#1  
Old 01-11-2010, 05:11 PM
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Lismore Bloke (Paul)
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Observations 30-10-2010

Hi everyone, I'm posting up the notes after last night's session. Very good it was too.
The Argo is definitely helping me to see deeper, as I can use averted vision to pick up faint objects that I would normally use direct vision for.

Cheers, Paul.




Dew was virtually nil, wind light. Seeing was about 6 out of 10, but a bit mushy over 200X. Transparency 7 out of 10. Telescope was 12” Dobsonian, eyepieces as below.
All observations were checked with this excellent site:
http://messier45.com/cgi-bin/dsdb/dsb.pl
Details of size, magnitude etc, were taken from here also.

NGC 1369 GX (ERIDANUS)
RA 03 36 45.22 DEC -36 15 28.2
SIZE 89”X67”
MAG 14.2j
CLASS SB(a)
EP 12mm Nagler (125x)
This tiny galaxy is classed as a S-shaped barred spiral member of the Fornax Cluster. This is an object that I would normally give myself little chance of picking up, if it were not for the Argo. It took me to the field without wasting time, and a scan around the FOV with my favourite galaxy EP, the 12mm, revealed its nature. It showed as a tiny oval shaped core, and some time scanning around suggested a fainter envelope, but I marked this envelope as “doubtful”, on the edge of reliable vision. I don’t trust my vision in such faint, extended things like outer envelopes around galaxies. Now that I’ve started to use the 12mm more, it is replacing the 17 as my favourite, it seems to have less “distortion” than the 17, excellent sharpness and about the right magnification to show galaxies in more detail without testing the conditions here too much.

NGC 1427A GX (ERIDANUS)
RA 03 40 10.47 DEC -35 37 38.4
SIZE 2.2’X1.5
MAG 13.4P
CLASS Im III
EP 12mm Nagler (125x)
This is another small galaxy that the Argo picked up. It shows as an oval shaped object with even illumination and no suggestion of any outer regions. I was doubtful that I had identified it correctly, so I drew a rough thumbnail in the notebook, showing the galaxy and the field stars. This was checked with the maps and photos in Deep Sky Browser (link above).

NGC 1532 GX (ERIDANUS)
RA 04 12 03.8 DEC -32 52 25
SIZE 5.6’x1.8’
MAG 11.32b
CLASS Sbc II-III
EP 12mm Nagler (125x)
I just love galaxies in pairs and groups and this wonderful example of a spiral and its small companion is hard to beat. The core was oval shaped and bright and the outer spiral arms clearly visible directly – no averted vision here.

NGC 1531 GX (ERIDANUS)
RA 04 11 59.1 DEC -32 51 05
SIZE 1.0’x0.8’
MAG 12.1
CLASS E6
EP 12mm Nagler (125x)
This little galaxy seems to be all core, not much of an envelope seen. The plane of this one is at about 90 degrees to NGC 1532. It makes for a very attractive combination. The high surface brightness of this elliptical makes it easy to see.

NGC 1068 GX (CETUS) (M77)
RA 02 42 40.83 DEC -00 00 48.4
SIZE 7.8’x6.7’
MAG 9.13V
CLASS Sb, Sy1h
EP 17mm Nagler (88x)
This is a nice galaxy to study, the centre showed as an oval shaped glow, with no core visible. Averted vision started to show the spiral arms sweeping around, but due to my difficulties in seeing form and detail in such things, I can only say that they were there. Darker skies may reveal more details that I can see from home, as there are knots of HII regions studded along the arms and it would be good to see them. It would be interesting to compare notes on this one from those in darker areas.

NGC 7163 GX (PISCIS AUSTRINUS)
RA 21 59 20.42 DEC -31 52 54.2
SIZE 1.8’x1.2
MAG 13.41b
CLASS Sb
EP 9mm Nagler (167x)
This galaxy was picked up after I did a fresh Argo align on a nearby object, just to make finding more accurate. I also did a thumbnail sketch of this field, as the magnitude should make it difficult. Again, this small galaxy showed up because of the tiny bright core that the 9mm revealed. There are outer regions visible on photos, but again, I’ve marked these down as doubtful.

NGC 7089 GC (AQUARIUS) (M2)
RA 21 59 33 29.3 DEC -00 49 23
SIZE 12.9’
MAG 6.52Vb
CLASS II
EP 17mm Nagler (88x) 9mm Nagler (167x)
Beautiful globular, perfectly symmetrical. The core was tightly packed with no resolution. The outer edges had quite a few stars resolved. When I switched to the 9mm it really came alive. Like other bright globulars (NGC 104 in particular) they appear 3 dimensional when you fill the field with them. The class (II) indicated the tight and dense concentration of this one.

