore evocative of a glowing front of a stellar wind. [O’Meara confirms that this is more or less correct.]

#10 azure1961p

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Posted 18 March 2013 - 08:23 PM

Using a 6" f/5 in 1993:
"bright, looks like miniature LMC, slightly triangular shape, large"
Not particularly detailed, but hey, it was a 6". From a Blue LP Zone.


A year later i saw the same with my 8". Ive gone back from time to time a little bothered that it is so apparently structure less but easy enough to see.

Pete






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