Object of the Week Apr 22, 2012 - NGC 4361

[Dragan]

Planetary Nebula in Corvus


Magnitude: 10.3
Central Star Mag: 13.2

RA 12 24 30.76
DEC -18 47 05.4
(J2000.0)

AKA:

ESO 573-PN 019
P-K 294+43 01

154

At nearly 2 minutes across, NGC 4361 is a moderately bright PN in Corvus that often goes unnoticed. The PN has been observed in scopes as small as 4.25” so it’s a good target for anyone. If you’re able to observe 4361 in a larger scope, you may start to pick up a hint of symmetry that can resemble the arms of a spiral galaxy. Being that it’s so close to Virgo, it isn’t unheard of this PN being mistaken for a galaxy.

As a side, Megastar reveals quite a few MAC galaxies in the vicinity of 4361, including MAC 1224-1841, a nice faint edge on that’s listed as 16th magnitude. Unless you’re observing with large glass under really dark and transparent skies, I’ll save the MACs for this weeks bonus point objects!

So next time you’re out and checking out M104 or other Virgo fuzzies, be sure to swing a little further south to Corvus. If you’ve never seen NGC 4361, you may just be in for a little surprise.

And remember,

GIVE IT A GO AND LET US KNOW!

GOOD LUCK AND GREAT VIEWING!

[Clear Skies]

Here's a screenshot from my observing guide.

155

[Jimi Lowrey]

Last Friday night of TSP I had Scott of Tele-Vue,Howie Glatter and Marc Emde from Germany over at my observatory to view with me on the 48". We were trying out the new 8MM Delos eyepiece (and I must say it is a excellent eyepiece with super contrast and unbelievable light transmission) We were in Corvus looking at some galaxies and I went to the PN NGC 4361for a change of objects. The planetary was showing lots of detail and something caught my eye up close to the edge of the field of the 8MM Delos at 610X. I centered the faint small nebulas patch and could hold it with direct vision. Scott was next up the ladder and after he settled in at the eyepiece I told him were to look in the eyepiece for the faint nebula and he picked it up very easily, Howie and Marc also could see it quite easily.

The next day I looked up on line and could not find a image that showed this halo. so I am sure that we are the first to see this outer halo on NGC 4362 visually.

I am not sure if this halo is know or not I have contacted some professional astronomers and they will get back to me with what they find out it might be a new discovery! I will post what I find out.

This is a image that I enhanced with DS9 to show the nebula.
157

[Clear Skies]

Hi Jimi,

The faint patches are definitely "something", not an image artefact. They show up, albeit very faintly, on the more recent (than POSS2 DSS) SuperCOSMOS Blue image: http://www-wfau.roe.ac.uk/sss/tmp/pixel/tempfiles/14117.gif
Could be part of a faint outer shell of NGC4361, could be extremely faint galaxies, could be ... ? BTW, NED doesn't name anything that should be visible at the given positions: http://ned.ipac.caltech.edu/cgi-bin/nph-objsearch?search_type=Near+Name+Search&objname=ngc4361&radius=10&hconst=73&omegam=0.27&omegav=0.73&corr_z=1&z_constraint=Unconstrained&z_value1=&z_value2=&z_unit=z&ot_include=ANY&nmp_op=ANY&out_csys=Equatorial&out_equinox=J2000.0&obj_sort=Distance+to+search+center&of=pre_text&zv_breaker=30000.0&list_limit=5&img_stamp=YES (within 10' of the PN).


Victor

[Steve Gottlieb]

I know most of this detail is visible in much smaller scopes, but here's the view from 48" a couple of months ago --

(48", 20 Feb 2012): the unusual structure in this planetary shocked me at 488x as previous views in my 17.5" and 18" had only showed a hint of detail. Two components on the planetary are large bulbous lobes or wings with an irregular surface brightness, that jut out of the central region in a WNW and ESE direction with the WNW lobe slightly brighter. More surprising were two arms and loops, similar to spiral arms in a galaxy, that extend out to the NE and SW and curve clockwise. The arm to the southwest is very thin where it emerges from the central portion, so it appeared partially detached. The arm on the NE side clearly bends south but is not as sharply defined. Between the lobes (WNW and ESE) and arms (SW and NE) are darker gaps or regions creating a unique, basically symmetric shape that is elongated SW-NE (arms are longer), ~1.8'x1.4'. At the center is a very bright mag 13 central star. A fainter, more roundish halo envelops the brighter components.

[Uwe Glahn]

I remember that the "arm structure" was not an easy target with the 16". With 24" under Namibian skies it was much more easy and could be detect with the first look through the eyepiece.

Jimi, the outer structure is very interesting. Hard to say if it is an halo fragment or some background galaxies. The nearly opponent positions, the similar distances (5,1'S, 6,6' NE) and the (similar) brightness on the blue plates let it looks like two halo knots.

191

[FaithJ]

A bit late to the party here but anyway...

I observed NGC 4361 during our local star party at the end of March this year. It's fairly low for us up here at 50°N and I was having to bend down to look through my 18" scope!


At 90x 4361 is bright, round and 'fluffy' looking with the central star easily visible. At 247x, the outer edges look fluffy. There is some darkening in the centre and the PN stands out well with the OIII filter. 18" f/4.3 dob

[Sue French]

Very late to the party, but what the heck. I've observed NGC 4361 several times with various instruments. Here's the latest:

4 May 2008, 10:40pm EDT
368/2207mm Newtonian
Seeing and Transparency fair to poor.
35mm Panoptic: Fairly large planetary, easily visible, brighter center. Central star visible.
13mm Nagler: Nebula is roundish with a brighter center around the central star that's elongated approximately east-west, and what look for all the world like two brighter spiral arms - one emanating from the SE side of the elongated bright area and then curving west, and an opposing arm emanating NW and curving east. OIII filter: East-west center stands out better. UHC filter enhances east-west center and base of spiral arms.
9mm Nagler: The brighter center is actually cocked WxN - ExS, and it isn't as as bright south of the central star.