#1  
Old 14-02-2008, 10:50 AM
Rob_K
Registered User

Rob_K is offline
 
Join Date: Oct 2006
Location: Bright, Vic, Australia
Posts: 2,098
Observation Report 13/14 Feb 08

Beautiful night last night and I was determined to get at least one short session in before the waxing moon takes over the sky. Took the scope out in the backyard just before midnight and was greeted with dark skies, but just a touch of milkiness that would prohibit the hunt for very faint fuzzies. Still, I’d bet the average city dweller would kill for skies like that!

Centaurus & adjacent constellations were pretty well placed between two patches of tall trees, and seemed like as good a place as any to have a look.

Time: 11:45pm-12:30am, Wed 13-Thur 14 February 2008 (UT+11)
Location: My backyard, Bright, NE Vic
Telescope: Tasco 4.5” f8 reflector on Alt-Az mount
EP: 21mm Celestron X-Cel unless otherwise stated (x43)
Transparency: Reasonable (8/10), slight milkiness in atmosphere
Seeing: Poor – fair (3-4/10)

NGC5139, Omega Centaurus in Centaurus – Mag 3.7 and one of the most glorious sights in the night sky IMO! At low power it was beautiful – bright & crinkly! With 8mm X-Cel ep (x112), it gave surprisingly good views and resolution despite the conditions. However, higher powers do dim it off significantly in this scope.

NGC4945 in Centaurus – Mag 9.2 galaxy. A large, cigar-shaped dim haze, with no structure visible. Averted vision helped in seeing the extent of the galaxy. Quite impressive really, like a "poor man's" NGC253!

NGC5286 in Centaurus – Mag 7.3 globular cluster. A little gem this one, very small and quite bright, right next to ε Centauri, a bright, distinctly orange star. There’s a tiny PN somewhere close by, but didn’t have detailed charts and didn’t bother trying to tease it out.

NGC3918 in Centaurus – Mag 8.4 planetary nebula, the “Blue Planetary”. Easily spotted at low power as a tiny bright non-stellar object with a distinct pale bluish tinge. With 8mm X-Cel ep (x112), the disc was quite prominent, but the colour seen at low power disappeared and no detail was visible. Poor seeing meant the disc of the PN was oscillating somewhat too. First time I’ve seen this one!

NGC5128 in Centaurus – Mag 7.3 galaxy, “Centaurus A”. Quite bright, largish round patch, with the central dust lane easily visible in averted vision and in-and-out in direct vision.

NGC5102 in Centaurus – Mag 10.5 galaxy. This one is close to bright star Iota Centauri, and it helped (but wasn’t essential) to put the star just outside the FOV. Very tiny, elongated, with an almost stellar central brightening. Quite dim, and very difficult to make out any extension.

NGC5253 in Centaurus – Mag 11 galaxy. Not far from M83, this galaxy appeared tiny, dim and unremarkable. Very similar in my scope to NGC5102, above.

M83 in Hydra – Mag 7.91 galaxy, the “Southern Pinwheel Galaxy”. Always like this one – has a small, almost stellar core, and a largish, faint, roughly circular extension. Little detail visible, and I have had much better views of it in this scope.

M68 in Hydra – Mag 7.8 globular cluster. Larger than 5286 above, this gc is round, fairly bright, with increasing brightness towards centre. Not terribly remarkable, but all globulars are things of wonder!

M104 in Virgo – Mag 9 galaxy, the “Sombrero Galaxy”. This appeared as a small bright edge-on, with the dust lane visible particularly in averted vision. It is one of the few dim fuzzies that will sustain higher magnification in these small scopes. With the 8mm X-Cel ep (x112) the dust lane became clearer, and the structure of the galaxy more obvious.

NGC5068 in Virgo – Mag 10.5 galaxy. This one was quite easy to see as a larger, very dim amorphous haze, with no brighter core or any other structure visible. Definitely not one for higher powers in this scope!

Well, that was it, short & sweet – and with four objects (Blue Planetary + 5102, 5253, 5068) I’d never seen before, I’d call it successful too!

Cheers -
Reply With Quote
  #2  
Old 14-02-2008, 11:12 AM
erick's Avatar
erick (Eric)
Starcatcher

erick is offline
 
Join Date: Dec 2006
Location: Shoalhaven Heads
Posts: 8,469
Thanks Rob, that's added to my list of targets.

Not quite "kill", but sure am envious!

Great read! Clouds and some showers down south for us.
Reply With Quote
  #3  
Old 14-02-2008, 11:46 AM
ngcles's Avatar
ngcles
The Observologist

ngcles is offline
 
Join Date: Dec 2006
Location: Billimari, NSW Central West
Posts: 1,566
Hi Rob,

I continue to be very impressed by how far you are pushing your little Tasco. I tip's me lid to ya!

