#1  
Old 26-09-2011, 09:08 PM
Paddy's Avatar
Paddy (Patrick)
Canis Minor

Paddy is offline
 
Join Date: Jun 2007
Location: Strangways, Vic
Posts: 2,208
Observations 24/9/11 in desperandum ad astra

A couple of "clear" nights recently. The first last Friday was more than a little trying due to seeing and transparency. Still, I did manage some obs. Here is the report of that adventure!

Observation notes 24/9/11

Telescope 400mm f4.9 tri-dob reflector
Eyepieces 28mm UWAN, 17,13,9 mm Naglers, Paracorr
Navigation: Night Sky Observer’s Guide (NSOG) and Uranometria

2230

Seeing extremely poor due to high winds – even low magnifications show stars as boiling blobs. Transparency abysmal due to smoke.

Who but a fool would observe galaxies under these circumstances?

Aquarius Dwarf Galaxy

175X Faint 5’x3’ haze elongated E-W with a line of 3 faint stars along the southern edge, one on the NW corner and one on the NE

NGC 7492 GC in Aquarius

175X Faint round 6’ haze with 3 faint stars just resolved (possibly foreground). Foreground stars also preceding and following the GC in an otherwise sparse star field. No core and poorly concentrated.

Neptune

135X Seeing very poor. A faint bluish disc.

NGC 7172/7173/7174/7176 GX in Pisces Austrinus

175X 7174 and 7176 at first appear as one 2’x1’ SW-NE ellipse, brighter at the NE end, but averted vision and patience reveal 2 galaxies, 7176 the brighter with stellar core and 7174 as a faint oval glow. 3’ to the west is the core of 7173 which looks about 1’ across and might be a elongated N-S. 7’ to the NW of 7173 is 7172 which is larger and fainter 2.5’x1.5’, a SW-NE oval with a nucleus just discernible in a faint halo

NGC 7201/7203/7204 GX in Pisces Austrinus

175X This is a nice SSE-NNW line of 3 galaxies of similar size and magnitude. 7201 is at the southern end and looks 1.5’x0.5’ E-W with a bright nucleus. 8’ to the north is 7203 which is a tad larger and rounder with a bright nucleus. A further 10’ to the north is 7204, a fainter 2’x1’ E-W oval with no nucleus.
Reply With Quote
  #2  
Old 26-09-2011, 09:31 PM
pgc hunter's Avatar
pgc hunter
Registered User

pgc hunter is offline
 
Join Date: Feb 2009
Location: Renmark, SA
Posts: 2,938
Made the best of a bad situation there, good work. Was considering going out last night but was a tad windy, and for some reason my gut was telling me bad seeing. Thanks for the confirmation!
Reply With Quote
  #3  
Old 26-09-2011, 09:36 PM
kustard's Avatar
kustard (Simon)
Great Sage == Heaven

kustard is offline
 
Join Date: Sep 2009
Location: Melbourne, Australia
Posts: 734
Good to see you out observing, really makes me feel I need to put the effort in and at least do something in my limited courtyard space.
Reply With Quote
  #4  
Old 27-09-2011, 08:48 PM
michaellxv's Avatar
michaellxv (Michael)
Registered User

michaellxv is offline
 
Join Date: Oct 2009
Location: Adelaide, Australia
Posts: 1,577
Nice work Paddy, sometimes you just have to get out there.
Reply With Quote
  #5  
Old 27-09-2011, 08:55 PM
Paddy's Avatar
Paddy (Patrick)
Canis Minor

Paddy is offline
 
Join Date: Jun 2007
Location: Strangways, Vic
Posts: 2,208
Quote:
Originally Posted by michaellxv View Post
...sometimes you just have to get out there.
Too true Michael. I find it very hard to stay inside on a clear moonless night however poor the conditions might be.
Reply With Quote
  #6  
Old 28-09-2011, 06:17 AM
orestis's Avatar
orestis
Registered User

orestis is offline
 
Join Date: Jun 2009
Location: southern highlands, Australia
Posts: 679
Nice observations in poor conditions,

The Ngc 7172/72/74/76 group is a nice little gathering of galaxies.

