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Thor's Helmet

NGC 2359, NGC 2361, Ced 94b, Gum 4, LBN 1041, RCW 5, Sh 2-298, Duck Nebula, Thor's Helmet, V 21, h 3075, GC 1511

RA: 07h 18m 23.8s
Dec: −13° 12′ 34″

Con: Canis Major
Ch: MSA:297, U2:274, SA:12

Ref: SIMBAD

(reference key)

Type: bright nebula (HII region)

Mag: B=?, V=?

Size: ?
PA: ?

Image gallery

Photos  (1)

Select a photo and click the button to view

History and Accurate Positions for the NGC/IC Objects (Corwin 2004)

NGC 2359. See NGC 2361.

Historical observations

William Herschel (c.1784)

Synonyms: H V-021

Discovered in 1785 by William Herschel with an 18.7-inch f/13 speculum telescope. He called it "a broad extended nebulosity. Forms a parallelogram with a ray southwards; the parallelogram 8' long, 6' broad, vF." In the Philosophical Transactions, 1811, Herschel classified it as a "detached nebulosity" describing it as a "broad faint nebulosity extended in the form of a parallelogram with a short ray from the preceding corner towards the south. The nebulosity is nearly of an equal brightness throughout the parallelogram, which is about 8' long and 5' or 6' broad, but ill defined."

John Herschel (1847) Cape Observations

Observed by Sir John Herschel at the Cape of Good Hope with an 18-inch f/13 speculum telescope. He recorded it as "a very singular nebula, much like the profile of a bust, (head, neck and shoulders,) or a silhouette portrait, very large, pretty well defined, light nearly uniform, about 12' diameter. In a crowded field of milky way stars, many of which are projected on it."

Lassell, W. (1866)

Bibcode: [1866MmRAS..36....1L]

Sketched and described.

Published comments

Helwan Obs. Bulletin No 22 (1921)

vF, 8'x5'. E 0deg approx; irr. nebula of the gaseous variety; shaped like the letter 'Q'.

Helwan Obs. Bulletin No 38 (1935)

Confrms HOB22.

Cederblad, S. (1946) [VII/231]

Ced 94b (NGC 2359)

Position (1900): RA 7 12.9, Dec - 13 2

Star: Anon (Mp=10.5:, V=11.0, SpT=Od)

Spectrum of nebula: emission spectrum (observed)

Classification: Neb associated with mainly one star (which may be multiple) - Fan-shaped object (eg. IC 59)

Size: 8'x6'

Notes: " 94 b = NGC 2359 = GC 1511 = h 3075 = H V 21. Disc. 1785. (114, 208, 216, 297, 304, 365, 550, 578, 630 Pl 37, 631). R. NGC 2361 is probably a part of this nebula."

Sharpless (1959)

A catalogue of H-II regions. Astrophys.J.Suppl.Ser., 4, 257-279.

Sh 2-298: "Contains peculiar ring structure; similar to No.162."

Lynds, B.T. (1962)

Lynds, B.T. (1962) Catalogue of dark nebulae. Astrophys.J.Suppl.Ser. 7, 1-52. [also: computer datafile: VII/7A]

Sulentic & Tifft (1973)

The RNGC (Sulentic and Tifft 1973) notes that this is a diffuse nebula.

Toala, J. A. et al. (2015)

"WISE morphological study of Wolf-Rayet nebulae" [2015arXiv150306878T]

WR 7: (RA, Dec J2000.0) [07h 18m 29.13s, −13 13' 01.5"]

Morphological classification: B = WR Bubble. (These nebulae present a thin shell or bubble both in optical and IR, mostly in the W4 band. Examples of these nebulae are those around WR 6 (S 308) and WR 16.)

Distance = 3.67 kpc.

Burnham's Celestial Handbook

Burnham calls this nebula very faint, very very large, 6' x 8' with curved filaments; central star is a Wolf-Rayet type of 11th magnitude.