Just a couple of notes. The bright yellow/orange star next to the GC NGC 5286 is "M Centauri" (G8 III) and it is a condsiderable annoyance in observing the GC. Epsilon Centauri is quite nearby only 2.3 degrees southwest of the cluster and is a B1 III star with a B-V of -0.173 that should look cold white tending bluish but is not in the same field as the cluster.

The PNe you mention near NGC 5286 is NGC 5307 which I think will prove too much of a stretch for 10cm -- but have a go, you never know! It is 45 arc-mins in PA 77 (ie ENE of the globular). Mag 12.1 and 22" dia.

NGC 5102 probably holds the distinction of being the closest "lenticular" type (So) galaxy to the Milky Way -- though in some places it is classifiied as an Sa. It is a certain member of the nearby M83/Cen A* cluster of galaxies and as you note, Lambda Centauri is a real pain in observing (or imaging) it. I remember reading somewhere that it seems to be remarkably quiet in X-rays, strangely blue for its type, and has an unusually small number of G.Cs for a galaxy of its size/mass -- it is a small galaxy. From memory, in mass is in the same ball-park as the LMC, but only has 4 GCs (??) -- probably due to tidal stripping during close encounters with its really big neighbours.

Similarly, NGC 5068 is a possible member of the M83 group -- it has long been regarded as such because it has a very similar R/V, but it is a long, long way from the cluster's centre of mass and may instead be an isolated "field galaxy" that is not gravitationally bound to the cluster. Its overall structure is remarkably similar to the Milky Way (though a lot less massive). Look at an image of NGC 5068:

http://www.capella-observatory.com/I...es/NGC5068.htm

and then look at a diagram of the "barred" model of the Milky Way.

http://math.ucr.edu/home/baez/milky_way_bar.jpg

The bar and some spiral structure in NGC 5068 can be seen in 40cm. There is a faint but really lovely edge-on spiral close-by (50 arc-mins) to the south -- NGC 5084.

Enjoyed your report as ususal!

Best,

Les D
Reply With Quote
  #4  
Old 14-02-2008, 12:13 PM
§AB
Its only a column of dust

§AB is offline
 
Join Date: Aug 2007
Location: New Iceland
Posts: 761
thanks Rob for another quality report! Great to see you making the most out of the little 4.5 incher, as I former 4.5" user myself I can say that I did thorougly enjoy it.

Did you see the small elliptical galaxy NGC 4976, it's located only half a degree east of 4945?

Keep up the good work buddy
Reply With Quote
  #5  
Old 14-02-2008, 01:26 PM
Rob_K
Registered User

Rob_K is offline
 
Join Date: Oct 2006
Location: Bright, Vic, Australia
Posts: 2,098
Thanks all - observing was pretty rushed, but unfortunately that's my life just at the minute!

Les, thanks so much for the additional information, and the clarification with M Centauri. I can understand how the star might interfere with viewing this globular, but at the low powers I use I find it a strikingly beautiful 'conjunction'. No doubt if you were trying to resolve the cluster the story would be different! As far as tiny PNs go, I generally acknowledge that most are out of my reach, because even when they're 'bright' enough at low powers I can't push the magnification up to get any sense of their structure.

SAB, there are a few dim galaxies around NGC4945, including 4945A at a bit fainter than mag 13, and 4976 at about 11. I was aware of them from a photo I'd seen in the Hawaiian Astr Soc on-line deep sky atlas (a great source for visual observing, with photos, maps & descriptions on a constellation-by-constellation basis), but didn't see them last night - will have another look at this area on a better night.

http://www.hawastsoc.org/deepsky/ima...n/ngc4945s.jpg

The 3 brighter galaxies will fit easily in my FOV (the fourth shown is WAY out of my league, LOL!).

Here's a link to the constellations listings of the HAS:

http://www.hawastsoc.org/deepsky/constellations.html


Cheers -
Reply With Quote
  #6  
Old 14-02-2008, 03:18 PM
§AB
Its only a column of dust

§AB is offline
 
Join Date: Aug 2007
Location: New Iceland
Posts: 761
Thanks Rob, just found 4945A in the MSA tucked in close to a relatively bright star. 4945A might prove difficult in my 10", as it appears to have low surface brightness and very close proximity to the star. I will try this tonight. The 4th galaxy is ESO 219-7 and I have a gut feeling that it might actually be easier than 4945A. Looks like its clearing up with reasonable transparency so I'm going on an all night galaxy hunt in Centaurus and Hydra tonight
Reply With Quote
Reply

Bookmarks

Thread Tools
Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +10. The time is now 12:31 PM.

Powered by vBulletin Version 3.8.7 | Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
Advertisement
SkyWatcher Australia
Advertisement
NexDome Observatories
Advertisement
Bintel
Advertisement
Lunatico Astronomical
Advertisement
Meade Australia
Advertisement
Celestron Australia
Advertisement
OzScopes Authorised Dealer
Advertisement
Astronomy and Electronics Centre
Advertisement