The other group you observed sounds interesting i'll give it a go next time i'm out.

Thanks for posting
regards Orestis
Reply With Quote
  #7  
Old 01-10-2011, 08:25 PM
Suzy's Avatar
Suzy
Searching for Travolta...

Suzy is offline
 
Join Date: Jan 2010
Location: Brisbane, Australia.
Posts: 3,672
Good on you Paddy!
And you still managed to bag some nice things despite the conditions.

See my little quote under my signature....
When you do that, then we'll start to worry
Reply With Quote
  #8  
Old 03-10-2011, 04:51 PM
Paddy's Avatar
Paddy (Patrick)
Canis Minor

Paddy is offline
 
Join Date: Jun 2007
Location: Strangways, Vic
Posts: 2,208
Quote:
Originally Posted by Suzy View Post
Good on you Paddy!
And you still managed to bag some nice things despite the conditions.

See my little quote under my signature....
When you do that, then we'll start to worry
I'll let you know when that starts happening. It is good to live on the dry side of the Great Divide
Reply With Quote
  #9  
Old 04-10-2011, 01:58 PM
madbadgalaxyman's Avatar
madbadgalaxyman (Robert)
Registered User

madbadgalaxyman is offline
 
Join Date: Mar 2011
Location: Brisbane
Posts: 913
Very Good observation, Paddy, to disentangle the NGC 7174 plus NGC 7176 pair.

N7174 is a highly distorted object of "disky" morphology, with plenty of disturbed-looking dust, and it forms an overlap pair with the elliptical galaxy NGC 7176.

It looks like NGC 7174 is somehow stretched out, rather than being just a normal undisturbed galaxy:

Click image for larger version

Name:	N7173(topR)__7174(botR)_7176(botL)_AtlasOfStrsInEarlyTypeGalaxies.gif
Views:	6
Size:	97.7 KB
ID:	101713

(The above image is from the Atlas of Structures in Early Type Galaxies.)

Of the four galaxies in this compact group of galaxies, which is known as Hickson Compact Group 90 (= HICK 90)(= HCG 90), it seems to me that NGC 7172 is the most likely to show some kind of internal structure in visual observations, as it has an "equatorial" dust lane which is quite broad and which is noticeably distorted and/or non-planar;

Click image for larger version

Name:	N7172_R + J __equals Red plus Blue____(AAO DSS2) + (SERC DSS1)_download from Aladin.jpg
Views:	8
Size:	134.8 KB
ID:	101714

The above image of NGC 7172 is a composite of two DSS images which I downloaded from the "Aladin previewer" (my favourite version of the Digitized Sky Survey).

I have in front of me a paper copy of Paul Hickson's "Atlas of Compact Groups of Galaxies", including images of all 100 compact groups; this Atlas is a nice tool for frontier-level visual observers, because the included images of the groups are not too detailed, so they do bear some relation to what can be seen visually.

cheers, Robert

P.S. NGC 7172 has a Seyfert nucleus, so you might be seeing some of the light from the Active Galactic Nucleus at the very centre of this galaxy..... but it is extremely hard to disentangle the contribution of the central active nucleus from that of the surrounding material (e.g. bulge light, central star formation, etc.)

Last edited by madbadgalaxyman; 04-10-2011 at 02:12 PM. Reason: more info
Reply With Quote
  #10  
Old 04-10-2011, 11:30 PM
madbadgalaxyman's Avatar
madbadgalaxyman (Robert)
Registered User

madbadgalaxyman is offline
 
Join Date: Mar 2011
Location: Brisbane
Posts: 913
Oh, and just one more thing....