Photo index

Photo Index by Jim Lucyk: Sky&Tel. 3/80 p195-197, Astronomy mag. 6/88 p11, 13, Vehrenberg's Atlas of Galactic Neb-1 p119, Sky&Tel. 6/88 p675.

Modern observations

Tom Lorenzin

Tom Lorenzin, in the electronic version of "1000+ The Amateur Astronomers' Field Guide to Deep Sky Observing", notes: "11M; 6' x 8' extent; shapeless blob with four 12M stars embedded in N portion; brighest patch is 10' S of stars; tails off to SW; N-filter helps with this emission nebula."

Hartung, E.J. (1968) Astron.Obj.South.Tel

Hartung calls it "a large rather faint even nebulosity in a fine field sown with stars, many of which shine through it. The rounded portion well defined north is about 6' across, with a long edge straight in pa 45 degrees about 9' long. 10.5cm shows the object faintly but more aperture is needed to see the form well."

Birkmann, Mark (IAAC)

Observer: Mark Birkmann; Your skills: Intermediate (some years); Date/time of observation: 01:00 UTC March 15; Location of site: New Haven, Missouri (Lat 38, Elev ~700'); Site classification: Rural; Sky darkness: 6 1-10 Scale (10 best); Seeing: 7 1-10 Seeing Scale (10 best); Moon presence: None - moon not in sky; Instrument: 30" f4 dob; Magnification: 76, 152; Filter(s): none, OIII, Hbeta; Object(s): NGC 2359/IC 468, Thor's Helmet or The Whistle; Category: Emission nebula

Description: Without a filter it was obvious how this object got the name the whistle. With the OIII filter the body of the whistle became the helmet and another protusion from the central area of nebulousity gave the appearance of a helmet with two horns on it such as is commonly seen in old viking movies. Below the helmet was some dimmer nebulousity which, with a little imagination, became a beard that outlined a dark central area (the face). To one side was an extended area of dim nebulousity which gave the appearance of long hair blowing in the wind. The view with the 20mm nagler was good but the object is fairly large and our best view was with the 40mm meade swf at 76x. With the Hbeta (inserted by accident) no nebulousity was visible. I first saw this object at WSP '98 through Jim Walker's 17.5" dob. This is a very impressive object and I am amazed that after 10 years of observing I was seeing it for the first time. It's good to know that no matter how long you have been observing there are always more great objects waiting to be seen!

Ware, Donald J

:"The Duck Head Nebula. This is a large and faint diffuse nebula which is best seen at low powers. It is about 10' in extent, and is composed of an arching segment intersected at almost right angles by a straighter component, resembling a duck's head and bill. I found it best seen with an Orion Ultrablock filter, while the Lumicon UHC filter did not do as well."

Mitsky, Dave (IAAC)

(e-mail: djm28@psu.edu); Instrument: 20-inch other Location: Mount Gretna, Pennsylvania, U.S.A.; Light pollution: light Transparency: excellent Seeing: excellent; Time: Mon Feb 10 02:25:00 1997 UT Obs. no.: 76

Using a friend's 20" f/10 classical Cassegrain and a 2" 40mm Orion MegaVista ocular I located and observed the unique diffuse nebula NGC 2359 (also known as Thor's Helmet or the Duck Nebula) for the first time from Pennsylvania. (I have seen it previously at the WSP.) It was barely visible without an O-III filter but when the filter was in place the nebula was unmistakable, resembling not so much a Viking's helmet as an M turned on its side.

AJ Crayon

AJ Crayon, using an 8" f/6 Newtonian, notes: "is a bright nebula also called the Duck Nebula. With a UHC filter it appears 12m 15'X15' at 100x. The neck is 15'x10' in position angle north with stars to the south, the beak 10'x15' position angle east and a 10m star marks the eye.

