PDA

View Full Version here: : Thors Helmet - NGC2359


iceman
03-02-2006, 06:33 AM
Is anyone else smitten with this object like I am?

I saw this object for the first time at SPSP last year, and I guess I was spoiled by having my first view in Mike Kerr's 25" dob. It was an outstanding view, very photographic in its appearance with the shape of the "helmet" really standing out thanks to the aperture, and the dark skies. It was viewed without a filter.

After being gob-smacked by the view in the 25", I went back to looking at it through my 10" (still at SPSP), and while there was nowhere near the amount of detail it was still a very pleasing nebula to look at.

With Canis Major not in the sky for the last 6 months, I'd almost forgotten about this object, but over the last few observing sessions I've been taking the opportunity to reacquaint myself with this nebula.

My latest observations in my scope have compared the view with and without my DGM Optics NPB filter - this object definitely responds favourably to a narrowband filter, as it dims the surrounding starlight and enhances the contrast of the nebula. It can take some time at the eyepiece to really grasp the shape and structure of it, so don't give up after a 3-second view.

I was fortunate enough to view the nebula through Wazza's 18" truss dob at IISAC 2006 last weekend, using a OIII filter. Again a very pleasing view, and confirms again that aperture and a narrowband filter really make a difference on this one.

Anyone else have any thoughts on this beautiful object?

What prompted me to post was seeing a beautiful H-a image of the object on APOD today (http://antwrp.gsfc.nasa.gov/apod/ap060202.html).

Hitchhiker
03-02-2006, 07:57 AM
Had a look at this for the first time at Lostock through Andrew's 20". I was very impressed! I think Andrew used a UHC filter.

This is an object that I will have to hunt down in my SCT. I don't have any narrowband filters but it will be interesting to observe, nonetheless.

I remember Thor's Helmet being featured in A S & T a couple of months ago - it was mentioned that, in smaller scopes, it looks like a cartoon ducks head! I must admit this is what I first saw in Andrew's scope until I picked up the dimmer 'wing'. :lol:

davidpretorius
03-02-2006, 08:10 AM
thanks mike, i will have a look for this one!

ausastronomer
03-02-2006, 08:35 AM
Mike,

This is a nebula formed around a Wolf Rayet star HD56925 in Canis Major. Andrew Murrell wrote an excellent article on Wolf Rayet stars which starts on page 72 of the Nov/Dec 2004 edition of Sky and Space. The article contains a lot of information on Wolf Rayet stars and in particular "Thors Helmut" as well as a great pic of Thors Helmut. Definately worth reading if this target rows your boat.



Also just to clarrify something regarding your comment about the OIII filter. A UHC filter is a "Narrowband" filter, whereas an OIII filter is known as a "line filter" because it allows only a "single" emission line to pass. A H-Beta or "Horsehead" filter is also a line filter. A UHC or narrowband filter allows more than one emission line across a narrow band of the spectrum.

CS-John B

dhumpie
03-02-2006, 03:14 PM
Yup this is a nice one alright and it is easily visible with some detail in my C6 Celestron/Vixen as well with the UHC. We got very good views of it through Andrew's (astro_south) 12.5" Truss a while back.

Darren

astro_south
03-02-2006, 04:02 PM
Darren - you should have seen it out at Leyburn last weekend. Easily got both "horns" of the helmet extending out with the OIII filter in my 12.5". I won't mention what it looked like in the 30" apart from WOW :prey2: ;) (even though I was teattering on the top of the ladder)

It really is a great object and responds so well to filtering.

Astroman
03-02-2006, 05:03 PM
I saw this object for the first time through my 8", WOW looks good, wonder what its like through a 16" :)

mickoking
03-02-2006, 07:49 PM
It looked great thru my 120mm refractor with an OIII filter, as Bruce would say... Speeeecial :P