"Just for fun and profit", here is a pair of images of NGC 7172 from a paper by S. Hameed and N. Devereux :

Click image for larger version

Name:	N7172.jpg
Views:	6
Size:	179.8 KB
ID:	101721

The Left panel is optical continuum light (red light), and the Right panel is H-alpha line only.
Reply With Quote
  #11  
Old 06-10-2011, 11:15 AM
Paddy's Avatar
Paddy (Patrick)
Canis Minor

Paddy is offline
 
Join Date: Jun 2007
Location: Strangways, Vic
Posts: 2,208
Thanks Robert,

I'll try a revisit of 7172 under better conditions and see what other structure is visible. Quite a list of observing challenges that I'm putting together from your posts!
Reply With Quote
  #12  
Old 07-10-2011, 12:30 PM
madbadgalaxyman's Avatar
madbadgalaxyman (Robert)
Registered User

madbadgalaxyman is offline
 
Join Date: Mar 2011
Location: Brisbane
Posts: 913
Paddy,
N7172 is going to be a tough nut to crack, but given the amount that you do see in other objects, I think that there is a good chance that you will crack it.

You live away from the major cities, I do believe.
This must be a great blessing for a visual observer.
I always had to drive three or four hours to my observing site, and then face the prospect of being clouded out. Perhaps my large amount of time-commitment relative to my very modest actual amount of useful observing time, was why I stopped doing regular visual observing and astrophotography.....the ever-increasing masses of unanalyzed imaging data on the internet make it much more efficient for me to spend my limited free time with other people's data. In any case, I am primarily interested in the morphologies and properties of galaxies, so I will use whatever data is best for this very specialized purpose.

Best regards, robert

The "warped and bent" and/or "thickened" and/or "non-planar" dust disk in NGC 7172 is something that I must pay more attention to. I have a large "Rogues Gallery" on disk drive...which is full of many weird and wonderful Spirals and S0 Galaxies that have a wide variety of strange non-planar features (bends, twists, thickenings, tilts, etc, instead of simply the canonical "planar galaxy" that we find in the old textbooks)

Last edited by madbadgalaxyman; 07-10-2011 at 12:37 PM. Reason: correction and more info
Reply With Quote
  #13  
Old 07-10-2011, 07:23 PM
Paddy's Avatar
Paddy (Patrick)
Canis Minor

Paddy is offline
 
Join Date: Jun 2007
Location: Strangways, Vic
Posts: 2,208
I do live under lovely dark skies. I have great respect for the commitment of those who pursue observing and live in cities!
Reply With Quote
  #14  
Old 08-10-2011, 09:31 PM
madbadgalaxyman's Avatar
madbadgalaxyman (Robert)
Registered User

madbadgalaxyman is offline
 
Join Date: Mar 2011
Location: Brisbane
Posts: 913
Paddy,
Currently, I probably manage about five or six visual observing sessions per year with a 12 inch Newt./Dobsonian. The interest is probably not there to pursue it very regularly, as I did for 26-27 years.
I am fortunate enough, about one month from every two, to be able to spend 5 hours every day thinking about nothing else apart from galaxies , and this has to be my focus.
The other month out of the two, I am usually studying "dirt"(invertebrates in the soil) or practicing my other scientific hobbies..... such as looking for the earliest fossil evidence of multicellular life.
Reply With Quote
  #15  
Old 11-10-2011, 05:42 AM
SteveG (Steve)
Registered User

SteveG is offline
 
Join Date: Jan 2010
Location: Berkeley, CA, USA
Posts: 39
I'm very impressed you were able to pick up the Aquarius Dwarf in poor conditions! LEDA lists a pretty daunting surface brightness of only 16.56(B) mag per square arcmin.

I wonder if others have seen this local group dwarf and under what conditions?

Steve
Reply With Quote
  #16  
Old 11-10-2011, 09:27 PM
Paddy's Avatar
Paddy (Patrick)
Canis Minor

Paddy is offline
 
Join Date: Jun 2007
Location: Strangways, Vic
Posts: 2,208
Thanks Steve. I was a bit surprised myself, but for once I was sure it wasn't imagination. When I cross checked with a DSS image, it all checked out. I was quite chuffed!
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 07:13 AM.

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