Steve Coe

Steve Coe, using a 17.5" f/4.5, notes: "Pretty bright, large, Irregular shape. Nebulosity extends out of the 30 minute field at 100X. UHC filter helps the contrast of this object a lot. I have always heard this object called the Duck Nebula because the shape includes a side view of a duck head with a bill. Sentinel 13" 7/10 -- 11X80 just barely seen, 100X pretty bright, large, irregular figure, "duck head" shape seen immediately without UHC filter, adding UHC make the field explode with nebulosity, many wisps cover the field from edge to edge. 220X + UHC lots of detail within Duck head, several dark areas and stars involved. 150X + UHC Best view, much neby around Duck Head and detail within, faint nebulosity to east, bright edge on north side."

Brian Skiff

& I 468

POSS: neb to E is real, oc Ha 6 ~20 E of main neb. * on S of faint neb =

SAO152707 (mv9.0, K0). mess of NGC/IC numbers here, all off-target:

I468, N2359, N2361 (which is closest to true position).

15cm - wkly vis in rich fld. BS, 6Nov1980, Anderson Mesa.

- pretty f haze, not really noticeable. BS, 26Jan1982, Anderson Mesa.

- easy lg neb @ 50x. not much change w/DS filt; def contrast improvement

w/UHC, which brings out diffuse glow sep on E side of main body by dk

lane. main neb rectangular w/long flat base on S, pointy appendage

extends W from this. line m12-13 *s across N edge in neb. SE corner has

rel br *. 7'x4' overall. 10' E is another rel br *: N of this is region

of apparent diffuse neb ~15'x10'. this persists w/ UHC, but 80x shows rel

dense bkgrnd of m13.5+ *s, so neb could be due to this. BS, 20Mar1988,

Anderson Mesa.

25cm - fairly lg, br, vis @ 50x. 10'x5' in extent, roughly rectangular w/broader

S base. no concen. in rich fld. BS, 6Nov1980, Anderson Mesa.

- br haze vis @ lox, elong N-S, 8'x4' in approx rectangular shape. 190x:

fntly gran. on S is m10.5 *. on N is X or triangle of six *s (five form

the triangle). BS, 26Jan1982, Anderson Mesa.

Contemporary observations

Magda Streicher

(no date)

Alldays (22.50S, 20.12E, 770m).

12-inch f/10 SCT (76x, 218x)

This time of the year affords an excellent time to look at the unique planetary nebula. The nebula is beautifully crescent shaped, and seems to have two "horns" on the NW edge, similar to a Japanese helmet. The flimsy nebulosity is show off a tender see through impression more so against the nebulosity towards SW. The brighter part of the nebulosity is towards north. The eastern end of the nebulosity is very hazy. The star field towards the west is dotted with faint field stars.

Richard Ford

2012 January 22nd, Sat

Location:Perdeberg.

Instrument:12-inch Dobsonian Reflector Telescope.

Sky Conditions:The fainter parts of the Milky Way are barely visible.

Transparency of the Sky:Haziness only visible on the horizon.

Seeing:Atmosphere stable with little interference.

NGC 2359

--------

Object Type:Nebula.

First Impression:This object looks like a medium sized cloud of gas and dust.

Location:Canis Major.

Time:10:20pm.

Chart Number:No.96(Extract taken out of "The Night Sky Observer's Guide" Volume One).

Size:26mm Eyepiece:Field Of View:57'/6=9.5'.

20mm Eyepiece:Field Of View:50'/5.5=9'.

9.5'+9'=18.5'.

18.5'/2=9.2'.

Size in Arc Minutes:9.2'.

Ratio:1:3.

Major Axis:9.2'.

9.2'/3=3'.

Minor Axis:3'.

Nebula is 9.2'*3'.

Brightness:Magnitude 10.

Brightness Profile:The central outskirts of this nebula grows brighter compared to the far outskirts of this nebula.

Challenge Rating:Extremely Difficult.

Description

-----------

The shape of this nebula looks like a duck together with its head and bill upon observing this both through my Ultra High Contrast Filter and my OIII Filter.By observing this nebula through my OIII filter the prominent N-S regions are visible whereby a 9th magnitude star is at its SE edge marks the duck's eye.To some observers this nebula's shape looks like a bubble.In this nebula there are plenty of areas of even and uneven brightness.

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