NGC 6981 GC (AQUARIUS) (M72)
RA 20 53 27.9 DEC -12 32 13
SIZE 5.9’
MAG 9.3
CLASS IX
EP 12mm Nagler (125x)
This globular was rather dim and much less spectacular than M2. Rather ragged looking with some stars resolved at edges. The class of IX (out of XII – the loosest and I the tightest and most concentrated) indicated its appearance.

HICKSON 88 (Galaxy Cluster) (AQUARIUS)
Members: NGC 6975, 6976, 6977, 6978.
EP 17mm Nagler (88x)
I took advantage of the Argo’s tour mode to have a look at some of the galaxy groups listed in the Hickson Catalogue. Quite a few of these are tough objects for suburbia, but I was able to see two of this group of four with some certainty and another probable. The faintest one wasn’t seen. I didn’t sketch the field of these, tiredness was setting in, so no notes were taken. I will return to it before it sinks too low into the more light-polluted west. Quite pleased to have seen some of these objects. I had a look at Hickson 91’s position but could not record faithfully that I saw anything definite.
For those who have the dark skies to try these galaxy groups out, this site is useful:
http://www.raycash.us/deepsky/hickson.htm

The last object was the Saturn Nebula (NGC 7009). The extensions (ansae) were suspected, but perhaps more on one side. The 12mm gave the best view, the 7mm (214x) was too mushy. No O-III filter yet, that may make a difference.

Thanks for looking.

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Old 01-11-2010, 06:52 PM
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Paddy (Patrick)
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Lovely report Paul. 1532 + 1 are favourites of mine the small one diving into the heart of the larger. Great to hear that you're finding the Argo Navis so useful. I like your description of M2 also -e specially the 3-d sense.

When you talk about your favourite ep for galaxies, it reminds me of a post by Les Dalrymple in which he said that the optimum exit pupil for galaxes is 2. Your 12 mm would give 2.4 - abetter fit with this rule than your 17mm. Your 9 mm could be even better if this rule is all that applies.
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Old 01-11-2010, 06:54 PM
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Paddy (Patrick)
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Also, thanks for the link to the Hickson site - looks very interesting and useful.
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Old 01-11-2010, 07:49 PM
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Lismore Bloke (Paul)
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Thanks Patrick, is was an excellent night. I'm finding that the Argo is helping me to go deeper, and I'm not wasting time trying to find faint objects. The Argo means I am on the object and averted vision is allowing me to see fainter details, rather than using direct vision to try and find something manually - and not seeing it at all. Cheers, Paul.
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Old 03-11-2010, 08:14 PM
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Nice report there Paul! Here's a sweet galaxy pair I accidentally stumbled upon a fantastic pair: IC 5250A/B in Tucana. Try this one, it is an excellent pair, very compact pair, but both members bright with high surface brightness. Excellent in a 12" scope and superior to many better known NGC galaxies out there.

Another favourite of mine is Hickson 90 in Pisces Austrinus, this one's a ripper, 3 bright galaxies in an extremely compact group, all high surface brightness so makes for a pretty sight. A bright interacting pair (resolvable with 12") is complemented by a HSB elliptical 1' NW, and a 4th fainter member lies 6' N of the group.

Quote:
Lovely report Paul. 1532 + 1 are favourites of mine the small one diving into the heart of the larger. Great to hear that you're finding the Argo Navis so useful. I like your description of M2 also -e specially the 3-d sense.

When you talk about your favourite ep for galaxies, it reminds me of a post by Les Dalrymple in which he said that the optimum exit pupil for galaxes is 2. Your 12 mm would give 2.4 - abetter fit with this rule than your 17mm. Your 9 mm could be even better if this rule is all that applies.
I find high magnification superior to low ones when observing small faint galaxies. It really brings them out. In my scope the 8mm LVW gives about 2mm exit pupil @ 166x, but I find it of limited usefullness when observing small faint galaxies, I find myself reaching for the 5 and 3.5mm which give exit pupils of 1.1 and 0.8mm and much better contrast with tiny faint objects, to me atleast
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Old 03-11-2010, 09:13 PM
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Lismore Bloke (Paul)
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Thanks for the kind words Sab. Gee it's good to be at the eyepiece again after so much crap weather. Using the Argo is allowing me to use the shorter EP's, not having to go wide trying to find things. The seeing is the only thing limiting use of the 9 and 7. We're a bit closer to the tropics up here. I'll try for those target suggestions when I get the chance. Nice sketch of those GX's in Tucana. Cheers, Paul.
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